JP2019091792A - Nonaqueous lithium-type power storage element - Google Patents

Abstract

To provide a nonaqueous lithium-type power storage element, capable of achieving both high input/output characteristics in a wide temperature range and excellent high temperature durability, and also capable of holding characteristics for a long period of time even in a high voltage region.SOLUTION: A nonaqueous lithium-type power storage element includes a negative electrode, a positive electrode and a nonaqueous electrolyte. The negative electrode includes a negative electrode collector and a negative electrode active material layer containing a negative electrode active material. A ratio S/Fbetween an element concentration Sof S and an element concentration Fof F which are obtained by XPS on a surface of the negative electrode active material layer is 0.025-0.5. The positive electrode includes a positive electrode collector and a positive electrode active material layer containing a positive electrode active material. When A(m/cm) represents a BET specific surface area per unit area of the positive electrode active material layer, 0.2≤A≤10 is satisfied. The ratio S/C between an element concentration Sof S and an element concentration C which are obtained by XPS on a surface of the positive electrode active material layer is 0.001-0.05.SELECTED DRAWING: None

Description

  The present invention relates to a non-aqueous lithium type storage element.

In recent years, from the viewpoint of effective use of energy aiming at preservation of the global environment and resource saving, a power smoothing system or a late-night power storage system for wind power generation, a distributed power storage system for home based on photovoltaic technology, storage for electric vehicles Systems have attracted attention.
The first requirement of the batteries used in these storage systems is the high energy density. Lithium ion batteries have been vigorously developed as potential candidates for high energy density batteries capable of meeting such requirements.
The second requirement is high output characteristics. For example, in a combination of a high efficiency engine and a storage system (for example, a hybrid electric vehicle) or a combination of a fuel cell and a storage system (for example, a fuel cell electric vehicle) There is.
At present, electric double layer capacitors, nickel hydrogen batteries and the like are being developed as high power storage devices.

  Among the electric double layer capacitors, one using activated carbon for the electrode has an output characteristic of about 0.5 to 1 kW / L. This electric double layer capacitor has high durability (cycle characteristics and high temperature storage characteristics), and has been considered as an optimum device in the field where the high output is required. However, its energy density is only about 1 to 5 Wh / L. Therefore, the electric double layer capacitor needs further improvement of the energy density.

  On the other hand, the nickel hydrogen battery currently adopted in the hybrid electric vehicle has the same high output as the electric double layer capacitor and has an energy density of about 160 Wh / L. However, researches are being vigorously carried out to further enhance the energy density and the output as well as the durability (in particular, the stability at high temperatures).

  In addition, also in lithium ion batteries, researches for increasing the output are being advanced. For example, lithium ion batteries have been developed which can provide a high output exceeding 3 kW / L at 50% of the discharge depth (the ratio (%) of the discharge amount to the discharge capacity of the storage element). However, its energy density is 100 Wh / L or less, and it is designed to intentionally suppress the high energy density, which is the most characteristic feature of a lithium ion battery. In addition, its durability (cycle characteristics and high-temperature storage characteristics) is inferior to that of the electric double layer capacitor. Therefore, the lithium ion battery is used in a range in which the depth of discharge is narrower than the range of 0 to 100% in order to give practical durability. Since the capacity of the lithium ion battery that can actually be used is further reduced, researches are being actively conducted to further improve the durability.

  As described above, there is a strong demand for practical use of a storage element having high energy density, high output characteristics, and durability. However, the existing storage elements described above have advantages and disadvantages. Therefore, new storage elements that satisfy these technical requirements are required. As a promising candidate, a storage element called a lithium ion capacitor is attracting attention and is actively developed.

A lithium ion capacitor is a type of storage element (non-aqueous lithium type storage element) using a non-aqueous electrolytic solution containing a lithium salt, and adsorbs the same anion as the electric double layer capacitor at about 3 V or more at the positive electrode A storage element that performs charge and discharge by non-Faraday reaction by desorption, and Faraday reaction by insertion and extraction of lithium ions similar to lithium ion batteries in the negative electrode.
The electrode materials generally used for the above-mentioned storage element and the characteristics thereof are summarized as follows: when using materials such as activated carbon for the electrodes and performing charge and discharge by adsorption / desorption (non-Faraday reaction) of ions on the activated carbon surface, High output and high durability can be realized, but the energy density is low (in this case, the energy density is a reference (for example, 1 times the relative value)). On the other hand, when using an oxide or carbon material for the electrode and performing charge and discharge by the Faraday reaction, the energy density becomes high (The energy density in this case is a relative value of non-Faraday reaction reference using activated carbon, for example, 10). However, there are problems with durability and output characteristics.
As a combination of these electrode materials, the electric double layer capacitor is characterized by using activated carbon (1 × energy density) for the positive electrode and the negative electrode, and performing charge and discharge by non-Faraday reaction for both positive and negative electrodes, high output and high durability It has the feature that the energy density is low (positive 1 ×× negative 1 = 1).

  Lithium ion secondary batteries are characterized by using lithium transition metal oxide (energy density 10 times) for the positive electrode and carbon material (energy density 10 times) for the negative electrode, and charging and discharging both by positive and negative electrodes by Faraday reaction. Although it is energy density (10 times of positive electrode × 10 times negative electrode = 100), there are problems in output characteristics and durability. Furthermore, the depth of discharge must be limited in order to satisfy the high durability required for hybrid electric vehicles and the like, and in lithium ion secondary batteries, only 10 to 50% of the energy can be used.

  Lithium ion capacitors are characterized by using activated carbon (energy density 1 time) for the positive electrode, carbon material (energy density 10 times) for the negative electrode, non-faradaic reaction at the positive electrode, and Faraday reaction at the negative electrode. It is an asymmetric capacitor combining the features of the multilayer capacitor and the lithium ion secondary battery. And, while having high output and high durability, the lithium ion capacitor has high energy density (positive 1 ×× negative 10 × = 10), and it is necessary to limit the depth of discharge like a lithium ion secondary battery. It is a feature that there is not.

Examples of applications of lithium ion capacitors include storage applications in railways, construction machines, automobiles and the like. In these applications, because of the harsh operating environment, the capacitors used need to have excellent properties in a wide temperature range from high temperatures above 40 ° C. to low temperatures below 0 ° C. In a high temperature environment of 40 ° C. or higher, performance degradation caused by gas generation due to decomposition of the electrolyte has become a problem.
As a countermeasure against such problems, additives are added to the non-aqueous electrolyte solution, and a film made of the decomposition product is formed on the surfaces of the negative electrode active material and the positive electrode active material. There is a technology for suppressing the decomposition of the non-aqueous electrolyte and improving the durability of the battery.
As technologies related to this, Patent Documents 1 and 2 propose a storage element in which two types of additives having different structures are contained in an electrolytic solution. Further, in Patent Document 3, an electric storage element in which a certain amount of film is formed on the surface of the negative electrode active material by adding an additive to the non-aqueous electrolyte solution is disclosed in PTL 4 as an additive to the non-aqueous electrolyte solution. An electric storage element is proposed in which a film is formed on the surface of the positive electrode active material by adding.

In addition, in a low temperature environment of 0 ° C. or lower, there is a problem that the internal resistance of the storage element becomes large and a rapid output drop is caused.
As means for solving such problems, Patent Documents 5 and 6 propose lithium ion capacitors in which the low temperature characteristics are improved by containing a specific solvent in the electrolytic solution. In Patent Document 6, by optimizing the ratio of the mixed solvent in the electrolytic solution and enhancing the compatibility with a specific negative electrode active material, it is possible to improve low temperature characteristics and suppress gas generation at the time of high temperature test. Lithium ion capacitors have been proposed. Further, in Patent Document 7, by containing a specific amount of a specific alkali metal compound in the positive electrode active material layer, high input / output characteristics over a wide temperature range and gas generation and characteristic deterioration due to decomposition of the electrolyte under high temperature environment Lithium ion capacitors have been proposed that can achieve both the suppression of

  In recent years, there has been a demand for higher energy density in non-aqueous lithium-type storage elements, and in order to achieve the high energy density, higher voltage is being studied. However, when the non-aqueous lithium-type storage element is operated at a high voltage, specifically, at a high potential of 4.1 V or more, the electrolytic decomposition of the electrolyte solvent at the positive electrode significantly occurs and a large amount of gas is generated. Since generation occurs and the characteristic deterioration of the storage element accompanying it, a problem arises in durability. As a means to solve such a problem, in Patent Document 8, a lithium ion is used to form a film on the positive electrode by containing a phosphorus-containing additive in the electrolytic solution, and to suppress the decrease in cycle characteristics and the gas generated during the cycle. Electrolyte solutions for secondary batteries have been proposed.

  In the present specification, the amount of mesopores is calculated by the BJH method, and the amount of micropores is calculated by the MP method. The BJH method is proposed in Non-Patent Document 1. The MP method means a method of determining micropore volume, micropore area, and micropore distribution using “t-plot method” (Non-patent document 2), and is shown in Non-patent document 3 .

JP, 2014-27196, A Unexamined-Japanese-Patent No. 2013-206791 Unexamined-Japanese-Patent No. 2014-137861 JP, 2015-191806, A JP, 2015-70032, A JP, 2011-258915, A International Publication No. 2017/126691 JP, 2017-69146, A

E. P. Barrett, L .; G. Joyner and P.J. Halenda, J.J. Am. Chem. Soc. , 73, 373 (1951) B. C. Lippens, J.J. H. de Boer, J.J. Catalysis, 4319 (1965) R. S. Mikhail, S .; Brunauer, E. et al. E. Bodor, J. et al. Colloid Interface Sci. , 26, 45 (1968)

The techniques described in Patent Documents 1, 2 and 4 suppress gas generation and electrode deterioration during high temperature storage, but the low temperature characteristics are not sufficient. Patent Document 3 provides a capacitor having excellent cycle characteristics at high temperatures, but it can not be said that the characteristics change after the high temperature storage test is not sufficient.
The lithium ion capacitors described in Patent Documents 4 and 5 can improve the characteristics of the storage element at low temperatures, but can not be said to be sufficient for improvement of the durability at high temperatures. Patent Document 5 provides a lithium ion capacitor in which gas generation at the time of a high temperature test is suppressed in addition to the improvement of the low temperature characteristics, but the suppression of the characteristic change after the high temperature test is not sufficient.
Patent Document 7 proposes a storage element which is improved in low-temperature characteristics and excellent in characteristics at the time of high-temperature test, but it can not be said that high-voltage durability of 4.1 V or more is sufficient. Moreover, although the electrolyte solution excellent in the cycle characteristic in a high voltage area | region is proposed by patent document 8, it can not be said about high temperature storage durability and a low temperature characteristic that it is enough.

  As described above, in the conventional lithium ion capacitor, improvements are made focusing on one of the low temperature characteristics and the high temperature durability, but it is possible to simultaneously satisfy the low temperature characteristics and the high temperature durability. Not in. That is, the input / output characteristics and durability of the storage element in a wide temperature range from high temperature to low temperature, which is important for practical use, are insufficient. In addition, the resistance to high voltages, specifically to high voltages of 4.1 V or more, is not considered.

  Therefore, the problem to be solved by the present invention is to be able to achieve both high input / output characteristics in a wide temperature range and excellent high temperature durability, and further to provide the characteristics even in the high voltage region of 4.1 V or more. An object of the present invention is to provide a non-aqueous lithium storage element which can be held for a long time.

  The present inventors use activated carbon as a positive electrode active material in a non-aqueous lithium storage element, form a specific film on the positive electrode active material layer and the negative electrode active material layer, and control the specific surface area of the positive electrode active material layer. Therefore, it is necessary to simultaneously achieve high input / output characteristics in a wide temperature range and gas generation due to decomposition of the electrolyte under high voltage and high temperature environment of 4.1 V or higher and suppression of characteristic deterioration of the storage element associated therewith. It has been found that it is possible to complete the present invention. That is, the present invention is as follows.

{式（１）中、Ｒ^１〜Ｒ^４はそれぞれ独立に、水素原子、ハロゲン原子、ホルミル基、炭素数２〜７のアシル基、ニトリル基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜７のアルキルカルボニルオキシ基、又は炭素数２〜７のアルキルオキシカルボニル基を表す。}

{式（２−１）〜（２−５）中のＲ^５〜Ｒ^２８は、それぞれ独立に、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は炭素数１〜１２のハロゲン化アルキル基を表し；そして、
式（２−１）〜（２−３）及び（２−５）中のｎは、それぞれ独立に、０〜３の整数である。}
［３］ 前記化学式（１）で表される化合物が、チオフェン、２−メチルチオフェン、３−メチルチオフェン、２−シアノチオフェン、３−シアノチオフェン、２，５−ジメチルチオフェン、２−メトキシチオフェン、３−メトキシチオフェン、２−クロロチオフェン、３−クロロチオフェン、２−アセチルチオフェン、及び３−アセチルチオフェンから成る群から選択される１種以上であり、
前記化学式（２−１）で表される化合物が、エチレンスルファート及び１，３−プロピレンスルファートから成る群から選択される１種以上であり、
前記化学式（２−２）で表される化合物が、１，３−プロパンスルトン、２，４−ブタンスルトン、１，４−ブタンスルトン、１，３−ブタンスルトン、及び２，４−ペンタンスルトンから成る群から選択される１種以上であり、
前記化学式（２−３）で表される化合物が、１，３−プロペンスルトン及び１，４−ブテンスルトンから成る群から選択される１種以上であり、
前記化学式（２−４）で表される化合物が、３−スルフォレンであり、そして、
前記化学式（２−５）で表される化合物が、亜硫酸エチレン、１，２−亜硫酸プロピレン、及び１，３−亜硫酸プロピレンから成る群から選択される１種以上である、［２］に記載の非水系リチウム型蓄電素子。
［４］ 前記非水系電解液が、ジメチルカーボネート、エチルメチルカーボネート、ジエチルカーボネート、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート、及びフルオロエチレンカーボネートから成る群から選択される少なくとも１種の非水溶媒を含有する、［１］〜［３］のいずれか一項に記載の非水系リチウム型蓄電素子。
［５］ 前記非水系電解液が、ＬｉＰＦ_６及びＬｉＢＦ_４から成る群から選択される１種以上を含有する、［１］〜［４］のいずれか一項に記載の非水系リチウム型蓄電素子。
［６］ 前記非水系電解液が、ＬｉＮ（ＳＯ_２Ｆ）_２を含有する、［１］〜［５］のいずれか一項に記載の非水系リチウム型蓄電素子。
［７］ 前記正極集電体及び前記負極集電体が、それぞれ、無孔の金属箔である、［１］〜［６］のいずれか一項に記載の非水系リチウム型蓄電素子。
［８］ 前記正極活物質に含まれる活性炭が、ＢＪＨ法により算出した直径２０Å以上５００Å以下の細孔に由来するメソ孔量をＶ１（ｃｃ／ｇ）、ＭＰ法により算出した直径２０Å未満の細孔に由来するマイクロ孔量をＶ２（ｃｃ／ｇ）とするとき、０．３＜Ｖ１≦０．８、及び０．５≦Ｖ２≦１．０を満たし、かつ、ＢＥＴ法により測定される比表面積が１，５００ｍ^２／ｇ以上３，０００ｍ^２／ｇ以下を示す活性炭を含む、［１］〜［７］のいずれか一項に記載の非水系リチウム型蓄電素子。
［９］ 前記正極活物質に含まれる活性炭が、ＢＪＨ法により算出した直径２０Å以上５００Å以下の細孔に由来するメソ孔量Ｖ１（ｃｃ／ｇ）が０．８＜Ｖ１≦２．５を満たし、ＭＰ法により算出した直径２０Å未満の細孔に由来するマイクロ孔量Ｖ２（ｃｃ／ｇ）が０．８＜Ｖ２≦３．０を満たし、かつ、ＢＥＴ法により測定される比表面積が２，３００ｍ^２／ｇ以上４，０００ｍ^２／ｇ以下を示す活性炭を含む、［１］〜［８］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１０］ 前記正極活物質が、リチウムイオンを吸蔵及び放出可能な遷移金属酸化物を更に含む、［１］〜［９］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１１］ 前記遷移金属酸化物が、層状構造、スピネル構造、及びオリビン構造から選ばれる構造を有する遷移金属酸化物である、［１０］に記載の非水系リチウム型蓄電素子。
［１２］ 前記遷移金属酸化物が、Ｌｉ_ｘＮｉ_ａＣｏ_ｂＡｌ_{（１−ａ−ｂ）}Ｏ_２｛ａ及びｂは、それぞれ、０．２＜ａ＜０．９７、０．２＜ｂ＜０．９７を満たす。｝、Ｌｉ_ｘＮｉ_ｃＣｏ_ｄＭｎ_{（１−ｃ−ｄ）}Ｏ_２｛ｃ及びｄは、それぞれ、０．２＜ｃ＜０．９７、０．２＜ｄ＜０．９７を満たす。｝、Ｌｉ_ｘＣｏＯ_２、Ｌｉ_ｘＭｎ_２Ｏ_４、Ｌｉ_ｘＦｅＰＯ_４、Ｌｉ_ｘＭｎＰＯ_４｛ｘは０≦ｘ≦１を満たす。｝、及びＬｉ_ｚＶ_２（ＰＯ_４）_３｛ｚは０≦ｚ≦３を満たす。｝から成る群から選択される１種以上である、［１０］又は［１１］に記載の非水系リチウム型蓄電素子。
［１３］ 前記負極活物質がリチウムイオンでドープされており、そのドープ量が、前記負極活物質の単位質量当たり５３０ｍＡｈ／ｇ以上２，５００ｍＡｈ／ｇ以下である、［１］〜［１２］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１４］ 前記負極活物質のＢＥＴ比表面積が１ｍ^２／ｇ以上１，５００ｍ^２／ｇ以下である、［１］〜［１３］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１５］ 前記負極活物質が粒子状であり、その平均粒子径が、１μｍ以上１０μｍ以下である、［１３］又は［１４］に記載の非水系リチウム型蓄電素子。
［１６］ セル電圧４．２Ｖでの初期の内部抵抗をＲａ（Ω）、静電容量をＦ（Ｆ）、電力量をＥ（Ｗｈ）、電極体を収納している外装体の体積をＶ（Ｌ）、及び環境温度−１０℃における内部抵抗をＲｂとした時、以下の（ａ）、（ｂ）、及び（ｃ）の要件：
（ａ）ＲａとＦの積Ｒａ・Ｆが０．３以上３．０以下である、
（ｂ）Ｅ／Ｖが１５以上５０以下である、及び
（ｃ）Ｒｂ／Ｒａが１０以下である
を同時に満たす、［１］〜［１５］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１７］ セル電圧４．２Ｖでの初期の内部抵抗をＲａ（Ω）、セル電圧４．２Ｖ及び環境温度６０℃において２か月間保存した後の２５℃における内部抵抗をＲｃ（Ω）とした時、以下の（ｄ）及び（ｅ）の要件：
（ｄ）Ｒｃ／Ｒａが０．３以上３．０以下である、並びに
（ｅ）セル電圧４．２Ｖ及び環境温度６０℃において２か月間保存した時に発生するガス量が、２５℃において３０×１０^−３ｃｃ／Ｆ以下である、
を同時に満たす、［１］〜［１６］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１８］ 前記負極、前記正極、前記セパレータ、及び前記非水系電解液が、外層体に収納されており、
前記外装体が、金属缶又はラミネート包材である、［１］〜［１７］のいずれか一項に記載の非水系リチウム型蓄電素子。
［１９］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子を含む、蓄電モジュール。
［２０］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、電力回生システム。
［２１］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、電力負荷平準化システム。
［２２］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、無停電電源システム。
［２３］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、非接触給電システム。
［２２］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、エナジーハーベストシステム。
［２３］ ［１］〜［１８］のいずれか一項に記載の非水系リチウム型蓄電素子、又は［１９］に記載の蓄電モジュールを含む、蓄電システム。 [1] A non-aqueous lithium-type storage element including a non-aqueous electrolyte containing a negative electrode, a positive electrode, a separator, and a lithium salt,
The negative electrode has a negative electrode current collector, and a negative electrode active material layer containing a negative electrode active material provided on one side or both sides of the negative electrode current collector, and the negative electrode active material contains lithium ions. Containing carbon material that can be occluded and released,
The elemental concentration of S determined based on the peak area of 168 eV in the S2p spectrum obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the negative electrode active material layer is S _{168 eV} (atomic%), peak area of 685 eV in the F1s spectrum The element concentration ratio S _{168 eV} / F _{685 eV} is 0.025 or more and 0.5 or less, where the element concentration of F determined on the basis of F is _{685 eV} (atomic%),
The positive electrode includes a positive electrode current collector and a positive electrode active material layer including a positive electrode active material provided on one side or both sides of the positive electrode current collector, and the positive electrode active material includes activated carbon. ,
Assuming that the specific surface area per unit area of the positive electrode active material layer measured by the BET method is A (m ² / cm ² ), 0.2 ≦ A ≦ 10, and
The elemental concentration of S determined based on the peak area of 164 eV in the S2p spectrum obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the positive electrode active material layer is S _{164 eV} (atomic%) and the peak area of C in the C1s spectrum The nonaqueous lithium-type electrical storage element _whose elemental concentration ratio S _164eV / C is 0.001 or more and 0.05 or less, where C (atomic%) is the elemental concentration of C determined on the basis of.
[2] At least one selected from the compound X represented by the following chemical formula (1) and the compounds represented by the following chemical formulas (2-1) to (2-5): The non-aqueous lithium type electrical storage element as described in [1] which contains the compound Y of and.

{In the formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a formyl group, an acyl group having 2 to 7 carbon atoms, a nitrile group, an alkyl group having 1 to 6 carbon atoms, 1 carbon atom It represents an alkoxy group of -6, an alkylcarbonyloxy group having 2 to 7 carbon atoms, or an alkyloxycarbonyl group having 2 to 7 carbon atoms. }

{Formula ^{(2-1) ~ (2-5) R} 5 ~R 28 in each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated having 1 to 12 carbon atoms Represents an alkyl group; and
N in formulas (2-1) to (2-3) and (2-5) is each independently an integer of 0 to 3. }
[3] The compound represented by the chemical formula (1) is thiophene, 2-methylthiophene, 3-methylthiophene, 2-cyanothiophene, 3-cyanothiophene, 2,5-dimethylthiophene, 2-methoxythiophene, 3 One or more selected from the group consisting of methoxythiophene, 2-chlorothiophene, 3-chlorothiophene, 2-acetylthiophene, and 3-acetylthiophene,
The compound represented by the chemical formula (2-1) is one or more selected from the group consisting of ethylene sulfate and 1,3-propylene sulfate.
The compound represented by the chemical formula (2-2) is selected from the group consisting of 1,3-propane sultone, 2,4-butane sultone, 1,4-butane sultone, 1,3-butane sultone, and 2,4-pentane sultone One or more selected
The compound represented by the chemical formula (2-3) is one or more selected from the group consisting of 1,3-propene sultone and 1,4-butene sultone,
The compound represented by the above chemical formula (2-4) is 3-sulfurene, and
The compound according to [2], wherein the compound represented by the chemical formula (2-5) is one or more selected from the group consisting of ethylene sulfite, propylene 1,2-sulfite, and propylene propylene 1,3-sulfite Non-aqueous lithium type storage element.
[4] The non-aqueous electrolyte contains at least one non-aqueous solvent selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and fluoroethylene carbonate. The non-aqueous lithium type electrical storage element as described in any one of [1]-[3].
[5] The non-aqueous lithium-type storage element according to any one of [1] to [4], wherein the non-aqueous electrolytic solution contains one or more selected from the group consisting of LiPF ₆ and LiBF ₄ .
[6] The non-aqueous lithium-type storage element according to any one of [1] to [5], wherein the non-aqueous electrolyte contains LiN (SO ₂ F) ₂ .
[7] The non-aqueous lithium-type storage element according to any one of [1] to [6], wherein the positive electrode current collector and the negative electrode current collector are respectively non-porous metal foils.
[8] The activated carbon contained in the positive electrode active material is V1 (cc / g), which is a fine pore having a diameter of 20 Å or more and 500 Å or less, which is calculated by the BJH method. Assuming that the amount of micropores derived from pores is V2 (cc / g), the ratio satisfies 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0, and the ratio measured by the BET method surface area comprises activated carbon having the following 1,500 m ² / g or more ^{3,000m 2 / g, [1]} ~ nonaqueous lithium-type storage element according to any one of [7].
[9] The amount of mesopores V1 (cc / g) derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by BJH satisfies 0.8 <V1 ≦ 2.5 for activated carbon contained in the positive electrode active material The micropore amount V2 (cc / g) derived from pores having a diameter of less than 20 Å calculated by the MP method satisfies 0.8 <V2 ≦ 3.0, and the specific surface area measured by the BET method is 2, 300 meters ² / g or more 4,000m comprises activated carbon showing a ² / g or less, [1] a non-aqueous lithium-type storage element according to any one of to [8].
[10] The non-aqueous lithium-type storage element according to any one of [1] to [9], wherein the positive electrode active material further contains a transition metal oxide capable of inserting and extracting lithium ions.
[11] The nonaqueous lithium-type storage element according to [10], wherein the transition metal oxide is a transition metal oxide having a structure selected from a layered structure, a spinel structure, and an olivine structure.
[12] The transition metal oxide is Li _x Ni _a Co _b Al _(1-a-b) O ₂ {a and b are respectively 0.2 <a <0.97, 0.2 <b < Meet 0.97. _{}, Li x Ni c Co d} Mn (1-c-d) O 2 {c and d, respectively, satisfy 0.2 <c <0.97,0.2 <d < 0.97. }, Li _x CoO ₂ , Li _x Mn ₂ O ₄ , Li _x FePO ₄ , Li _x MnPO ₄ {x satisfies 0 ≦ x ≦ 1. }, And Li _z V ₂ (PO ₄ ) ₃ {z satisfies 0 ≦ z ≦ 3. The non-aqueous lithium-type storage element according to [10] or [11], which is at least one selected from the group consisting of
[13] [1]-[12], wherein the negative electrode active material is doped with lithium ions, and the doping amount is 530 mAh / g to 2,500 mAh / g per unit mass of the negative electrode active material The non-aqueous lithium type electrical storage element as described in any one.
[14] The non-aqueous lithium-type storage element according to any one of [1] to [13], wherein a BET specific surface area of the negative electrode active material is 1 m ² / g to 1,500 m ² / g.
[15] The non-aqueous lithium-type storage element according to [13] or [14], wherein the negative electrode active material is in the form of particles, and the average particle diameter thereof is 1 μm to 10 μm.
[16] The initial internal resistance at cell voltage 4.2 V is Ra (Ω), electrostatic capacity is F (F), electric energy is E (Wh), and the volume of the package containing the electrode assembly is V (L) and the internal resistance at an ambient temperature of −10 ° C. is Rb, the following requirements (a), (b) and (c):
(A) The product Ra · F of Ra and F is 0.3 or more and 3.0 or less,
(B) E / V is 15 or more and 50 or less, (c) Rb / Ra is 10 or less simultaneously, Non-aqueous lithium type electricity storage according to any one of [1] to [15] element.
[17] The initial internal resistance at cell voltage 4.2 V is Ra (Ω), internal resistance at 25 ° C. after storage for two months at cell voltage 4.2 V and environmental temperature 60 ° C. is Rc (Ω) The following requirements (d) and (e):
(D) Rc / Ra is 0.3 or more and 3.0 or less, and (e) the amount of gas generated when stored for 2 months at a cell voltage of 4.2 V and an environmental temperature of 60 ° C. is 30 × at 25 ° C. Less than 10 ^-3 cc / F,
The non-aqueous lithium type electrical storage element as described in any one of [1]-[16] which satisfy | fills simultaneously.
[18] The negative electrode, the positive electrode, the separator, and the non-aqueous electrolyte solution are contained in an outer layer body,
The non-aqueous lithium type electrical storage element as described in any one of [1]-[17] whose said exterior body is a metal can or laminate packaging material.
[19] A storage module comprising the non-aqueous lithium storage element according to any one of [1] to [18].
[20] A power regeneration system including the non-aqueous lithium-type storage element according to any one of [1] to [18], or the storage module according to [19].
[21] A power load leveling system including the non-aqueous lithium-type storage element according to any one of [1] to [18] or the storage module according to [19].
[22] An uninterruptible power supply system including the non-aqueous lithium-type storage element according to any one of [1] to [18] or the storage module according to [19].
[23] A noncontact power feeding system including the non-aqueous lithium-type storage element according to any one of [1] to [18] or the storage module according to [19].
[22] An energy harvesting system comprising the non-aqueous lithium-type storage element according to any one of [1] to [18] or the storage module according to [19].
[23] A storage system comprising the non-aqueous lithium-type storage element according to any one of [1] to [18], or the storage module according to [19].

According to the present invention, a non-aqueous lithium-type storage element is compatible with high input / output characteristics in a wide temperature range and generation of gas due to decomposition of the electrolyte at high voltage and high temperature and suppression of characteristic deterioration of the storage element thereby. Can be provided.
The non-aqueous lithium-type storage element of the present invention is particularly preferable when applied as a lithium ion capacitor because the above-mentioned features can be exhibited to the maximum.

Hereinafter, embodiments of the present invention (hereinafter, referred to as “the embodiments”) will be described in detail, but the present invention is not limited to the embodiments. The upper limit value and the lower limit value in each numerical value range of the present embodiment can be arbitrarily combined to constitute an arbitrary numerical value range.
First, the meanings of terms used in the present specification will be described below.

[Non-porous current collector]
In the specification of the present application, the “non-porous current collector” refers to the degree to which lithium ions pass through the current collector at least in the region where the active material layer is provided, and the lithium ion concentration becomes uniform on the front and back of the electrode. Means a current collector having no holes. Therefore, within the scope of the effects of the present invention, a current collector having extremely small diameter or a very small amount of holes, and a current collector having holes in the region where the active material layer is not provided are not excluded. In the current collector, a region where the active material layer is not provided may have or may not have a hole.

[BET specific surface area, average pore size, amount of mesopores, and amount of micropores]
The BET specific surface area, the average pore size, the amount of mesopores, and the amount of micropores in the present specification are values determined by the following methods.
The sample is vacuum dried overnight at 200 ° C., and adsorption and desorption isotherms are measured using nitrogen as an adsorbate. Using the adsorption side isotherm obtained here, the BET specific surface area is the mesopores by dividing the total pore volume per mass by the BET specific surface area by the BET multipoint method or the BET one point method. The amount is calculated by the BJH method, and the micropore amount is calculated by the MP method.
The BJH method is a calculation method generally used for the analysis of mesopores and proposed by Barrett, Joyner, Halenda et al. (Non-Patent Document 1).
In addition, the MP method means a method of obtaining the micropore volume, the micropore area, and the micropore distribution by using the “t-plot method” (Non-patent document 2), which is described in R. S. It is a method devised by Mikhail, Brunauer, Bodor (non-patent document 3).

[Average particle size]
The average particle diameter in the present specification is the particle diameter at the point where the cumulative curve becomes 50% when the cumulative curve is determined with the total volume being 100% when the particle size distribution is measured using a particle size distribution measuring device (ie , 50% diameter (Median diameter)). This average particle size can be measured using a commercially available laser diffraction type particle size distribution measuring apparatus.

[Primary particle size]
As the primary particle diameter in the present specification, the powder is photographed for several fields of view with an electron microscope, and the particle diameter of about 2,000 to 3,000 particles in those fields of view is used with a fully automatic image processing device etc. It can be obtained by a method in which the primary particle diameter is obtained by measuring and arithmetically averaging these values.

Degree of dispersion
The degree of dispersion in the present specification is a value determined by a degree of dispersion evaluation test using a particle gauge specified in JIS K5600. That is, for a particle gauge having a groove of a desired depth depending on the particle size, a sufficient amount of sample is poured into the deep end of the groove and slightly overflows the groove. The long side of the scraper is parallel to the width direction of the gauge, and the cutting edge is placed in contact with the deep tip of the groove of the grain gauge. Then, while holding the scraper perpendicular to the surface of the gauge, the surface of the gauge is pulled at a uniform speed over a period of 1 to 2 seconds in the long side direction of the groove to a groove depth of 0. Then, within 3 seconds after pulling, light is observed by irradiating light at an angle of 20 ° to 30 ° with respect to the surface of the gauge, and a depth of a point where remarkable spots of the grain appear in the groove of the grain gauge. Read

[Viscosity (ηb) and TI value]
The viscosity (η b) and the TI value in the present specification are values determined by the following methods, respectively.
First, the stable viscosity ((eta) a) after measuring for 2 minutes or more on the conditions of temperature 25 degreeC and the shear rate 2 s- ¹ using an E-type viscosity meter is acquired. Next, the viscosity (ηb) measured under the same conditions as described above except that the shear rate is changed to 20 s ⁻¹ is obtained. The TI value is calculated by the formula of TI value = に よ り a / ηb, using the viscosity value obtained above. When the shear rate is increased from 2s ^-1 to 20s ^-1 , it may be increased in one step, or may be increased in multiple steps within the above range, and optionally while increasing the viscosity at the shear rate. Good.

[XPS]
By analyzing the electronic state of the element using XPS, the bonding state of the compound can be determined.
As an example of the measurement conditions of XPS, the following conditions can be mentioned, for example.
X-ray source: monochromized AlKα
X-ray beam diameter: 100 μmφ (25 W, 15 kV)
Pass energy (narrow scan): 58.70 eV
Charge neutralization: Yes Sweep number (narrow scan): 10 times (carbon, oxygen), 20 times (fluorine), 30 times (phosphorus), 40 times (elemental lithium), or 50 times (silicon)
Energy step (narrow scan): 0.25 eV
It is preferable to clean the surface of the sample by sputtering before the measurement of XPS. As conditions for sputtering, the following conditions can be mentioned, for example.
Acceleration voltage: 1.0kV
Sputtering range: 2 mm × 2 mm
Sputtering time: 1 minute (1. 25 nm / min in terms of SiO ₂ )

The assignments for the obtained XPS spectra can be as follows.
(Li1s)
Binding energy peak of 50 to 54 eV: LiO ₂ or Li—C bond peak of 55 to 60 eV: LiF, Li ₂ CO ₃ , or Li _x PO _y F _z (wherein, x, y, and z each represent 1 to 4) Is an integer of 6)
(C1s)
Binding energy: peak at 285 eV: C—C bond peak at 286 eV: C—O bond peak at 288 eV: COO
Peak at 290 to 292 eV: CO ₃ ^2- or C-F bond (O1s)
Peak of binding energy 527 to 530 eV: O ^2- (Li ₂ O)
The peaks of 531 to 532 eV are represented by CO, CO ₃ , OH, PO _x (in the formula, x is an integer of 1 to 4), SiO _x (in the formula, x is an integer of 1 to 4), a peak of 533 eV C—O, SiO _x (wherein, x is an integer of 1 to 4)
(F1s)
Peak of binding energy 685 eV: LiF
687 eV peak: C—F bond Li _x PO _y F _z (wherein, x, y and z each represent an integer of 1 to 6), or PF ₆ ⁻
(P2p)
Peak of binding energy 133 eV: PO _x (wherein, x is an integer of 1 to 4)
134 to 136 eV peak: PF _x (wherein, x is an integer of 1 to 6)
(Si2p)
Peak of binding energy 99 eV: peak of Si or silicide 101 to 107 eV: Si _x O _y (wherein, x and y are each arbitrary integers)
(S2p)
Peak of binding energy 162 eV to 167 eV: C-S-C bond Peak of 168 eV to 173 eV: SO _x (wherein x is an integer of 2 to 4)

  With respect to the obtained spectrum, in the case where the peaks overlap, it is preferable to assign the spectrum after performing peak separation assuming a Gaussian function or Lorentz function.

<< non-aqueous lithium type storage element >>
In general, a non-aqueous lithium-type storage element includes, as main components, a negative electrode, a positive electrode, a separator, and an electrolytic solution, which are accommodated in an outer package. As the electrolytic solution, an organic solvent in which a lithium salt is dissolved (hereinafter, referred to as "non-aqueous electrolytic solution") is used.
The non-aqueous lithium-type storage element of the present invention also includes a negative electrode, a positive electrode, a separator, and a non-aqueous electrolytic solution containing a lithium salt. In the non-aqueous lithium-type storage element of the present invention, preferably, an electrode body (electrode stack or electrode-wound body) in which a positive electrode and a negative electrode are stacked or wound with a separator interposed is in an outer package together with a non-aqueous electrolytic solution. It is stored and configured.

<Negative electrode>
The negative electrode has a negative electrode current collector and a negative electrode active material layer provided on one side or both sides of the negative electrode current collector.

[Anode current collector]
The material constituting the negative electrode current collector in the present embodiment is preferably a metal foil which has high electron conductivity and does not cause deterioration due to elution to a non-aqueous electrolytic solution and reaction with an electrolyte or ion. There is no restriction | limiting in particular as such metal foil, For example, aluminum foil, copper foil, nickel foil, stainless steel foil etc. are mentioned. A copper foil is preferable as the negative electrode current collector in the non-aqueous lithium-type storage element according to the present embodiment.
The metal foil used as the negative electrode current collector may be a normal smooth surface metal foil having no unevenness or through holes, or a metal having unevenness subjected to embossing, chemical etching, electrolytic deposition, blasting, etc. It may be a foil, or a metal foil having through holes such as an expanded metal, a punching metal, and an etching foil.
It is preferable that the negative electrode current collector in the present embodiment is non-porous from the viewpoints of easiness of preparation of the negative electrode, high electron conductivity, and the like.
The thickness of the negative electrode current collector is not particularly limited as long as the shape and strength of the negative electrode can be sufficiently maintained, but for example, 1 to 100 μm is preferable. When the negative electrode current collector has holes or irregularities, the thickness of the negative electrode current collector is determined based on the thickness of the region where no holes or irregularities are present.

[Anode active material layer]
The negative electrode active material layer contains a negative electrode active material.
The negative electrode active material layer may further contain optional components such as a conductive filler, a binder, and a dispersion stabilizer, as necessary.

(Anode active material)
As the negative electrode active material, a material capable of inserting and extracting lithium ions is used.
The negative electrode active material in the present embodiment is characterized by including a carbon material capable of inserting and extracting lithium ions.
The negative electrode active material may contain a negative electrode active material other than such a carbon material.

The negative electrode active material is preferably in the form of particles.
The average particle diameter of the particulate negative electrode active material is preferably 1 μm or more and 10 μm or less. The average particle size of the particulate negative electrode active material is preferably 2 μm or more or 2.5 μm or more, and 6 μm or less or 4 μm or less.

The BET specific surface area of the negative electrode active material is preferably 1 m ² / g or more and 1,500 m ² / g or less. A more preferable BET specific surface area of the negative electrode active material will be described later for each type of negative electrode active material.

The negative electrode active material is preferably doped with lithium ions.
In the present specification, the lithium ion doped into the negative electrode active material mainly includes three forms.
A first mode is lithium ions to be stored in advance as a design value in a negative electrode active material before manufacturing a non-aqueous lithium-type storage element.
A second embodiment is lithium ions stored in a negative electrode active material at the time of manufacturing and shipping a non-aqueous lithium type storage element.
A third embodiment is lithium ions stored in a negative electrode active material after using a non-aqueous lithium-type storage element as a device.
By doping the negative electrode active material with lithium ions, it is possible to control well the capacity and operating voltage of the obtained non-aqueous lithium type storage element.

The doping amount of lithium ion per unit mass of the negative electrode active material is preferably 530 mAh / g or more and 2,500 mAh / g or less. A more preferable doping amount will be described later for each material of the negative electrode active material.
Doping the lithium ion lowers the negative electrode potential. Therefore, when the negative electrode including the negative electrode active material doped with lithium ions is combined with the positive electrode, the voltage of the non-aqueous lithium-type storage element becomes high and the use capacity of the positive electrode becomes large. Therefore, the capacity and energy density of the obtained non-aqueous lithium type storage element become high.
When the doping amount is 530 mAh / g or more, lithium ions in the negative electrode active material are also favorably doped to irreversible sites which can not be detached once lithium ions are inserted, and further the negative electrode active material with respect to a desired lithium amount Can be reduced. Therefore, the thickness of the negative electrode active material layer can be reduced, and high energy density can be obtained. As the doping amount increases, the negative electrode potential decreases, and input / output characteristics, energy density, and durability improve.
On the other hand, when the doping amount is 2,500 mAh / g or less, there is no possibility that a side effect such as precipitation of lithium metal occurs.

In the present specification, the doping amount of lithium ions of the negative electrode active material in the non-aqueous lithium-type storage element at the time of shipping and after use can be known, for example, as follows.
First, the negative electrode active material layer is washed with ethyl methyl carbonate or dimethyl carbonate and air-dried, and then an extract solution extracted with a mixed solvent of methanol and isopropanol and a negative electrode active material layer after extraction are obtained. This extraction is typically performed in an Ar box at an ambient temperature of 23 ° C.
The amount of lithium contained in the extract solution obtained as described above and the negative electrode active material layer after extraction is respectively quantified using, for example, ICP-MS (inductively coupled plasma mass spectrometer) or the like. By determining the sum, the doping amount of lithium ions in the negative electrode active material can be known. Then, the value of the unit may be calculated by assigning the obtained value to the mass of the negative electrode active material subjected to extraction.

  Examples of carbon materials capable of absorbing and releasing lithium ions contained in the negative electrode active material layer in the present embodiment include non-graphitizable carbon materials; graphitizable carbon materials; carbon black; carbon nanoparticles; activated carbon; Graphite: Natural graphite; Graphitized mesophase carbon small spheres; Graphite whiskers; Amorphous carbonaceous materials such as polyacene materials; petroleum pitch, coal pitch, mesocarbon microbeads, coke, synthetic resin (such as phenol resin etc.) And carbonaceous materials obtained by heat-treating carbonaceous material precursors such as: pyrolyzate of furfuryl alcohol resin or novolac resin; fullerene; carbon nanofone; etc., and composite carbon materials of these, and the like.

  Preferred examples of the composite carbon material in the present embodiment are the following composite carbon materials 1 and 2. Either of these may be selected and used, or both of them may be used in combination.

-Composite carbon material 1-
The composite carbon material 1 is a composite carbon material in which a carbonaceous material is adhered to the base material using one or more kinds of carbon materials having a BET specific surface area of 100 m ² / g or more and 3,000 m ² / g or less as a base material. is there.

The substrate is not particularly limited, but activated carbon, carbon black, porous carbon template, high specific surface area graphite, carbon nanoparticles and the like can be suitably used.
BET specific surface area of the substrate in the composite carbon material 1 is preferably 100 m ² / g or more 1,500 m ² / g or less, more preferably 150 meters ² / g or more 1,100m ² / g or less, more preferably 180 m ² / g or more and 550 m ² / g or less. When the BET specific surface area is 100 m ² / g or more, the pores can be appropriately held, and the diffusion of lithium ions is improved, so that high input / output characteristics can be exhibited. On the other hand, when the BET specific surface area is 1,500 m ² / g or less, the charge / discharge efficiency of lithium ions is improved, and therefore the cycle durability is not impaired.

  It is preferable that the average particle diameter of the base material in the composite carbon material 1 is 0.5 μm or more and 20 μm or less. The lower limit is more preferably 1 μm or more, and still more preferably 2 μm or more. The upper limit is more preferably 10 μm or less, and still more preferably 8 μm or less. If the average particle size is 1 μm or more and 20 μm or less, good durability can be maintained.

  The mass ratio of the carbonaceous material to the base material in the composite carbon material 1 is preferably 10% by mass or more and 200% by mass or less. The mass ratio is more preferably 12% by mass to 180% by mass, still more preferably 15% by mass to 160% by mass, and particularly preferably 18% by mass to 150% by mass. If the mass ratio of the carbonaceous material is 10% by mass or more, the micropores possessed by the base material can be appropriately filled with the carbonaceous material, and the charge and discharge efficiency of lithium ions is improved, so that a good cycle can be achieved. It can show durability. In addition, when the mass ratio of the carbonaceous material is 200% by mass or less, the pores possessed by the base material can be appropriately held, and the diffusion of lithium ions becomes good, so that high input / output characteristics can be obtained. Can be shown.

  The doping amount of lithium ion per unit mass of the composite carbon material 1 is preferably 530 mAh / g or more and 2,500 mAh / g or less. The doping amount is more preferably 620 mAh / g or more and 2,100 mAh / g or less, still more preferably 760 mAh / g or more and 1,700 mAh / g or less, and particularly preferably 840 mAh / g or more and 1,500 mAh / g or less.

  Hereinafter, as a preferable example of the composite carbon material 1, a composite carbon material 1a in the case where an activated carbon is used as a base material and a carbonaceous material is adhered to the base material will be described.

In the composite carbon material 1a, the amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by BJH method is Vm1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 Å calculated by MP method It is preferable that 0.010 ≦ Vm1 ≦ 0.300 and 0.001 ≦ Vm2 ≦ 0.650, where Vm2 (cc / g).
The mesopore amount Vm1 is more preferably 0.010 ≦ Vm1 ≦ 0.225, and still more preferably 0.010 ≦ Vm1 ≦ 0.200. The micropore amount Vm2 is more preferably 0.001 ≦ Vm2 ≦ 0.200, still more preferably 0.001 ≦ Vm2 ≦ 0.150, and particularly preferably 0.001 ≦ Vm2 ≦ 0.100.

  If the mesopore amount Vm1 is 0.300 cc / g or less, the BET specific surface area can be increased, and in addition to the ability to increase the lithium ion doping amount, the bulk density of the negative electrode can be increased. As a result, the negative electrode can be thinned. In addition, when the micropore amount Vm2 is 0.650 cc / g or less, high charge and discharge efficiency with respect to lithium ions can be maintained. On the other hand, if the amount of mesopores Vm1 and the amount of micropores Vm2 are at least the lower limit (0.010 ≦ Vm1, 0.001 ≦ Vm2), high input / output characteristics can be obtained.

The BET specific surface area of the composite carbon material 1a is preferably 100 m ² / g or more and 1,500 m ² / g or less. More preferably, it is 150 m ² / g or more and 1,100 m ² / g or less, and further preferably 180 m ² / g or more and 550 m ² / g or less. When the BET specific surface area is 100 m ² / g or more, the pores can be appropriately held, and the diffusion of lithium ions is improved, so that high input / output characteristics can be exhibited. In addition, since the doping amount of lithium ions can be increased, the negative electrode can be thinned. On the other hand, when it is 1,500 m ² / g or less, the charge and discharge efficiency of lithium ions is improved, and therefore the cycle durability is not impaired.

  The average pore diameter of the composite carbon material 1a is preferably 20 Å or more, more preferably 25 Å or more, and still more preferably 30 Å or more, in order to obtain high input / output characteristics. On the other hand, in terms of achieving high energy density, the average pore size is preferably 65 Å or less, and more preferably 60 Å or less.

  The average particle diameter of the composite carbon material 1a is preferably 1 μm to 10 μm. The lower limit is more preferably 2 μm or more, and still more preferably 2.5 μm or more. The upper limit is more preferably 6 μm or less, and still more preferably 4 μm or less. When the average particle size is 1 μm to 10 μm, good durability can be maintained.

  The hydrogen atom / carbon atom atomic ratio (H / C) of the composite carbon material 1 a is preferably 0.05 or more and 0.35 or less, and more preferably 0.05 or more and 0.15 or less. When H / C is 0.35 or less, the structure (typically, a polycyclic aromatic conjugated structure) of the carbonaceous material deposited on the activated carbon surface is well developed and the capacity (energy) Density) and charge and discharge efficiency. On the other hand, when H / C is 0.05 or more, good energy density can be obtained because carbonization does not proceed excessively. H / C is measured by an elemental analyzer.

  The composite carbon material 1a has an amorphous structure derived from activated carbon of the base material, and at the same time, has a crystal structure derived mainly from the deposited carbonaceous material. According to the X-ray wide-angle diffraction method, in the composite carbon material 1a, the crystallite size in the c-axis direction obtained from the half-value width of this peak has an interplanar spacing d002 of (002) plane of 3.60 Å to 4.00 Å. Lc is preferably 8.0 Å or more and 20.0 Å or less, d002 is 3.60 Å or more and 3.75 Å or less, and the crystallite size Lc in the c-axis direction obtained from the half width of this peak is 11.0 Å It is more preferable that the thickness is 16.0 Å or less.

  As activated carbon used as a base material of said composite carbon material 1a, as long as the composite carbon material 1a obtained exhibits a desired characteristic, there is no restriction | limiting in particular. For example, commercial products obtained from various raw materials such as petroleum, coal, plants and polymers can be used. In particular, it is preferable to use activated carbon powder having an average particle diameter of 1 μm to 15 μm. The average particle diameter of the activated carbon used as the substrate is more preferably 2 μm or more and 10 μm or less.

In order to obtain the composite carbon material 1a having the pore distribution range defined in the present embodiment, the pore distribution of the activated carbon used for the substrate is important.
In the activated carbon, the amount of mesopores derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores having a diameter of less than 20 Å calculated by the MP method When V2 (cc / g) is satisfied, it is preferable that 0.050 ≦ V1 ≦ 0.500, 0.005 ≦ V2 ≦ 1.000, and 0.2 ≦ V1 / V2 ≦ 20.0.

  The mesopore amount V1 is more preferably 0.050 ≦ V1 ≦ 0.350, and still more preferably 0.100 ≦ V1 ≦ 0.300. The micropore amount V2 is more preferably 0.005 ≦ V2 ≦ 0.850, and still more preferably 0.100 ≦ V2 ≦ 0.800. The ratio of the amount of mesopores / the amount of micropores is more preferably 0.22 ≦ V1 / V2 ≦ 15.0, and still more preferably 0.25 ≦ V1 / V2 ≦ 10.0. When the amount of mesopores V1 of activated carbon is 0.500 or less and when the amount of micropores V2 is 1.000 or less, an appropriate amount of carbonaceous matter can be obtained to obtain the pore structure of the composite carbon material 1a in the present embodiment. Since it is sufficient to apply the material, the pore structure can be easily controlled. On the other hand, when the amount of mesopores V1 of activated carbon is 0.050 or more and when the amount of micropores V2 is 0.005 or more, when V1 / V2 is 0.2 or more, and V1 / V2 is 20.0 The structure is easily obtained also in the following cases.

  In the composite carbon material 1a, a carbonaceous material precursor is used as a carbon source of the carbonaceous material to be deposited on the substrate. The carbonaceous material precursor is an organic material that can be dissolved in a solid, a liquid, or a solvent, by which the activated carbon as a base material can be deposited by heat treatment. Examples of the carbonaceous material precursor include pitch, mesocarbon microbeads, coke, synthetic resin (for example, phenol resin etc.) and the like. Among these carbonaceous material precursors, it is preferable from the viewpoint of production cost to use an inexpensive pitch. Pitches are roughly classified into petroleum pitches and coal pitches. The petroleum pitch includes, for example, distillation residue of crude oil, fluid catalytic cracking residue (decant oil etc.), bottom oil derived from thermal cracker, ethylene tar obtained in naphtha cracking and the like.

  When the above pitch is used, the pitch is heat-treated in coexistence with activated carbon, and the volatile component or the thermal decomposition component of the pitch is thermally reacted on the surface of the activated carbon to deposit the carbonaceous material on the activated carbon. Material 1a is obtained. In this case, at a temperature of about 200 to 500 ° C., deposition of the volatilizable component or thermal decomposition component of the pitch into the activated carbon pore proceeds, and the reaction of the deposited component becoming a carbonaceous material proceeds at 400 ° C. or higher Do. The peak temperature (maximum reached temperature) at the time of heat treatment is appropriately determined depending on the characteristics of the composite carbon material 1 a to be obtained, the heat reaction pattern, the heat reaction atmosphere, etc., but is preferably 400 ° C. or more, more preferably Is from 450 ° C. to 1,000 ° C., and more preferably from about 500 to 800 ° C. The time for maintaining the peak temperature at the time of heat treatment is preferably 30 minutes to 10 hours, more preferably 1 hour to 7 hours, and still more preferably 2 hours to 5 hours. For example, when heat treatment is performed for 2 hours to 5 hours at a peak temperature of about 500 to 800 ° C., it is considered that the carbonaceous material deposited on the activated carbon surface is a polycyclic aromatic hydrocarbon. .

30 degreeC or more and 250 degrees C or less are preferable, and, as for the softening point of the pitch used as a carbonaceous material precursor, 60 degrees C or more and 130 degrees C or less are still more preferable. A pitch having a softening point of 30 ° C. or more has no problem in handling and can be precisely prepared. The pitch having a softening point of 250 ° C. or less contains a large number of relatively low molecular weight compounds. Therefore, the use of the pitch makes it possible to deposit even fine pores in activated carbon.
As a specific method for producing the above-mentioned composite carbon material 1a, for example, the activated carbon is heat-treated in an inert atmosphere containing hydrocarbon gas volatilized from the carbonaceous material precursor, and the carbonaceous material is covered in the gas phase. There is a method of putting on clothes. Alternatively, the activated carbon and the carbonaceous material precursor may be mixed in advance and subjected to heat treatment, or the carbonaceous material precursor dissolved in a solvent may be applied to activated carbon and dried, followed by heat treatment.

  It is preferable that the mass ratio of the carbonaceous material to the activated carbon in the composite carbon material 1a is 10% by mass or more and 100% by mass or less. This mass ratio is preferably 15% by mass to 80% by mass. When the mass ratio of the carbonaceous material is 10% by mass or more, the micropores possessed by the activated carbon can be appropriately filled with the carbonaceous material, and the charge and discharge efficiency of lithium ions is improved, so that the cycle durability is improved. There is no loss. In addition, when the mass ratio of the carbonaceous material is 100% by mass or less, the pores of the composite carbon material 1a are appropriately retained, and the specific surface area is maintained large. Therefore, as a result of being able to increase the doping amount of lithium ions, high output density and high durability can be maintained even if the negative electrode is thinned.

-Composite carbon material 2-
The composite carbon material 2 is a composite carbon material in which a carbonaceous material is adhered to the base material using one or more kinds of carbon materials having a BET specific surface area of 0.5 m ² / g or more and 80 m ² / g or less. is there. Although the base material in this case is not particularly limited, for example, natural graphite, artificial graphite, low crystal graphite, hard carbon, soft carbon, carbon black and the like can be suitably used.

BET specific surface area of the substrate in the composite carbon material 2 is preferably ^{1 m} 2 / g or more ^{50 m} 2 / g or less, more preferably 1.5 m ² / g or more ^{40 m} 2 / g or less, more preferably ^2m 2 / g or more 25 m ² / g or less. If this BET specific surface area is 1 m ² / g or more, a reaction site with lithium ions can be sufficiently secured, and high input / output characteristics can be exhibited. On the other hand, if the BET specific surface area is 50 m ² / g or less, the charge / discharge efficiency of lithium ions is improved, and the decomposition reaction of the non-aqueous electrolyte solution during charge / discharge is suppressed, thereby exhibiting high cycle durability. Can.

  The average particle size of the composite carbon material 2 is preferably 1 μm or more and 10 μm or less. The average particle size is more preferably 2 μm to 8 μm, and still more preferably 3 μm to 6 μm. When the average particle size is 1 μm or more, the charge and discharge efficiency of lithium ions can be improved, and high cycle durability can be exhibited. On the other hand, if the average particle diameter is 10 μm or less, the reaction area between the composite carbon material 2 and the non-aqueous electrolyte solution increases, so high input / output characteristics can be exhibited.

  The mass ratio of the carbonaceous material to the base material in the composite carbon material 2 is preferably 1% by mass or more and 30% by mass or less. The mass ratio is more preferably 1.2% by mass to 25% by mass, and still more preferably 1.5% by mass to 20% by mass. If the mass ratio of the carbonaceous material is 1% or more by mass, the carbonaceous material can sufficiently increase the reaction sites with lithium ions, and desolvation of lithium ions becomes easy, thereby exhibiting high input / output characteristics. be able to. On the other hand, if the mass ratio of the carbonaceous material is 30% by mass or less, the in-solid diffusion of lithium ions between the carbonaceous material and the base material can be well maintained, and high input / output characteristics can be exhibited. In addition, since the charge and discharge efficiency of lithium ions can be improved, high cycle durability can be exhibited.

  The doping amount of lithium ion per unit mass of composite carbon material 2 is preferably 50 mAh / g to 700 mAh / g, more preferably 70 mAh / g to 650 mAh / g, and still more preferably 90 mAh / g to 600 mAh / G or less, particularly preferably 100 mAh / g or more and 550 mAh / g or less.

  Hereinafter, as a preferable example of the composite carbon material 2, a composite carbon material 2a in the case where a graphite material is used as a base material and a carbonaceous material is adhered to the base material will be described.

  The average particle diameter of the composite carbon material 2a is preferably 1 μm or more and 10 μm or less. The average particle size is more preferably 2 μm to 8 μm, and still more preferably 3 μm to 6 μm. When the average particle size is 1 μm or more, the charge and discharge efficiency of lithium ions can be improved, and high cycle durability can be exhibited. On the other hand, if it is 10 μm or less, the reaction area of the composite carbon material 2a and the non-aqueous electrolyte solution increases, so high input / output characteristics can be exhibited.

BET specific surface area of the composite carbon material 2a is preferably from ^{1 m} 2 / g or more ^{50 m} 2 / g, more preferably at most ^{1 m} 2 / g or more ^{20 m} 2 / g, more preferably ^{1 m} 2 / g 15 m ² / g or less, 1.5 m ² / g or more and 15 m ² / g or less, or 2 m ² / g or more and 15 m ² / g or less. If this BET specific surface area is 1 m ² / g or more, a reaction site with lithium ions can be sufficiently secured, and high input / output characteristics can be exhibited. On the other hand, when the BET specific surface area is 20 m ² / g or less, the charge / discharge efficiency of lithium ions is improved, and the decomposition reaction of the non-aqueous electrolyte solution during charge / discharge is suppressed, thereby exhibiting high cycle durability. Can.

  As a graphite material used as a substrate of composite carbon material 2a, as long as composite carbon material 2a obtained shows desired characteristics, there is no restriction in particular. For example, artificial graphite, natural graphite, graphitized mesophase carbon microspheres, graphite whiskers and the like can be used. The average particle size of the graphite material is preferably 1 μm to 10 μm, more preferably 2 μm to 8 μm.

The functions and specific examples of the carbonaceous material precursor used as the carbon source of the carbonaceous material to be deposited on the substrate in the composite carbon material 2a are the same as those of the carbonaceous material precursor in the composite carbon material 1a.
The mass ratio of the carbonaceous material to the graphite material in the composite carbon material 2a is preferably 1% by mass or more and 10% by mass or less. The mass ratio is more preferably 1.2% to 8% by mass, still more preferably 1.5% to 6% by mass, and particularly preferably 2% to 5% by mass. If the mass ratio of the carbonaceous material is 1% by mass or more, the reactive site with lithium ions can be sufficiently increased by the carbonaceous material, and desolvation of lithium ions becomes easy, thereby exhibiting high input / output characteristics. be able to. On the other hand, if the mass ratio of the carbonaceous material is 10% by mass or less, the in-solid diffusion of lithium ions between the carbonaceous material and the graphite material can be well maintained, and high input / output characteristics can be exhibited. In addition, since the charge and discharge efficiency of lithium ions can be improved, high cycle durability can be exhibited.

-Anode active materials other than carbon materials-
Specific examples of the negative electrode active material other than the carbon material in the present embodiment include titanium oxide, silicon, silicon oxide, silicon alloy, silicon compound, tin, tin compound and the like.

(Other components of negative electrode active material layer)
The negative electrode active material layer in the present embodiment may optionally contain, in addition to the negative electrode active material, optional components such as a conductive filler, a binder, and a dispersion stabilizer.
-Conductive filler-
Although the kind in particular of a conductive filler is not restrict | limited, For example, acetylene black, ketjen black, a vapor growth carbon fiber etc. are illustrated. The amount of the conductive filler used is preferably 0 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. More preferably, it is 0 parts by mass or more and 20 parts by mass or less, still more preferably 0 parts by mass or more and 15 parts by mass or less.

-Binder-
The binder is not particularly limited. For example, PVdF (polyvinylidene fluoride), PTFE (polytetrafluoroethylene), polyimide, latex, styrene-butadiene copolymer, fluororubber, acrylic copolymer Etc. can be used. The amount of the binder used is preferably 1 to 30 parts by mass, more preferably 2 to 27 parts by mass, and still more preferably 3 to 1 part by mass with respect to 100 parts by mass of the negative electrode active material. It is 25 parts by mass or less. When the amount of the binder is 1 part by mass or more, sufficient electrode strength is developed. On the other hand, when the amount of the binder is 30 parts by mass or less, high input / output characteristics are exhibited without inhibiting the lithium ion from entering and leaving the negative electrode active material.

-Dispersion stabilizer-
The dispersion stabilizer is not particularly limited, and for example, PVP (polyvinyl pyrrolidone), PVA (polyvinyl alcohol), a cellulose derivative and the like can be used. The use amount of the dispersion stabilizer is preferably 0 parts by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the negative electrode active material. If the amount of the dispersion stabilizer is 10 parts by mass or less, high input / output characteristics are exhibited without inhibiting the lithium ion from entering and exiting from the negative electrode active material.

[Manufacture of negative electrode]
The negative electrode is formed by providing a negative electrode active material layer on one side or both sides of a negative electrode current collector. In a typical embodiment, the negative electrode active material layer is fixed to the negative electrode current collector.
The negative electrode can be manufactured by a known manufacturing technique of an electrode in a lithium ion battery, an electric double layer capacitor and the like. For example, various materials containing a negative electrode active material are dispersed or dissolved in water or an organic solvent to prepare a slurry-like coating liquid, and this coating liquid is coated on one side or both sides on a negative electrode current collector. A negative electrode can be obtained by forming a coating and drying it. Furthermore, the obtained negative electrode may be pressed to adjust the film thickness or bulk density of the negative electrode active material layer. Alternatively, various materials containing the negative electrode active material are dry mixed without using a solvent, and the obtained mixture is press-formed and then attached to the negative electrode current collector using a conductive adhesive. Is also possible.
Hereinafter, the manufacturing method of the negative electrode using a coating liquid is demonstrated.

(Coating solution)
The coating liquid contains a negative electrode active material and a solvent, and may further contain optional additional components such as a binder and a dispersant.
The preparation of the coating solution may be performed, for example, by dry blending all the materials including the negative electrode active material and then adding water or an organic solvent;
After dry blending a part of the material containing the negative electrode active material and adding water or an organic solvent, prepare a solution or slurry in which the remaining material containing the binder, dispersion stabilizer, etc. is dissolved or dispersed. May be; or
The remaining material including the negative electrode active material may be additionally prepared in a solution or slurry in which a binder, a dispersion stabilizer, and the like are dissolved or dispersed in water or an organic solvent.

  The method for dissolving or dispersing the material powder in water or an organic solvent is not particularly limited, but preferably, a homodisper is a dispersion such as a multiaxial disperser, a planetary mixer, a thin film swirling high speed mixer, etc. A machine etc. can be used. In order to obtain a coating liquid in a well-dispersed state, it is preferable to disperse at a circumferential speed of 1 m / s or more and 50 m / s or less. If the circumferential speed is 1 m / s or more, various materials are preferably dissolved or dispersed well. In addition, if the circumferential velocity is 50 m / s or less, various materials are not broken even by heat or shear force caused by dispersion, and reagglomeration does not occur, which is preferable.

The viscosity (ηb) of the coating liquid is preferably 1,000 mPa · s or more and 20,000 mPa · s or less, more preferably 1,500 mPa · s or more and 10,000 mPa · s or less, still more preferably 1,700 mPa · s or more It is 5,000 mPa · s or less. If the viscosity (ηb) is 1,000 mPa · s or more, dripping during coating film formation can be suppressed, and the coating film width and film thickness can be favorably controlled. Moreover, if it is 20,000 mPa · s or less, the pressure loss in the flow path of the coating liquid when using a coating machine is small, coating can be stably performed, and control can be performed to a desired coating film thickness.
The TI value (thixotropy index value) of the coating liquid is preferably 1.1 or more, more preferably 1.2 or more, and still more preferably 1.5 or more. If the TI value is 1.1 or more, the coating film width and the film thickness can be controlled well.

(Coating method)
The formation of the coating film is not particularly limited, but can preferably be performed using a coating machine such as a die coater, a comma coater, a knife coater, or a gravure coating machine. The coating film may be formed by single-layer coating or may be formed by multilayer coating. The coating speed is preferably 0.1 m / min to 100 m / min, more preferably 0.5 m / min to 70 m / min, and still more preferably 1 m / min to 50 m / min. If the coating speed is 0.1 m / min or more, stable coating can be performed. On the other hand, if the coating speed is 100 m / min or less, sufficient coating accuracy can be ensured.

(Drying of coating film)
The coating film obtained by traveling may then be dried (solvent removal).
Although the drying method in particular of a coating film is not restrict | limited, Drying methods, such as hot-air drying and infrared rays (IR) drying, can be used suitably, for example. The coating may be dried at a single temperature, or may be dried by changing the temperature in multiple stages or gradually. Also, a plurality of drying methods may be combined and dried.
The drying temperature is preferably 25 ° C. or more and 200 ° C. or less, more preferably 40 ° C. or more and 180 ° C. or less, and still more preferably 50 ° C. or more and 160 ° C. or less. If the drying temperature is 25 ° C. or more, the solvent in the coating can be sufficiently volatilized. On the other hand, if the drying temperature is 200 ° C. or less, it is possible to suppress uneven distribution of the binder due to cracking or migration of the coating due to rapid evaporation of the solvent and oxidation of the negative electrode current collector or the negative electrode active material layer.
The drying time may be appropriately adjusted according to the thickness of the coating, the boiling point of the solvent, and the like.

(press)
The negative electrode obtained by drying the coated film may be further pressed to adjust the thickness, bulk density and the like of the negative electrode active material layer. The method of pressing the negative electrode is not particularly limited, but may preferably be performed using a press such as a hydraulic press, a vacuum press, a roll press, or the like. The film thickness, bulk density, and electrode strength of the negative electrode active material layer can be adjusted by the press pressure, the gap, the surface temperature of the press portion, and the like. The pressing pressure is preferably 0.5 kN / cm to 20 kN / cm, more preferably 1 kN / cm to 10 kN / cm, and still more preferably 2 kN / cm to 7 kN / cm. If the pressing pressure is 0.5 kN / cm or more, the electrode strength can be sufficiently high. On the other hand, if the press pressure is 20 kN / cm or less, deflection or wrinkles do not occur in the negative electrode, and the thickness and bulk density of the desired negative electrode active material layer can be adjusted. Further, the gap between the press rolls can be set to any value according to the thickness of the negative electrode film after pressing so that the desired thickness and bulk density of the negative electrode active material layer can be obtained. Furthermore, the pressing speed can be set to any speed that does not cause deflection or wrinkles on the negative electrode. In addition, the surface temperature of the press part may be room temperature or may be heated as required. The lower limit of the surface temperature of the press portion when heating is preferably 60 ° C. or higher, more preferably 45 ° C. or higher, and still more preferably 30 ° C. or higher. On the other hand, the upper limit of the surface temperature of the press part in heating is preferably the melting point of the binder to be used plus 50 ° C. or less, more preferably 30 ° C. or less, still more preferably 20 ° C. or less. For example, when PVdF (polyvinylidene fluoride: melting point 150 ° C.) is used as the binder, the temperature is preferably 90 ° C. or more and 200 ° C. or less, more preferably 105 ° C. or more and 180 ° C. or less, still more preferably 120 ° C. or more It is to heat at 170 degrees C or less. When a styrene-butadiene copolymer (melting point 100 ° C.) is used as the binder, the temperature is preferably 40 ° C. to 150 ° C., more preferably 55 ° C. to 130 ° C., further preferably 70. C. to 120.degree. C. or less.

  The melting point of the binding agent can be determined at the endothermic peak position of DSC (Differential Scanning Calorimetry, differential scanning calorimetry). For example, 10 mg of the sample resin is set in the measurement cell using a differential scanning calorimeter “DSC 7” manufactured by Perkin Elmer, and the temperature is increased from 30 ° C. to 10 ° C./min up to 250 ° C. in a nitrogen gas atmosphere. The temperature is raised, and the endothermic peak temperature in the temperature raising process becomes the melting point.

  The pressing may be performed multiple times while changing the conditions of the pressing pressure, the gap, the speed, and the surface temperature of the pressing unit.

[XPS analysis of negative electrode active material layer surface]
In the negative electrode active material layer according to this embodiment, the element concentration of S determined based on the peak area of 168 eV of the S2p spectrum obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the negative electrode active material layer is S _{168 eV} (atomic And the element concentration ratio S _{168 eV} / F _{685 eV} is 0.025 or more and 0.5 or less, where F _{685 eV} (atomic%) is the element concentration of F determined based on the peak area of 685 eV in the F1s spectrum. Is more preferably 0.08 or more and 0.3 or less. If this value is 0.025 or more, the suppression effect of the gas generated by the reductive decomposition of the non-aqueous electrolytic solution is exhibited. If this value is 0.5 or less, it is possible to suppress the initial resistance and the increase in resistance at high voltage and high temperature storage.

It is considered that the above-mentioned peak which the surface of the negative electrode active material layer of the present embodiment shows in XPS is caused by the film formed by the action of the sulfur-containing compound on the surface of the negative electrode active material layer.
As a method for causing the above-mentioned peak to appear on the surface of the negative electrode active material layer in the present embodiment in the XPS measurement, for example,
A method of mixing a sulfur-containing compound in the negative electrode active material layer,
A method of adsorbing a sulfur-containing compound to the negative electrode active material layer,
The method etc. which electrochemically deposit a sulfur-containing compound in a negative electrode active material layer are mentioned.
In particular, the non-aqueous electrolyte solution contains a specific precursor of the above-mentioned sulfur-containing compound, and the decomposition reaction in the process of manufacturing the non-aqueous lithium-type storage element of the present embodiment is used The preferred method is to deposit a film containing the decomposition product of the above-mentioned sulfur-containing compound precursor on the surface of the layer. In particular, the method of depositing the film through the process of oxidizing and decomposing an alkali metal compound in the positive electrode precursor at a high potential, which will be described later, is not clear in principle, but maintains high input / output characteristics even in a low temperature environment It is more preferable because a coating capable of

  The sulfur-containing compound precursor that causes the above peak shown in XPS of the surface of the negative electrode active material layer to be expressed is selected from compounds represented by chemical formulas (2-1) to (2-5) described later. It is preferable to use a sulfur-containing compound and to contain this in the electrolytic solution.

<Positive electrode>
The positive electrode has a positive electrode current collector and a positive electrode active material layer present on one side or both sides thereof.
The positive electrode active material layer preferably contains activated carbon as a positive electrode active material, and preferably further contains an alkali metal compound.
The positive electrode active material layer preferably includes activated carbon as a positive electrode active material, and the positive electrode active material layer preferably further includes an alkali metal compound at the stage of the “positive electrode precursor” before the lithium doping step. As described later, in this embodiment, the alkali metal compound in the positive electrode active material layer of the positive electrode precursor functions as a pre-doping source of lithium ions to the negative electrode in the storage element assembly process.
In the present specification, a positive electrode containing a predetermined alkali metal compound before the lithium doping step is referred to as a "positive electrode precursor", and a positive electrode after the lithium doping step is simply referred to as a "positive electrode".

[Positive current collector]
The material constituting the positive electrode current collector in the present embodiment is not particularly limited as long as it is a material having high electron conductivity and which does not cause deterioration due to elution to the electrolytic solution, reaction with electrolyte or ions, etc. Foil is preferred. An aluminum foil is particularly preferable as the positive electrode current collector in the non-aqueous lithium-type storage element of the present embodiment.
The metal foil used as the positive electrode current collector may be a normal smooth surface metal foil having no unevenness or through holes, or a metal having an unevenness subjected to embossing, chemical etching, electrolytic deposition, blasting, etc. It may be a foil, or a metal foil having through holes such as an expanded metal, a punching metal, and an etching foil.
From the viewpoint of electrode preparation easiness and high electron conductivity, the positive electrode current collector in the present embodiment is preferably non-porous.
The thickness of the positive electrode current collector is not particularly limited as long as the shape and strength of the positive electrode can be sufficiently maintained, but for example, 1 to 100 μm is preferable.

[Positive electrode active material layer]
The positive electrode active material layer in the positive electrode contains a positive electrode active material.
The positive electrode active material layer may contain other optional components such as a transition metal oxide, a conductive filler, a binder, and a dispersion stabilizer, as necessary, in addition to the positive electrode active material.
Further, it is preferable that the positive electrode active material layer of the positive electrode precursor further contains an alkali metal compound other than the positive electrode active material.

(Positive electrode active material)
The positive electrode active material contains activated carbon.
As the positive electrode active material, only activated carbon may be used, or in addition to the activated carbon, another positive electrode active material may be used in combination. As this other positive electrode active material, carbon materials other than activated carbon, a transition metal oxide, etc. can be mentioned, for example.

-Activated carbon-
There are no particular restrictions on the type of activated carbon used as the positive electrode active material and the raw materials therefor. However, in order to achieve both high input / output characteristics and high energy density, it is preferable to optimally control the pores of the activated carbon. Specifically, the amount of mesopores derived from pores with a diameter of 20 Å or more and 500 Å or less calculated by the BJH method is V1 (cc / g), and the amount of micropores derived from pores with a diameter of less than 20 Å calculated by the MP method When V2 (cc / g),
(1) For high input / output characteristics, 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the specific surface area measured by the BET method is 1,500 m ² Preferred is activated carbon (hereinafter also referred to as "activated carbon 1") which is at least / g and at most 3,000 m ² / g, and
(2) In order to obtain a high energy density, 0.8 <V1 ≦ 2.5 and 0.8 <V2 ≦ 3.0 are satisfied, and the specific surface area measured by the BET method is 2,300 m ² Activated carbon (hereinafter also referred to as “activated carbon 2”) which is at least / g and at most 4,000 m ² / g is preferable.

  Hereinafter, the above (1) activated carbon 1 and the above (2) activated carbon 2 will be described individually one by one.

(1) Activated carbon 1
The mesopore amount V1 of the activated carbon 1 is preferably a value larger than 0.3 cc / g from the viewpoint of increasing the input / output characteristics when incorporated into the storage element. On the other hand, it is preferable that it is 0.8 cc / g or less from a viewpoint of suppressing the fall of the bulk density of a positive electrode. The V1 is more preferably 0.35 cc / g or more and 0.7 cc / g or less, and further preferably 0.4 cc / g or more and 0.6 cc / g or less.
The micropore amount V2 of the activated carbon 1 is preferably 0.5 cc / g or more in order to increase the specific surface area of the activated carbon and to increase the capacity. On the other hand, it is preferable that it is 1.0 cc / g or less from a viewpoint of suppressing the bulk of activated carbon, increasing the density as an electrode, and increasing the capacity per unit volume. The V2 is more preferably 0.6 cc / g or more and 1.0 cc / g or less, still more preferably 0.8 cc / g or more and 1.0 cc / g or less.

  The ratio (V1 / V2) of the amount of mesopores V1 to the amount of micropores V2 is preferably in the range of 0.3 ≦ V1 / V2 ≦ 0.9. That is, V1 / V2 is preferably 0.3 or more from the viewpoint of increasing the ratio of the amount of mesopores to the amount of micropores to such an extent that the decrease in output characteristics can be suppressed while maintaining a high capacity. On the other hand, V1 / V2 is preferably 0.9 or less from the viewpoint of increasing the ratio of the amount of micropores to the amount of mesopores to such an extent that the decrease in capacity can be suppressed while maintaining high output characteristics. . The more preferable range of V1 / V2 is 0.4 ≦ V1 / V2 ≦ 0.7, and the more preferable range of V1 / V2 is 0.55 ≦ V1 / V2 ≦ 0.7.

  The average pore diameter of the activated carbon 1 is preferably 17 Å or more, more preferably 18 Å or more, and most preferably 20 Å or more, from the viewpoint of maximizing the output of the obtained storage element. Further, from the viewpoint of maximizing the capacity, the average pore diameter of the activated carbon 1 is preferably 25 Å or less.

BET specific surface area of the activated carbon 1 is preferably from 1,500 m ² / g or more 3,000 m ² / g, more preferably not more than 1,500 m ² / g or more 2,500 m ² / g. When the BET specific surface area is 1,500 m ² / g or more, good energy density is easily obtained, while when the BET specific surface area is 3,000 m ² / g or less, the strength of the electrode is maintained. The performance per electrode volume is increased since it is not necessary to incorporate a large amount of binder.

The average particle size of the activated carbon 1 is preferably 2 to 20 μm.
When the average particle diameter is 2 μm or more, the density per unit volume of the electrode tends to be high because the density of the active material layer is excessively high. Here, if the average particle size is small, the defect that the durability is low may be caused, but if the average particle size is 2 μm or more, such a defect hardly occurs. On the other hand, when the average particle diameter is 20 μm or less, it tends to be easily adapted to high-speed charge and discharge. The average particle size is more preferably 2 to 15 μm, and still more preferably 3 to 10 μm.

The activated carbon 1 having the characteristics as described above can be obtained, for example, using the raw material and the treatment method described below.
In the present embodiment, the carbon source used as the raw material of the activated carbon 1 is not particularly limited. For example, plant materials such as wood, wood flour, coconut husk, pulp by-products, bagasse, waste molasses, etc .; peat, lignite, lignite, bituminous coal, anthracite, petroleum distillation residue components, petroleum pitch, coke, coal tar, etc. Fossil materials; Various synthetic resins such as phenol resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, urea resin, resorcinol resin, celluloid, epoxy resin, polyurethane resin, polyester resin, polyamide resin, etc .; polybutylene, polybutadiene, polychloroprene etc. And other synthetic wood, synthetic pulp and the like, and carbides thereof. Among these raw materials, from the viewpoint of mass production and cost, plant-based raw materials such as coconut husk and wood flour, and their carbides are preferable, and coconut husk carbide is particularly preferable.

As methods of carbonization and activation for making these raw materials into activated carbon 1, for example, known methods such as fixed bed method, moving bed method, fluidized bed method, slurry method, rotary kiln method can be adopted.
As carbonization methods of these raw materials, inert gases such as nitrogen, carbon dioxide, helium, argon, xenon, neon, carbon monoxide, combustion exhaust gas, or other gases mainly composed of these inert gases There is a method of using a mixed gas and firing at about 400 to 700 ° C. (preferably 450 to 600 ° C.) for about 30 minutes to 10 hours.

As an activation method of the carbide obtained by the above carbonization method, a gas activation method of firing using an activation gas such as water vapor, carbon dioxide, oxygen and the like is preferably used. Among these, the method of using steam or carbon dioxide as the activating gas is preferable.
In this activation method, while supplying the activation gas at a rate of 0.5 to 3.0 kg / h (preferably 0.7 to 2.0 kg / h), the above carbide is kept for 3 to 12 hours (preferably 5 to 11). Preferably, the temperature is raised to 800 ° C. to 1,000 ° C. for activation over a period of time, more preferably 6 to 10 hours.
Furthermore, prior to the activation treatment of the carbide, the carbide may be primary activated in advance. In this primary activation, a method in which a carbon material is fired at a temperature of less than 900 ° C. by using an activating gas such as water vapor, carbon dioxide, oxygen and the like can be preferably employed.
The activated carbon 1 having the above characteristics, which can be used in the present embodiment, is produced by appropriately combining the firing temperature and the firing time in the above carbonization method with the activation gas supply amount, the temperature raising rate and the maximum activation temperature in the above activation method. can do.

(2) Activated carbon 2
The amount of mesopores V1 of the activated carbon 2 is preferably a value larger than 0.8 cc / g from the viewpoint of increasing the output characteristics when incorporated into the storage element. On the other hand, V1 is preferably 2.5 cc / g or less from the viewpoint of suppressing a decrease in capacity of the storage element. The V1 is more preferably 1.00 cc / g or more and 2.0 cc / g or less, and further preferably 1.2 cc / g or more and 1.8 cc / g or less.

  The micropore amount V2 of the activated carbon 2 is preferably a value larger than 0.8 cc / g in order to increase the specific surface area of the activated carbon and to increase the capacity. On the other hand, V2 is preferably 3.0 cc / g or less from the viewpoint of increasing the density of activated carbon as an electrode and increasing the capacity per unit volume. V2 is more preferably 1.0 cc / g or more and 2.5 cc / g or less, and further preferably 1.5 cc / g or more and 2.5 cc / g or less.

The activated carbon 2 having the amount of mesopores and the amount of micropores described above has a BET specific surface area higher than that of the activated carbon used for conventional electric double layer capacitors or lithium ion capacitors. The specific value of the BET specific surface area of the activated carbon 2 is preferably 2,300 m ² / g or more and 4,000 m ² / g or less. The lower limit of the BET specific surface area is more preferably 3,000 m ² / g or more, and still more preferably 3,200 m ² / g or more. On the other hand, the upper limit of the BET specific surface area is more preferably 3,800 m ² / g or less. When the BET specific surface area is 2300 m ² / g or more, good energy density is easily obtained, while when the BET specific surface area is 4,000 m ² / g or less, the strength of the electrode is maintained. The performance per electrode volume is increased since it is not necessary to incorporate a large amount of binder.

The activated carbon 2 having the characteristics as described above can be obtained, for example, using a raw material and a treatment method as described below.
The carbon source used as the raw material of the activated carbon 2 is not particularly limited as long as it is a carbon source generally used as the activated carbon raw material, for example, plant-based raw materials such as wood, wood flour, coconut shell; petroleum pitch, coke Etc .; various synthetic resins such as phenol resin, furan resin, vinyl chloride resin, vinyl acetate resin, melamine resin, urea resin, resorcinol resin and the like. Among these raw materials, phenolic resins and furan resins are particularly suitable for producing activated carbon having a high specific surface area.

  Examples of a method of carbonizing the raw materials or a heating method at the time of activation treatment include known methods such as a fixed bed method, a moving bed method, a fluidized bed method, a slurry method, and a rotary kiln method. As an atmosphere at the time of heating, an inert gas such as nitrogen, carbon dioxide, helium, argon or the like, or a mixed gas containing such an inert gas as a main component and mixed with another gas is used. The carbonization temperature is about 400 ° C. to 700 ° C. (the lower limit is preferably 450 ° C. or more, more preferably 500 ° C. or more. The upper limit is preferably 650 ° C.), and baking may be performed for about 0.5 to 10 hours. preferable.

As a method of activating carbides after the above carbonization treatment, a gas activation method in which carbides are fired using an activating gas such as water vapor, carbon dioxide, oxygen, etc .; and heat treatment is performed after mixing carbides with an alkali compound, alkali activation There is a law. Among these, in order to produce activated carbon having a high specific surface area, an alkali activation method is preferable.
In this activation method, after mixing so that the mass ratio of the carbide and the alkali compound such as KOH or NaOH is 1: 1 or more (the amount of the alkali compound is equal to or larger than the amount of the carbide), Heating is carried out in an inert gas atmosphere in a range of 600 ° C. to 900 ° C. (preferably 650 ° C. to 850 ° C.) for 0.5 to 5 hours, and then the alkali compound is washed away with acid and water, and further Do the drying.

When the carbide and the alkali compound are mixed, the amount of mesopores increases as the ratio of the alkali compound increases, but the amount of pores tends to increase rapidly at a mass ratio of about 1: 3.5. Therefore, the mass ratio of the carbide to the alkali compound is preferably a ratio in which the amount of the alkali compound is more than 1: 3, and it is preferable that the mass ratio is 1: 5.5 or less. This mass ratio increases in the amount of pores as the amount of the alkali compound increases, but is preferably in the above range in consideration of the processing efficiency of subsequent washing and the like.
In order to increase the amount of micropores and not to increase the amount of mesopores, it is preferable to increase the amount of carbide and mix with the alkali compound when activating. In order to increase both the amount of micropores and the amount of mesopores, it is preferable to use more alkali compound. Moreover, in order to mainly increase the amount of mesopores, it is preferable to further perform steam activation after the alkali activation treatment.
The average particle diameter of the activated carbon 2 is preferably 2 μm or more and 20 μm or less, more preferably 3 μm or more and 10 μm or less.

(3) Use Mode of Activated Carbon The activated carbons 1 and 2 may each be composed of one kind of activated carbon, or a mixture of two or more kinds of activated carbon, and each characteristic value described above is a mixture as a whole It may be shown.
The above activated carbons 1 and 2 may be used by selecting any one of them, or may be used by mixing both.

-Positive electrode active material other than activated carbon-
The positive electrode active material may be composed only of activated carbons 1 and 2 or active carbons 1 and 2 and other positive electrode active materials (for example, activated carbon not having V ₁ and / or V ₂ specified above, or Carbon materials other than activated carbon and positive electrode active materials other than carbon materials may be included. In the illustrated embodiment, the total content of the activated carbons 1 and 2 is preferably more than 50% by mass, more preferably 70% by mass or more, of the total positive electrode active material. The total content of activated carbons 1 and 2 can be 100% by mass of the entire positive electrode active material. However, the content of the total of activated carbons 1 and 2 is preferably, for example, 90% by mass or less, from the viewpoint of obtaining the effect by combined use with other materials, for example, lithium transition metal oxide.

  As carbon materials other than activated carbon used as a positive electrode active material in the present embodiment, for example, carbon nanotubes, conductive polymers, or porous carbon materials are preferably used.

Examples of the positive electrode active material other than the carbon material used as the positive electrode active material in the present embodiment include, for example, transition metal oxides capable of inserting and extracting lithium ions.
The transition metal oxide is not particularly limited, but is preferably a transition metal oxide having a structure selected from a layered structure, an olivine structure, and a spinel structure.
In the present embodiment, if the positive electrode precursor contains an alkali metal compound different from the positive electrode active material, the alkali metal compound becomes a lithium ion dopant source by lithium doping described later, and the negative electrode can be pre-doped. Therefore, even if the transition metal compound does not contain lithium ions in advance, electrochemical charging and discharging can be performed as a non-aqueous lithium storage element after the lithium doping process. However, as the transition metal oxide in the present embodiment, an oxide having a lithium element and a transition metal element is preferable. Examples of the transition metal element in this case include at least one selected from the group consisting of cobalt, nickel, manganese, iron, vanadium, and chromium.

As preferable transition metal oxides in the present embodiment, specifically, for example, Li _x CoO ₂ , Li _x NiO ₂ , Li _x Ni _y M _(1-y) O ₂ (M is Co, Mn, Al, Fe) At least one element selected from the group consisting of Mg, and Ti, y satisfies 0.2 <y <0.97), Li _x Ni _1/3 Co _1/3 Mn _1/3 O ₂ , Li _x MnO ₂ , α-Li _x FeO ₂ , Li _x VO ₂ , Li _x CrO ₂ , Li _x FePO ₄ , Li _x MnPO ₄ , Li _z V ₂ (PO ₄ ) ₃ , Li _x Mn ₂ O ₄ , Li _x M _y Mn _(2-y) O ₄ (M is at least one element selected from the group consisting of Co, Mn, Al, Fe, Mg, and Ti, and y is 0.2 <y < satisfy 0.97.), _Li x Ni _{Co b Al (1-a-} b) O 2 (a and b satisfies 0.2 <a <0.97,0.2 <b < 0.97.), Li x Ni c Co d Mn (1 _{-c-d) O} 2 (c and d satisfy 0.2 <c <0.97,0.2 <d < 0.97.) and the like.
In the above, x satisfies 0 ≦ x ≦ 1, and z satisfies 0 ≦ z ≦ 3.

(Alkali metal compound)
The alkali metal compound preferably contained in the positive electrode active material layer in the present embodiment is a lithium compound from the viewpoint of being able to be decomposed at the positive electrode in the lithium doping step described later to release lithium ions. Specifically, for example, lithium carbonate, lithium oxide, lithium hydroxide, lithium fluoride, lithium chloride, lithium oxalate, lithium iodide, lithium iodide, lithium nitride, lithium oxalate, lithium acetate, lithium carbonate, sodium carbonate, potassium carbonate, carbonate One or more selected from the group consisting of rubidium and cesium carbonate are preferably used. Among them, one or more selected from the group consisting of lithium carbonate, lithium oxide and lithium hydroxide is more preferable, and lithium carbonate is more preferable from the viewpoint of handling in air and low hygroscopicity. .
Such an alkali metal compound is decomposed by the application of a voltage and functions as a lithium-doped dopant source to the negative electrode, and also forms pores in the positive electrode active material layer, so it has excellent electrolyte retention and ion conductivity. It is possible to form a positive electrode excellent in the properties.

(1) Alkali Metal Compound in Positive Electrode Precursor The positive electrode active material layer formed on the positive electrode current collector in the positive electrode precursor of the present embodiment preferably contains an alkali metal compound other than the positive electrode active material. . The alkali metal compound may be contained in any manner in the positive electrode active material layer of the positive electrode precursor. For example, the alkali metal compound may be present between the positive electrode current collector and the positive electrode active material layer, may be present on the surface of the positive electrode active material layer, or is present inside the positive electrode active material layer. It may be The alkali metal compound is preferably contained in the inside of the positive electrode active material layer formed on the positive electrode current collector of the positive electrode precursor.

  The alkali metal compound is preferably in the form of particles. The average particle size of the alkali metal compound contained in the positive electrode precursor is preferably 0.1 μm or more and 100 μm or less. The upper limit of the average particle size is more preferably 50 μm or less, still more preferably 20 μm or less, and most preferably 10 μm or less. On the other hand, the lower limit of the average particle size is more preferably 0.1 μm or more, still more preferably 0.5 μm or more. If the average particle size of the alkali metal compound is 0.1 μm or more, the pores remaining after the decomposition reaction of the alkali metal compound have a volume sufficient to hold the electrolytic solution at the positive electrode, so high load charging Discharge characteristics are improved. If the average particle size of the alkali metal compound is 100 μm or less, the surface area of the alkali metal compound does not become excessively small, so that the rate of decomposition reaction of the alkali metal compound can be secured.

  The alkali metal compound other than the positive electrode active material contained in the positive electrode precursor is preferably 1% by mass or more and 50% by mass or less based on the total mass of the positive electrode active material layer in the positive electrode, and is 2.5% by mass or more It is more preferable that it is 25 mass% or less. When the amount of the alkali metal compound is 1% by mass or more, a sufficient amount of lithium ions can be doped to the negative electrode in a lithium doping step described later. When the amount of the alkali metal compound is 50% by mass or less, the lithium ion doping amount to the negative electrode is suppressed from being excessively large, and the volume of the pores remaining after the decomposition reaction of the alkali metal compound is excessively large. Therefore, the strength of the positive electrode active material layer can be maintained.

(2) Alkali metal compound of positive electrode It is preferable that the positive electrode active material layer formed on the positive electrode current collector in the positive electrode of the present embodiment contains an alkali metal compound other than the positive electrode active material.
Assuming that the average particle diameter of an alkali metal compound other than the positive electrode active material contained in the positive electrode is X ₁ and the average particle diameter of the positive electrode active material is Y ₁ , 0.1 μm ≦ X ₁ ≦ 10 μm, 2 μm ≦ Y It is preferable that ₁ ≦ 20 μm and X ₁ <Y ₁ . More preferably, X ₁ is 0.5 μm ≦ X ₁ ≦ 5 μm. When X ₁ is 0.1 μm or more, high load charge / discharge cycle characteristics are improved by adsorbing fluorine ions generated in the high load charge / discharge cycle. When X ₁ is 10 μm or less, the reaction area with the fluorine ions generated in the high load charge-discharge cycle is increased, so that the fluorine ions can be adsorbed efficiently. When Y ₁ is 2 μm or more, electron conductivity between positive electrode active materials can be secured. When Y ₁ is 20 μm or less, high output characteristics can be exhibited because the reaction area with electrolyte ions increases. In the case of X ₁ <Y ₁ , since the alkali metal compound is filled in the gaps formed between the positive electrode active materials, the energy density can be increased while securing the electron conductivity between the positive electrode active materials.

  The alkali metal compound other than the positive electrode active material contained in the positive electrode is preferably 1% by mass or more and 50% by mass or less, based on the total mass of the positive electrode active material layer in the positive electrode, and is 2.5% by mass or more and 25% by mass. It is more preferable that the content is less than%. When the amount of the alkali metal compound is 1% by mass or more, lithium carbonate suppresses the decomposition reaction of the electrolyte solvent on the positive electrode in a high temperature environment, so the high temperature durability is improved, and is 2.5% by mass or more And, the effect becomes remarkable. Further, when the amount of the alkali metal compound is 50% by mass or less, the electron conductivity between the positive electrode active materials is relatively small to be inhibited by the alkali metal compound, so high input / output characteristics are exhibited. If there is, high input / output characteristics become noticeable.

-Analysis method of alkali metal compound in positive electrode or positive electrode precursor-
(1) Qualitative analysis The identification method of the alkali metal compound contained in a positive electrode active material layer is not specifically limited. For example, SEM-EDX (scanning electron microscope-energy dispersive X-ray analysis), microscopic Raman analysis, XPS, solid ⁷ Li-NMR, XRD (X-ray diffraction), TOF-SIMS (time-of-flight secondary ion mass spectrometry) Identification of alkali metal compounds by using one or more analysis methods selected from:), AES (Auger electron spectroscopy), TPD / MS (heating generated gas mass spectrometry), DSC (differential scanning calorimetry), etc. You can also.

(2) Quantitative Analysis The method for quantifying the alkali metal compound contained in the positive electrode or positive electrode precursor is described below.
The positive electrode or positive electrode precursor is washed with an organic solvent and then washed with distilled water, and the alkali metal compound can be quantified from the mass change of the positive electrode or positive electrode precursor before and after washing with distilled water.
The organic solvent for cleaning is not particularly limited as long as the decomposition product of the non-aqueous electrolytic solution deposited on the positive electrode surface can be removed, and an alkali metal compound having a solubility of 2% by mass or less is used. It is preferable because elution of the metal compound is suppressed. As an organic solvent for washing | cleaning, polar solvents, such as methanol and acetone, are used suitably, for example.

(Optional component of positive electrode active material layer)
The positive electrode active material layer in the present embodiment may optionally contain, in addition to the positive electrode active material and the alkali metal compound, optional components such as a conductive filler, a binder, and a dispersion stabilizer.
About these conductive fillers, a binder, and a dispersion stabilizer, the content demonstrated above as a conductive filler, a binder, and a dispersion stabilizer as an arbitrary component in a negative electrode active material layer is referred After replacing with "positive electrode", you may use suitably.

(Preferred embodiment of positive electrode active material layer)
Basis weight of the positive electrode active material layer in this embodiment is preferably a cathode current collector is 180 g / ^{m 2} or less per side 20 g / ^{m 2} or more, more preferably per surface 25 g / ^{m 2} or more 120 g / ^{m 2} or less And more preferably 30 g / m ² or more and 80 g / m ² or less. If this fabric weight is 20 g / m < ² > or more, sufficient charging / discharging capacity can be expressed. On the other hand, if this fabric weight is 180 g / m < ² > or less, the ion diffusion resistance in a positive electrode can be maintained low. Therefore, sufficient output characteristics can be obtained, and the cell volume can be reduced, so that the energy density of the obtained storage element can be increased.

  The thickness of the positive electrode active material layer is preferably 20 μm to 200 μm per side of the positive electrode current collector, more preferably 25 μm to 100 μm per side, and still more preferably 30 μm to 80 μm. If this thickness is 20 μm or more, sufficient charge and discharge capacity can be exhibited. On the other hand, if this thickness is 200 μm or less, the ion diffusion resistance in the positive electrode can be maintained low. Therefore, sufficient output characteristics can be obtained, and the cell volume can be reduced, so that the energy density of the obtained storage element can be increased. The thickness of the positive electrode active material layer in the case where the current collector has through holes or irregularities is the thickness per surface of the positive electrode active material layer in a portion having no through holes or irregularities in the current collector. Average value.

The bulk density of the positive electrode active material layer in the positive electrode after the later-described lithium doping step is preferably 0.25 g / cm ³ or more, more preferably in the range of 0.30 g / cm ³ or more and 1.3 g / cm ³ or less It is. If the bulk density of the positive electrode active material layer is 0.25 g / cm ³ or more, high energy density can be exhibited, and downsizing of the storage element can be achieved. On the other hand, when the bulk density is 1.3 g / cm ³ or less, the diffusion of the non-aqueous electrolytic solution in the pores in the positive electrode active material layer is sufficient, and high output characteristics can be obtained.

The BET specific surface area per unit area of the positive electrode current collector of the positive electrode active material layer in the present embodiment is preferably 0.2 m ² / cm ² or more and 10 m ² / cm ² or less. When the BET specific surface area is 0.2 m ² / cm ² or more, anions are easily adsorbed and desorbed, which results in a low resistance storage element. When the BET specific surface area is 10 m ² / cm ² or less, the oxidation reaction site is small. The generation of decomposition gas at high voltage can be suppressed.

[Manufacture of positive electrode]
The positive electrode in the non-aqueous lithium-type energy storage device of the present embodiment is a positive electrode precursor having a positive electrode active material layer containing a positive electrode active material and an alkali metal compound passes through a lithium doping process to obtain an alkali metal compound as a lithium ion to the negative electrode. It forms after utilizing as a pre dope source. Therefore, first, the production of the "positive electrode precursor" will be described below.

(Production of positive electrode precursor)
The positive electrode precursor comprises a positive electrode active material layer provided on one side or both sides of a positive electrode current collector. As described above, the positive electrode active material layer in the positive electrode precursor contains the positive electrode active material and the alkali metal compound. In a typical embodiment, the positive electrode active material layer is fixed to the positive electrode current collector.
In the present embodiment, the positive electrode precursor to be the positive electrode of the non-aqueous lithium-type storage element can be manufactured by a known manufacturing technique of an electrode in a lithium ion battery, an electric double layer capacitor or the like. For example, a positive electrode active material, an alkali metal compound, and other optional components used as needed are dispersed or dissolved in water or an organic solvent to prepare a slurry-like coating liquid, and this coating liquid is The positive electrode precursor can be obtained by coating on one side or both sides of the positive electrode current collector to form a coating, and drying it. Furthermore, the obtained positive electrode precursor may be pressed to adjust the thickness or bulk density of the positive electrode active material layer, or both of them. Alternatively, without using a solvent, the positive electrode active material and the alkali metal compound, and other optional components used as required, are dry mixed, and the resulting mixture is pressed and then conductive. It is also possible to use an adhesive to attach to the positive electrode current collector.
Hereinafter, the manufacturing method of the positive electrode precursor using a coating liquid is demonstrated.

(Coating solution)
The coating liquid of the positive electrode precursor contains a positive electrode active material and an alkali metal compound, and may further contain optional addition components such as a binder and a dispersant.
The preparation of the coating solution may be prepared, for example, by dry blending all materials including the positive electrode active material and the alkali metal compound, and then adding water or an organic solvent;
After dry blending a part of the material containing at least one of the positive electrode active material and the alkali metal compound and adding water or an organic solvent, the remaining material containing a binder, a dispersion stabilizer, etc. was dissolved or dispersed. The solution or slurry may be additionally prepared; or,
In the solution or slurry in which the binder, the dispersion stabilizer and the like are dissolved or dispersed in water or an organic solvent, the remaining material including at least one of the positive electrode active material and the alkali metal compound may be additionally prepared. .

In the above, in the dry blending, for example, the positive electrode active material and the alkali metal compound, and, if necessary, the conductive filler are premixed to make the low conductivity alkali metal compound coated with the conductive filler. You may Thereby, the alkali metal compound is easily decomposed in the positive electrode precursor in the lithium doping step described later. For example, a ball mill etc. can be used for this dry blending.
When water is used as a solvent for the coating solution, the coating solution may be made alkaline by the addition of an alkali metal compound. In such a case, a pH adjuster may be added to the coating liquid as necessary.
The preparation of the coating solution can be carried out in the same manner as the coating solution for the negative electrode.

  As for the degree of dispersion of the coating liquid, it is preferable that the particle size measured by the particle gauge be 0.1 μm or more and 100 μm or less. As the upper limit of the degree of dispersion, the particle size is more preferably 80 μm or less, still more preferably 50 μm or less. If the particle size is less than 0.1 μm, the particle size is smaller than the particle size at the time of preparation of various material powders including the positive electrode active material, and it is not preferable because the material needs to be crushed at the time of preparation of the coating liquid. In addition, when the particle size is 100 μm or less, the coating can be stably performed without clogging at the time of discharging the coating liquid, generation of streaks of the coating film, and the like.

  The viscosity (ηb) of the coating liquid of the positive electrode precursor, the TI value, the coating method, the method of drying the coating film, and the press optionally performed may be similar to the formation of the negative electrode active material layer.

[XPS analysis of surface of positive electrode active material layer]
In the positive electrode active material layer according to the present embodiment, the element concentration ratio S _{164 eV} / C obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the positive electrode active material layer is 0.001 or more and 0.05 or less. This value is preferably 0.004 or more and 0.01 or less.
If S _{164 eV} / C is 0.001 or more, the positive electrode film derived from the additive of the non-aqueous electrolytic solution is sufficient, so that generation of decomposition gas of electrolytic solution solvent at high voltage and high temperature storage is suppressed . When the S _{164 eV} / C is 0.05 or less, the initial resistance of the obtained storage element can be maintained low, and the increase in resistance at high voltage and high temperature storage can also be suppressed.

It is considered that the above-mentioned peak which the surface of the positive electrode active material layer of the present embodiment shows in XPS is caused by the film produced by the action of the compound having the C—S—C structure on the surface of the positive electrode active material layer.
Examples of the method for causing the above peak to appear on the surface of the positive electrode active material layer in the present embodiment during XPS measurement include, for example,
A method of mixing a compound having a C—S—C structure in the positive electrode active material layer,
A method of adsorbing a compound having a C—S—C structure to a positive electrode active material layer,
The method etc. which electrochemically precipitate the compound which has a C-S-C structure to a positive electrode active material layer are mentioned.
Among them, a positive electrode active material is obtained by using the decomposition reaction in the process of manufacturing the non-aqueous lithium-type energy storage device of the present embodiment by incorporating a specific compound having a C-S-C structure in the non-aqueous electrolytic solution. Preferred is a method of depositing a film containing a decomposition product of the above compound on the surface of the layer. In particular, the method of depositing the film through the step of oxidizing and decomposing an alkali metal compound in the positive electrode precursor described later at a high potential forms a film capable of maintaining high input / output characteristics even under a low temperature environment. More preferable.

  As a precursor of a compound having a C—S—C structure which causes the above peak shown in XPS on the surface of the positive electrode active material layer, a compound represented by the chemical formula (1) described later is used and contained in the electrolytic solution It is preferable to

<Separator>
The positive electrode precursor and the negative electrode are stacked via a separator to form an electrode laminate having the positive electrode precursor, the negative electrode and the separator, or stacked after being stacked via the separator, the positive electrode precursor, the negative electrode And an electrode winding body having a separator is formed.
As the separator, a microporous film made of polyethylene or a microporous film made of polypropylene used for a lithium ion secondary battery, a non-woven paper made of cellulose used for an electric double layer capacitor, etc. can be used. A film made of organic or inorganic fine particles may be laminated on one side or both sides of these separators. In addition, organic or inorganic fine particles may be contained inside the separator.
The thickness of the separator is preferably 5 μm or more and 35 μm or less. By setting the thickness to 5 μm or more, the self-discharge due to the internal micro short tends to be small, which is preferable. On the other hand, the thickness of 35 μm or less is preferable because the input / output characteristics of the non-aqueous lithium-type storage element tend to be high.
The thickness of the film made of organic or inorganic fine particles is preferably 1 μm to 10 μm. By setting this film to a thickness of 1 μm or more, it is preferable because the self-discharge due to the micro short in the separator tends to be small. On the other hand, by setting the thickness to 10 μm or less, the input / output characteristics of the non-aqueous lithium-type storage element tend to be high, which is preferable.

<Electrolyte solution>
The electrolytic solution in the non-aqueous lithium-type storage element of this embodiment is a non-aqueous electrolytic solution. That is, this electrolytic solution contains a non-aqueous solvent described later. The non-aqueous electrolyte preferably contains 0.5 mol / L or more of lithium salt based on the total amount of the non-aqueous electrolyte. That is, it is preferable that the non-aqueous electrolytic solution contains, as an electrolyte, lithium ions generated by ionizing this lithium salt.

[Lithium salt]
The non-aqueous electrolyte solution in the present embodiment is, for example, (LiN (SO ₂ F) ₂ ), LiN (SO ₂ CF ₃ ) ₂ , LiN (SO ₂ C ₂ F ₅ ) ₂ , LiN (SO ₂ ) as lithium salts. _{CF 3) (SO 2 C 2} F 5), LiN (SO 2 CF 3) (SO 2 C 2 F 4 H), LiC (SO 2 F) 3, LiC (SO 2 CF 3) 3, LiC (SO 2 It contains one or more selected from C ₂ F ₅ ) ₃ , LiCF ₃ SO ₃ , LiC ₄ F ₉ SO ₃ , LiPF ₆ , LiBF _{4 and the} like. These can be used alone or as a mixture of two or more.
The non-aqueous electrolyte preferably contains at least one selected from the group consisting of LiPF ₆ , LiN (SO ₂ F) ₂ , and LiBF ₄ because it can exhibit high conductivity, and LiPF ₆ and LiBF ₄ It is more preferable to contain one or more selected from the group consisting of and LiN (SO ₂ F) ₂ . LiN (SO ₂ F) ₂ can increase the ion conductivity of the non-aqueous electrolyte solution and reduce the generation of gas generated by decomposition of the electrolyte solution by depositing an appropriate amount of electrolyte film on the negative electrode / positive electrode interface. it can.

  The lithium salt concentration in the non-aqueous electrolyte solution is preferably 0.5 mol / L or more based on the total amount of the non-aqueous electrolyte solution, and a range of 0.5 mol / L or more and 2.0 mol / L or less is more preferable. . If the lithium salt concentration is 0.5 mol / L or more, the anions are sufficiently present, and the capacity of the storage element can be sufficiently increased. In addition, when the lithium salt concentration is 2.0 mol / L or less, it is possible to prevent the undissolved lithium salt from depositing in the non-aqueous electrolyte solution and to prevent the viscosity of the electrolyte solution from becoming too high, and the conductivity decreases. It is preferable because it does not cause deterioration of the output characteristics.

{式（１）中、Ｒ^１〜Ｒ^４はそれぞれ独立に、水素原子、ハロゲン原子、ホルミル基、炭素数２〜７のアシル基、ニトリル基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜７のアルキルカルボニルオキシ基、又は炭素数２〜７のアルキルオキシカルボニル基を表す。}

{式（２−１）〜（２−５）中のＲ^５〜Ｒ^２８は、それぞれ独立に、水素原子、ハロゲン原子、炭素数１〜１２のアルキル基、又は炭素数１〜１２のハロゲン化アルキル基を表し；そして、
式（２−１）〜（２−３）及び（２−５）中のｎは、それぞれ独立に、０〜３の整数である。} [Compound X and Compound Y]
The non-aqueous electrolytic solution comprises a compound X represented by the following chemical formula (1) and at least one compound Y selected from compounds represented by the following chemical formulas (2-1) to (2-5): Is preferred.

{In the formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a formyl group, an acyl group having 2 to 7 carbon atoms, a nitrile group, an alkyl group having 1 to 6 carbon atoms, 1 carbon atom It represents an alkoxy group of -6, an alkylcarbonyloxy group having 2 to 7 carbon atoms, or an alkyloxycarbonyl group having 2 to 7 carbon atoms. }

{Formula ^{(2-1) ~ (2-5) R} 5 ~R 28 in each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated having 1 to 12 carbon atoms Represents an alkyl group; and
N in formulas (2-1) to (2-3) and (2-5) is each independently an integer of 0 to 3. }

The compound X functions as a precursor of a compound having a C—S—C structure which gives a film expressing S2p spectrum and C1s spectrum in XPS of the surface of the positive electrode active material.
The acyl group having 2 to 7 carbon atoms of R ^{1 to} R ⁴ in the chemical formula (1) is typically an acetyl group. The C2-C7 alkylcarbonyloxy group represented by R ^{1 to} R ⁴ is typically an acetyloxy group (CH ₃ C (= O) O—). The alkyloxycarbonyl group having 2 to 7 carbon atoms of R ^{1 to} R ⁴ is typically a methoxycarbonyl group (CH ₃ —O—C (−O) —).
As the compound X, specifically, for example, thiophene, 2-methylthiophene, 3-methylthiophene, 2-cyanothiophene, 3-cyanothiophene, 2,5-dimethylthiophene, 2-methoxythiophene, 3-methoxythiophene, 2-chlorothiophene, 3-chlorothiophene, 2-acetylthiophene, 3-acetylthiophene and the like can be mentioned, and it is preferable to include one or more selected from these in the non-aqueous electrolytic solution in the present embodiment. .
0.01 mass% or more and 4.5 mass% or less are preferable with respect to the total mass of non-aqueous electrolyte solution, and, as for the content rate of the compound X in a non-aqueous electrolyte solution, 0.05 mass% or more and 4.0 mass% The following are more preferable, and 0.1 mass% or more and 3.5 mass% or less are still more preferable.

On the other hand, the compound Y functions as a precursor of a sulfur-containing compound which gives a film expressing an S2p spectrum in XPS of the surface of the negative electrode active material.
As a C1-C12 alkyl group in R < ⁵ > -R < ²⁸ > in Formula (2-1)-(2-5), a C1-C6 alkyl group is preferable, For example, a methyl group, an ethyl group, And propyl, butyl, pentyl, hexyl and the like. The halogenated alkyl group having 1 to 12 carbon atoms is preferably a halogenated alkyl group having 1 to 6 carbon atoms. For example, chloromethyl group, dichloroethyl group, 3,3,3-trifluoropropyl group, perfluoropropyl group It is fundamental.
Specifically as compound X,
Examples of the compound represented by the chemical formula (2-1) include ethylene sulfate, 1,3-propylene sulfate and the like;
Examples of the compound represented by the chemical formula (2-2) include 1,3-propane sultone, 2,4-butane sultone, 1,4-butane sultone, 1,3-butane sultone, 2,4-pentane sultone and the like;
Examples of the compound represented by the chemical formula (2-3) include 1,3-propene sultone, 1,4-butene sultone and the like;
Examples of the compound represented by the chemical formula (2-4) include 3-sulfolen and the like;
Examples of the compound represented by the chemical formula (2-5) include ethylene sulfite, 1,2-propylene sulfite propylene, 1,3-propylene sulfite propylene and the like;
Each of them can be mentioned, and one or more selected from these are preferably contained in the non-aqueous electrolytic solution of the present embodiment.
The content ratio of the compound Y in the non-aqueous electrolyte solution is 0 as the ratio of the total mass of the compounds represented by each of the chemical formulas (2-1) to (2-5) to the total mass of the non-aqueous electrolyte solution. .01 mass% or more and 4.5 mass% or less are preferable, 0.05 mass% or more and 4.0 mass% or less are more preferable, and 0.1 mass% or more and 3.5 mass% or less are further preferable.

[Non-aqueous solvent]
The non-aqueous electrolytic solution in the present embodiment preferably contains, as a non-aqueous solvent, at least one selected from cyclic carbonates and linear carbonates.
It is advantageous that the non-aqueous electrolyte contains a cyclic carbonate in that it dissolves a lithium salt of a desired concentration. Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate, butylene carbonate, vinylene carbonate, fluoroethylene carbonate (FEC), difluoroethylene carbonate (dFEC) and the like.
The total content of the cyclic carbonate is preferably 15% by mass or more, more preferably 20% by mass or more, based on the total amount of the non-aqueous electrolyte solution. If the said total content is 15 mass% or more, it will become possible to dissolve a lithium salt of a desired density | concentration, and high lithium ion conductivity can be expressed. The total content of cyclic carbonates is preferably 70% by mass or less, or 65% by mass or less, based on the total amount of the non-aqueous electrolyte solution.

Further, it is advantageous that the non-aqueous electrolytic solution in the present embodiment contains a linear carbonate in that high lithium ion conductivity is exhibited. Examples of chain carbonates include dialkyl carbonate compounds represented by dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, dipropyl carbonate, dibutyl carbonate and the like. The dialkyl carbonate compounds are typically unsubstituted.
The total content of the linear carbonate is preferably 30% by mass or more, more preferably 35% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, based on the total amount of the non-aqueous electrolyte is there. When the content of the linear carbonate is 30% by mass or more, the viscosity of the electrolytic solution can be reduced, and high lithium ion conductivity can be exhibited. When the total concentration is 95% by mass or less, the electrolytic solution can easily further contain an additive described later.

The nonaqueous electrolytic solution in the present embodiment contains at least one selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and fluoroethylene carbonate as a nonaqueous solvent. It is preferable to
It contains at least one linear carbonate selected from dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate, and at least one cyclic carbonate selected from ethylene carbonate, propylene carbonate, butylene carbonate, and fluoroethylene carbonate It is more preferable to do.

[Additive]
The non-aqueous electrolytic solution in the present embodiment is not only the above compound X and compound Y, and the non-aqueous solvent, but also from cyclic phosphazene, non-cyclic fluorine-containing ether, cyclic carbonate, cyclic carboxylic acid ester, cyclic acid anhydride and the like. It may contain one or more selected.

(Cyclic phosphazene)
Examples of the cyclic phosphazene include ethoxypentafluorocyclotriphosphazene, diethoxytetrafluorocyclotriphosphazene, phenoxypentafluorocyclotriphosphazene and the like, and one or more selected from these are preferable.

  The content of the cyclic phosphazene in the non-aqueous electrolyte solution is preferably 0.5% by mass or more and 20% by mass or less based on the total amount of the non-aqueous electrolyte solution. If this value is 0.5% by weight or more, it is possible to suppress the decomposition of the electrolytic solution at high temperature and suppress the gas generation. On the other hand, if this value is 20% by mass or less, the decrease in the ion conductivity of the electrolytic solution can be suppressed, and high input / output characteristics can be maintained. The content of cyclic phosphazene is more preferably 2% by mass to 15% by mass, and still more preferably 4% by mass to 12% by mass.

(Non-cyclic fluorine-containing ether)
As the non-cyclic fluorinated ether, for example, HCF ₂ CF ₂ OCH ₂ CF ₂ CF ₂ H, CF ₃ CFHCF ₂ OCH ₂ CF ₂ CF ₂ H, HCF ₂ CF ₂ CH ₂ OCH ₂ CF ₂ CF ₂ H, CF ₃ CFHCF ₂ OCH ₂ CF ₂ CFHCF _{3 and the} like can be mentioned, and one or more selected from these can be used. Among them, HCF ₂ CF ₂ OCH ₂ CF ₂ CF ₂ H is preferable from the viewpoint of electrochemical stability.

  The content of the non-cyclic fluorinated ether in the non-aqueous electrolytic solution is preferably 0.5% by mass or more and 15% by mass or less based on the total amount of the non-aqueous electrolytic solution, and is 1% by mass or more and 10% by mass or less Is more preferred. When the content of the non-cyclic fluorine-containing ether is 0.5% by mass or more, the stability of the non-aqueous electrolyte solution against oxidative decomposition is enhanced, and a storage element having high durability at high temperature can be obtained. On the other hand, if the content of the non-cyclic fluorine-containing ether is 15% by mass or less, the solubility of the electrolyte salt can be well maintained, and the ion conductivity of the non-aqueous electrolyte can be maintained high. It becomes possible to express input / output characteristics.

(Cyclic carbonate)
For cyclic carbonates, vinylene carbonate is preferred.
The content of the cyclic carbonate is preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 5% by mass, based on the total amount of the non-aqueous electrolytic solution. When the content of the cyclic carbonate is 0.5% by mass or more, a good film on the negative electrode can be formed, and the durability at high temperature can be obtained by suppressing the reductive decomposition of the electrolytic solution on the negative electrode. A high storage element can be obtained. On the other hand, if the content of the cyclic carbonate is 10% by mass or less, the solubility of the lithium salt can be maintained well, and the ion conductivity of the non-aqueous electrolyte can be maintained high, so high input / output It becomes possible to express the characteristic.

(Cyclic carboxylic acid ester)
Examples of cyclic carboxylic acid esters include gamma-butyrolactone, gamma-valerolactone, gamma-caprolactone, epsilon-caprolactone and the like, and it is preferable to use one or more selected from these. Among them, gamma-butyrolactone is particularly preferable in view of the improvement of the battery characteristics derived from the improvement of the lithium ion dissociation degree.
The content of the cyclic carboxylic acid ester is preferably 0.5% by mass to 15% by mass, and more preferably 1% by mass to 5% by mass, based on the total amount of the non-aqueous electrolyte solution. If the content of the cyclic acid anhydride is 0.5% by mass or more, a good film can be formed on the negative electrode, and by suppressing the reductive decomposition of the non-aqueous electrolytic solution on the negative electrode, at high temperature A highly durable storage element can be obtained. On the other hand, if the content of the cyclic carboxylic acid ester is 15% by mass or less, the solubility of the lithium salt can be well maintained, and the ion conductivity of the non-aqueous electrolyte can be maintained high. It becomes possible to express output characteristics.

(Cyclic acid anhydride)
The cyclic acid anhydride is preferably at least one selected from succinic anhydride, maleic anhydride, citraconic anhydride, and itaconic anhydride. Above all, it is preferable to select from succinic anhydride and maleic anhydride from the viewpoint that the production cost of the electrolyte can be suppressed by industrial availability and the point that it can be easily dissolved in non-aqueous electrolyte.
The content of the cyclic acid anhydride is preferably 0.5% by mass or more and 15% by mass or less, and more preferably 1% by mass or more and 10% by mass or less, based on the total amount of the non-aqueous electrolyte solution. If the content of the cyclic acid anhydride is 0.5% by mass or more, a good film can be formed on the negative electrode, and high temperature durability can be obtained by suppressing reductive decomposition of the electrolytic solution on the negative electrode. A high storage element can be obtained. On the other hand, if the content of the cyclic acid anhydride is 15% by mass or less, the solubility of the electrolyte salt can be well maintained, and the ion conductivity of the non-aqueous electrolyte can be maintained high, thus high input / output It becomes possible to express the characteristic. The above cyclic acid anhydrides may be used alone or in combination of two or more.

<Exterior body>
As an exterior body in the non-aqueous lithium-type storage element of the present embodiment, for example, a metal can, a laminate packaging material, or the like can be used.
The metal can is preferably made of aluminum.
As a laminate packaging material, a film in which a metal foil and a resin film are laminated is preferable, and a three-layer structure composed of an outer layer resin film / metal foil / interior resin film is exemplified. The outer layer resin film is for preventing the metal foil from being damaged by contact or the like, and a resin such as nylon or polyester can be suitably used. The metal foil is for preventing permeation of moisture and gas, and foils of copper, aluminum, stainless steel and the like can be suitably used. Further, the inner resin film protects the metal foil from the non-aqueous electrolytic solution housed inside, and is for melting and sealing at the time of heat sealing of the outer package, and polyolefin, acid-modified polyolefin and the like can be suitably used.

<Non-aqueous lithium type storage element>
The non-aqueous lithium-type storage element of the present embodiment is configured such that the negative electrode, the positive electrode, the separator, and the non-aqueous electrolytic solution are accommodated in the outer layer body. Preferably, the negative electrode, the positive electrode, and the separator are configured by housing an electrode laminate or an electrode wound body described later, together with the above-described non-aqueous electrolyte solution, in an exterior body described later.

<Method of manufacturing non-aqueous lithium type storage element>
[Fabrication of electrode assembly]
The electrode body in the present specification is a concept including an electrode laminate and an electrode winding body, and includes at least one structure in which a positive electrode precursor, a separator, and a negative electrode are laminated in this order.
An electrode laminated body connects a positive electrode terminal and a negative electrode terminal to the laminated body formed by laminating | stacking the positive electrode precursor and negative electrode which were cut in the shape of a single leaf through a separator. An electrode winding body connects a positive electrode terminal and a negative electrode terminal to the winding body which laminated | stacked and wound the positive electrode precursor and the negative electrode through the separator. The shape of the electrode winding body may be cylindrical or flat.
The method of connection of the positive electrode terminal and the negative electrode terminal is not particularly limited, but may be performed by a method such as resistance welding or ultrasonic welding.

  The non-aqueous lithium-type storage element in this embodiment typically includes the following steps of housing in an outer package, optionally performed drying step, liquid injection / impregnation / sealing step, lithium doping step, and aging step Can be manufactured by performing sequentially. After the aging step, an additional charging step or a degassing step, or both of them may be further performed.

[Storing process to the exterior body]
The electrode body is dried if necessary, and then housed in an outer package such as a metal can or a laminate packaging material, and only one opening for injecting the non-aqueous electrolyte is left. It is preferable to seal with. Although the sealing method of an exterior body is not specifically limited, When using a lamination wrapping material, methods, such as a heat seal and an impulse seal, can be used.

[Drying process]
It is preferable to remove the remaining solvent by further drying the electrode body housed in the outer package. Although the method of drying is not limited, for example, it may be dried by vacuum drying or the like. The residual solvent is preferably 1.5% by mass or less based on the mass of the positive electrode active material layer or the negative electrode active material layer. If the residual solvent content is more than 1.5% by mass, the deterioration of the self-discharge characteristics or the cycle characteristics due to the solvent remaining in the system is not preferable.

[Injection, impregnation, sealing process]
After completion of the housing step in the housing and the optional drying step, the non-aqueous electrolyte is poured into the housing containing the electrode body.
After pouring, it is desirable to further carry out impregnation, and sufficiently immerse the positive electrode, the negative electrode, and the separator with the non-aqueous electrolytic solution. In a state where at least a part of the positive electrode, the negative electrode, and the separator is not immersed in the non-aqueous electrolyte solution, in the lithium doping step described later, the doping proceeds nonuniformly, so the resistance of the obtained non-aqueous lithium storage element is obtained. Problems such as rising and decreasing in durability may occur. The method of impregnation is not particularly limited. For example, the electrode body after liquid injection is placed in a vacuum chamber with the exterior body open, and the inside of the chamber is decompressed using a vacuum pump, and atmospheric pressure is again applied. It is possible to use a method of returning to.
After liquid injection, preferably after impregnation, the outer package can be sealed by sealing while depressurizing the electrode assembly in a state where the outer package is open.

[Lithium doping process]
In the lithium doping step, a voltage is applied between the positive electrode precursor and the negative electrode to decompose an alkali metal compound in the positive electrode precursor to release lithium ions, and lithium ions are reduced at the negative electrode to obtain a negative electrode. Lithium ions are pre-doped into the active material layer.
In this lithium doping step, gas such as CO ₂ is generated along with the decomposition of the alkali metal compound in the positive electrode precursor. Therefore, when applying a voltage, it is preferable to take means for releasing the generated gas to the outside of the package. As this means, for example, a method of applying a voltage in a state in which a part of the exterior body is opened; in a state in which an appropriate gas discharge means such as a degassing valve, a gas permeable film, etc. Method of applying voltage; etc. can be mentioned.
Through the lithium ion process, the “positive electrode precursor” in the storage element becomes a “positive electrode”.

[Aging process]
It is preferable to perform an aging step after the lithium doping step. In the aging step, the solvent in the non-aqueous electrolytic solution is decomposed at the negative electrode, and a lithium ion permeable solid polymer film is formed on the surface of the negative electrode. This solid polymer film is considered to function as SEI (Solid Electrolyte Interphase).
The method of aging is not particularly limited, and for example, a method of reacting a solvent in the non-aqueous electrolytic solution in a high temperature environment can be used.

[Additional charging process]
After aging, it is preferable to additionally charge the electrode body. The additional charge causes the electrolyte in the non-aqueous electrolyte to be decomposed at the positive electrode. As a result, fluoride ions are released and attached to the separator surface to produce particulate matter. As a result, the permeability and retention of the electrolyte solution to the separator is improved, so that a low-resistance non-aqueous lithium-type storage element can be obtained. In addition, the adhesion of particulate matter to the surface of the separator increases the mechanical and electrochemical durability of the separator at high temperatures, and as a result, a non-aqueous lithium storage element having excellent durability at high temperatures. You can get

[Gas removal process]
Furthermore, it is preferable to perform a degassing step to reliably remove the gas remaining in the non-aqueous electrolyte solution, the positive electrode, and the negative electrode. In the state where the gas remains in at least a part of the non-aqueous electrolytic solution, the positive electrode, and the negative electrode, the ion conduction is inhibited, and the resistance of the obtained non-aqueous lithium-type storage element is increased.
The method of degassing is not particularly limited, but for example, a method of placing the electrode body in a reduced pressure chamber in a state where the outer package is opened, and reducing the pressure in the chamber using a vacuum pump can be used.

<Characteristics of non-aqueous lithium type storage element>
The non-aqueous lithium-type storage element of the present embodiment has low internal resistance both at normal temperature and high temperature, has a high capacity retention rate when charge and discharge cycles are repeated, and lithium precipitation is suppressed. Furthermore, the amount of generated gas when stored for a long time in a high temperature environment in a highly charged state is small, and the rate of increase in internal resistance is suppressed.

The non-aqueous lithium type storage element of the present embodiment has an initial room temperature internal resistance Ra (Ω), a capacitance F (F), an electric energy E (Wh), and an electrode body Assuming that the volume of the housed outer package is V (L) and the internal resistance at an ambient temperature of −10 ° C. is Rb, the following requirements (a), (b), and (c):
(A) The product Ra · F of Ra and F is 0.3 or more and 3.0 or less,
(B) E / V is 15 or more and 50 or less, and (c) Rb / Ra is 10 or less,
Can be satisfied at the same time.

  Regarding the requirement (a), Ra · F is preferably 3.0 or less, more preferably 2.6 or less, from the viewpoint of expressing sufficient charge capacity and discharge capacity with respect to a large current. More preferably, it is 2.4 or less. If Ra · F is less than or equal to the above upper limit value, a non-aqueous lithium-type storage element having excellent input / output characteristics can be obtained. Therefore, by combining a storage system using a non-aqueous lithium type storage element with, for example, a high efficiency engine, it is possible to sufficiently withstand high load applied to the non-aqueous lithium type storage element.

  Regarding the requirement (b), E / V is preferably 15 or more, more preferably 18 or more, and still more preferably 20 or more from the viewpoint of achieving sufficient charge capacity and discharge capacity. If E / V is more than said lower limit, the electrical storage element which has the outstanding volume energy density can be obtained. Therefore, when using a storage system using a storage element in combination with, for example, an engine of a car, it is possible to install the storage system in a limited narrow space in the car.

  With respect to requirement (c), Rb / Ra is preferably 10 or less, more preferably 8 or less, from the viewpoint of exhibiting sufficient charge capacity and discharge capacity even in a low temperature environment of −10 ° C. More preferably, it is 6 or less. If Rb / Ra is less than or equal to the above upper limit value, a storage element having excellent output characteristics even in a low temperature environment can be obtained. Therefore, it is possible to obtain a storage element that provides sufficient power to drive a motor when starting an engine such as a car or a motorcycle under a low temperature environment.

The non-aqueous lithium-type storage element of this embodiment has an initial room temperature internal resistance at a cell voltage of 4.2 V stored in Ra (Ω), a cell voltage of 4.2 V and an environmental temperature of 60 ° C. for two months at 25 ° C. Assuming that the internal resistance at R c (Ω), the following requirements (d) and (e):
(D) Rc / Ra is 0.3 or more and 3.0 or less, and (e) the amount of gas generated when stored for 2 months at a cell voltage of 4.2 V and an environmental temperature of 60 ° C. is 60 × at 25 ° C. Less than 10 ^-3 cc / F,
Can be satisfied at the same time.

  Regarding requirement (d), Rc / Ra is 3.0 or less from the viewpoint of exhibiting sufficient charge capacity and discharge capacity for large current when exposed to a high temperature environment for a long time Preferably it is 2.0 or less, More preferably, it is 1.5 or less. If Rc / Ra is less than or equal to the above upper limit value, excellent output characteristics can be obtained stably for a long time, leading to a long life of the device.

Regarding requirement (e), the amount of gas generated when stored for two months at a cell voltage of 4.2 V and an environmental temperature of 60 ° C. does not degrade the characteristics of the device by the generated gas, the amount of generated gas is 25 ° C. It is preferable that it is 60 * 10 < ^-3 > cc / F or less as a value measured in, More preferably, it is 45 * 10 < ^-3 > cc / F or less, More preferably, it is 30 * 10 < ^-3 > cc / F or less . If the amount of gas generated under the above conditions is equal to or less than the above upper limit value, there is no risk that the cell will expand due to gas generation even if the device is exposed to high temperature for a long time. Therefore, a storage element having sufficient safety and durability can be obtained.

  The parameters Ra · F, E / V, Rb / Ra, Rc / Ra, and the amount of generated gas described above are values measured and calculated by the method described in the examples described later.

<Applications of non-aqueous lithium type storage element>
A plurality of non-aqueous lithium-type storage devices according to the present embodiment can produce a storage module by connecting them in series or in parallel.
The non-aqueous lithium storage element and storage module of this embodiment have high output and high capacity, and can maintain their characteristics over a wide range of environmental temperatures. For example, a power regeneration system, a power load leveling system, no It can be applied to blackout power supply systems, non-contact power supply systems, energy harvesting systems, storage systems and the like. In particular, applications requiring high load charge / discharge cycle characteristics, for example, power regeneration systems for hybrid drive systems for automobiles; natural power generation such as solar power generation or wind power generation; power load leveling systems for micro grids; Uninterruptible power supply system in etc .; Non-contact power supply system for equalization of voltage fluctuation such as microwave power transmission or electric field resonance and storage of energy; Energy harvest system for utilization of electric power generated by vibration power generation etc .; Etc., can be suitably applied.

  Hereinafter, the present invention will be specifically described by way of Examples and Comparative Examples, but the present invention is not limited thereto.

<Manufacture of positive electrode precursor>
(1) Pulverization of lithium carbonate 200 g of lithium carbonate having an average particle diameter of 53 μm is cooled to -196 ° C with liquid nitrogen using a grinder made by Imex (liquid nitrogen bead mill LNM), and then dry ice beads are used, It ground for 9 minutes by 10.0 m / s of circumferential speeds.
According to the above-described operation, lithium carbonate was crushed by brittle fracture while preventing heat denaturation at -196 ° C.
It was 1.5 micrometers when the average particle diameter was measured about lithium carbonate after this grinding | pulverization.

(2) Preparation of Cathode Active Material (2-1) Preparation of Cathode Active Material (Activated Carbon A) The crushed coconut husk carbide is carbonized at 500 ° C. for 3 hours in a small carbonization furnace under a nitrogen atmosphere to obtain a carbide. The The obtained carbide was put into an activation furnace, and 1 kg / h of steam was introduced into the activation furnace in a heated state with a preheating furnace, heated to 900 ° C. in 8 hours, and activated. The activated carbide was taken out and cooled in a nitrogen atmosphere to obtain activated activated carbon. The obtained activated carbon was washed with water for 10 hours and then drained. Then, after drying for 10 hours in the electric dryer kept at 115 ° C., pulverization was carried out with a ball mill for 1 hour to obtain activated carbon A as a positive electrode active material.
About this activated carbon A, it was 4.2 micrometers as a result of measuring an average particle diameter using Shimadzu Corp. make laser-diffraction-type particle size distribution analyzer (SALD-2000J). Moreover, pore distribution was measured using the pore distribution measuring apparatus (AUTOSORB-1 AS-1-MP) made by Yuasa Ionics. As a result, the BET specific surface area was 2,360 m ² / g, the amount of mesopores (V1) was 0.52 cc / g, the amount of micropores (V2) was 0.88 cc / g, and V1 / V2 = 0.59. .

(2-2) Preparation of Positive Electrode Active Material (Activated Carbon B) The phenol resin is carbonized for 2 hours at 600 ° C. in a baking furnace under a nitrogen atmosphere, then pulverized in a ball mill, and further classified. A carbide having an average particle diameter of 7 μm was obtained. The carbide and KOH were mixed at a mass ratio of 1: 5, and activation was performed by heating at 800 ° C. in a baking furnace for 1 hour in a nitrogen atmosphere. Thereafter, the mixture was stirred and washed in dilute hydrochloric acid adjusted to a concentration of 2 mol / L for 1 hour. Furthermore, the mixture was boiled and washed with distilled water until the pH was stabilized at 5 to 6 and then dried to obtain activated carbon B as a positive electrode active material.
The pore distribution of this activated carbon B was measured using a pore distribution measuring apparatus (AUTOSORB-1 AS-1-MP) manufactured by Yuasa Ionics. As a result, the BET specific surface area was 3,627 m ² / g, the amount of mesopores (V1) was 1.50 cc / g, the amount of micropores (V2) was 2.28 cc / g, and V1 / V2 = 0.66. .

<Manufacture of negative electrode>
(1) Production of Negative Electrode A (1-1) Preparation of Negative Electrode Active Material A 150 g of commercially available coconut shell activated carbon having an average particle diameter of 3.0 μm and a BET specific surface area of 1,780 m ² / g as a base material is stainless steel mesh Put in a wooden bowl and place it on a stainless steel vat containing 270g of coal-based pitch (softening point: 50 ° C), place both in an electric furnace (effective size 300mm × 300mm × 300mm in the furnace), By performing the reaction, a composite carbon material A was obtained. This heat treatment was performed under a nitrogen atmosphere, heated to 600 ° C. for 8 hours, and held at the same temperature for 4 hours. Subsequently, the composite carbon material A was taken out of the furnace after being cooled to 60 ° C. by natural cooling.
The average particle size and the BET specific surface area of the obtained composite carbon material A were measured in the same manner as in the case of the activated carbon A. As a result, the average particle size was 3.2 μm, and the BET specific surface area was 262 m ² / g.
In the composite carbon material A, the mass ratio of the carbonaceous material derived from the coal-based pitch to the activated carbon was 78%.

(1-2) Production of Negative Electrode A Subsequently, using the composite carbon material A obtained above as a negative electrode active material, a negative electrode A was produced.
A mixed liquid was obtained by mixing 85 parts by mass of the composite carbon material A, 10 parts by mass of acetylene black, and 5 parts by mass of PVdF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone). The obtained mixed solution was dispersed at a peripheral speed of 15 m / s using a thin film swirl type high speed mixer film mix manufactured by PRIMIX, to obtain a coating solution.
The viscosity (η b) and the TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,789 mPa · s, and the TI value was 4.3.
The above coating solution is coated on both sides of a 10 μm thick electrolytic copper foil having no through holes at a coating speed of 1 m / s using a die coater manufactured by Toray Engineering Co., Ltd. at a drying temperature of 85 ° C. After drying, pressing was performed using a roll press under a condition of a pressure of 4 kN / cm and a surface temperature of 25 ° C. of a pressing portion, to obtain a negative electrode A (double-sided negative electrode A).
The thickness of the obtained negative electrode active material layer of the negative electrode A was measured using a thickness gauge Linear Gauge Sensor GS-551 manufactured by Ono Keiki Co., Ltd. Specifically, the thickness of the negative electrode A is measured at any ten places of the negative electrode A, and the value obtained by subtracting the thickness of the copper foil from the average value of the obtained thicknesses is the thickness of the negative electrode active material layer Asked as. As a result, the thickness of the negative electrode active material layer of the negative electrode A was 40 μm per side.

(2) Production of Negative Electrode B (2-1) Preparation of Negative Electrode Active Material B Using artificial graphite having an average particle diameter of 4.9 μm as a substrate instead of the composite carbon material A, the amount of coal pitch used is 50 g, Furthermore, a composite carbon material B was manufactured and evaluated in the same manner as in the preparation of the negative electrode active material A, except that the heat treatment temperature was 1,000 ° C. As a result, the BET specific surface area of the composite carbon material B was 6.1 m ² / g.
In the composite carbon material B, the mass ratio of the carbonaceous material derived from the coal-based pitch to the artificial graphite was 2%.

(2-2) Production of Negative Electrode B The negative electrode B was produced using the composite carbon material B obtained above as a negative electrode active material.
80 parts by mass of composite carbon material B, 8 parts by mass of acetylene black, 12 parts by mass of PVdF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone) were mixed to obtain a liquid mixture. The obtained mixed liquid was dispersed at a peripheral speed of 15 m / s using a thin film swirl type high speed mixer film mix manufactured by PRIMIX, to obtain a coating liquid.
The viscosity (η b) and the TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,798 mPa · s, and the TI value was 2.7.
The above coating solution is coated on both sides of a 10 μm thick electrolytic copper foil having no through holes at a coating speed of 1 m / s using a die coater manufactured by Toray Engineering Co., Ltd. at a drying temperature of 85 ° C. After drying, pressing was performed using a roll press under a condition of a pressure of 4 kN / cm and a surface temperature of 25 ° C. of a pressing part to obtain a negative electrode B (double-sided negative electrode B).
Moreover, the thickness of the negative electrode active material layer of the negative electrode B measured by the method similar to the negative electrode A was 25 micrometers per single side | surface.

(3) Production of Negative Electrode C A negative electrode was manufactured in the same manner as in the production of negative electrode A, except that in the above “(1) Production of negative electrode A”, a 15 μm thick copper foil with through holes was used as the negative electrode current collector. C (double-sided negative electrode C) was manufactured.
The thickness of the negative electrode active material layer of the negative electrode C was 40 μm per side.

(4) Production of Negative Electrode D The negative electrode was produced in the same manner as in the production of the negative electrode B except that in the above “(2) Production of the negative electrode B”, a copper foil having a thickness of 15 μm and having through holes was used. D (double-sided negative electrode D) was produced.
The thickness of the negative electrode active material layer of the negative electrode D was 25 μm per side.

Example 1
(1) Production of Positive Electrode Precursor Using the activated carbon A obtained in the above (2-1) as a positive electrode active material and using the lithium carbonate after pulverization obtained in the above (1) as an alkali metal compound, a positive electrode precursor Manufactured.
57.5 parts by mass of activated carbon A, 30.0 parts by mass of lithium carbonate having an average particle diameter of 1.5 μm as an alkali metal compound, 3.0 parts by mass of KB (Ketjen black), PVP (polyvinylpyrrolidone) A mixed solution was obtained by mixing 5 parts by mass, 8.0 parts by mass of PVDF (polyvinylidene fluoride), and NMP (N-methylpyrrolidone). The obtained mixed liquid was dispersed at a peripheral speed of 17 m / s using a thin film swirl type high speed mixer film mix manufactured by PRIMIX, to obtain a coating liquid.
The viscosity (η b) and the TI value of the obtained coating liquid were measured using an E-type viscometer TVE-35H manufactured by Toki Sangyo Co., Ltd. As a result, the viscosity (ηb) was 2,700 mPa · s, and the TI value was 3.5. Further, the degree of dispersion of the obtained coating liquid was measured using a particle gauge manufactured by Yoshimitsu Seiki. As a result, the particle size was 35 μm.
The above coating solution is coated on one side or both sides of a 15 μm thick aluminum foil as a positive electrode current collector at a coating speed of 1 m / s using a die coater manufactured by Toray Engineering Co., Ltd., at a drying temperature After drying at 100 ° C., pressing was performed using a roll press under a pressure of 4 kN / cm and a surface temperature of 25 ° C. of the pressing portion, to obtain a positive electrode precursor.
The film thickness of the positive electrode active material layer of the obtained positive electrode precursor was measured using a thickness gauge Linear Gauge Sensor GS-551 manufactured by Ono Keiki Co., Ltd. Specifically, the thickness of the positive electrode precursor is measured at any 10 places of the positive electrode precursor, and the value obtained by subtracting the thickness of the aluminum foil from the average value of the obtained thicknesses is a positive electrode active material layer The thickness of the As a result, the thickness of the positive electrode active material layer of the positive electrode precursor was 60 μm per side.

(2) Preparation of Electrolytic Solution A mixed solvent of ethylene carbonate (EC): dimethyl carbonate (DMC): methyl ethyl carbonate (EMC) = 33.0: 44.0: 23.0 (volume ratio) as an organic solvent is used. And the concentration ratio of LiN (SO ₂ F) ₂ and LiPF _{6 to} the whole electrolyte solution is 50: 50 (molar ratio), and the sum of the concentration of LiN (SO ₂ F) ₂ and LiPF ₆ is 1.2 mol / In a solution obtained by dissolving each electrolyte salt so as to be L, 0.1% by mass of thiophene as Compound X of the additives and 0.1% by mass of 1,3-propanesultone as Compound Y in the additive The non-aqueous electrolyte solution was prepared by adding.
The concentrations of LiN (SO ₂ F) ₂ and LiPF ₆ in the electrolyte prepared here were 0.6 mol / L and 0.6 mol / L, respectively.

(3) Assembly of Storage Element The double-sided negative electrode A, the single-sided positive electrode precursor and the double-sided positive electrode precursor were cut into 10 cm × 10 cm (100 cm ² ), respectively. A microporous film with a thickness of 15 μm is used between the negative electrode A and the positive electrode precursor, using the single-sided positive electrode precursor on the top and bottom surfaces and using 21 double-sided negative electrodes A2 and 20 double-sided positive electrode precursors. It laminated | stacked on both sides of the separator. Thereafter, the negative electrode terminal and the positive electrode terminal were connected to the negative electrode A and the positive electrode precursor A by ultrasonic welding, respectively, to obtain an electrode laminate. The electrode laminate was vacuum dried at 80 ° C. and 50 Pa for 60 hours. The electrode laminate is housed in an exterior body made of an aluminum laminate packaging material in a dry air environment with a dew point of −45 ° C., and then the exterior body is heat sealed leaving a non-aqueous electrolyte solution injection port. The element was assembled. The heat sealing was performed under conditions of 180 ° C., 20 sec, and 1.0 MPa.

(4) Production of non-aqueous lithium-type storage element (injection of non-aqueous electrolyte solution, impregnation, and sealing process)
The electrode laminate housed in the aluminum laminate packaging material as described above is placed in a dry air environment with a dew point of −40 ° C. or less, and about 80 g of the non-aqueous electrolyte prepared above is atmospheric pressure at a temperature of 25 ° C. Infused below. Subsequently, the electrode laminate after injection of the non-aqueous electrolyte solution was placed in a pressure reduction chamber, and after reducing the pressure from atmospheric pressure to −87 kPa, the pressure was returned to atmospheric pressure and allowed to stand for 5 minutes. Then, after depressurizing from normal pressure to -87 kPa, after repeating the 1st pressure-reduction process returned to atmospheric pressure 4 times, it left still for 15 minutes. Further, the pressure was reduced from normal pressure to -91 kPa, and then returned to atmospheric pressure. Similarly, the second depressurization step of depressurizing and returning to the atmospheric pressure was repeated a total of seven times. The degree of pressure reduction in the second pressure reduction step was -95, 96, 97, 81, 97, 97, and 97 kPa, respectively.
The non-aqueous electrolytic solution was impregnated into the electrode laminate through the above steps.
Thereafter, the non-aqueous lithium type storage element is put in a vacuum sealing machine, and the non-aqueous electrolyte solution inlet is heat sealed at 180 ° C. for 10 seconds at a pressure of 0.1 MPa in a state of reduced pressure The non-aqueous lithium type storage element was manufactured by sealing the material.

(5) Lithium Doping Step With respect to the obtained non-aqueous lithium-type storage element, using a charge / discharge device (TOSCAT-3100U) manufactured by Toyo System Co., Ltd., a voltage of 4. A at a current value of 0.2 A under 25 ° C. environment. After performing constant current charging until reaching 5 V, lithium doping was performed on the negative electrode by performing initial charging according to a method of continuing 4.5 V constant voltage charging for 30 hours.

(6) Aging step The non-aqueous lithium-type storage element after lithium doping is subjected to constant current discharge in a 45 ° C. environment to reach a voltage of 3.0 V at 0.7 A, and then a constant current of 1 A to 4.0 V It charged and adjusted voltage to 4.0V. Subsequently, aging was performed by storing the non-aqueous lithium-type storage element after voltage adjustment in a thermostat at 60 ° C. for 48 hours.

(7) Degassing Step The non-aqueous lithium type storage element after aging was placed in a dry air environment with a temperature of 25 ° C. and a dew point of −40 ° C., and a part of the aluminum laminate packaging material as an exterior body was unsealed. Subsequently, a non-aqueous lithium-type storage element in which a part of the outer package is opened is put in the decompression chamber, and a diaphragm pump (N816.3 KT. 45.18) manufactured by KNF Corporation is used. After reducing the pressure over 3 minutes, the process of returning to atmospheric pressure over 3 minutes was repeated a total of three times. Thereafter, a non-aqueous lithium storage element is placed in a vacuum sealing machine, and after decompressing to -90 kPa, the opening port is heat sealed at a pressure of 0.1 MPa for 10 seconds at 200 ° C. to seal the aluminum laminate packaging material. Gas was vented.

(8) Identification of Additives in Electrolyte Solution After adjusting the completed non-aqueous lithium type storage element to 2.9 V, the dew point is -90 ° C. or less installed in a room at 23 ° C., and the oxygen concentration is controlled to 1 ppm or less The electrolyte was collected using a syringe in an Ar box, placed in a polypropylene vial and sealed. The electrolyte in the vial was collected with a microsyringe while maintaining the non-air exposure, and GC / MS measurement was performed.
GC / MS measurements were performed using an Agilent Technology MSD5975. The measurement conditions were as follows.
GC inlet temperature: 300 ° C
Carrier gas: He
Flow rate: 1 mL / min
Column: Agilent Technologies, non-polar column DB-1 (30 m × 0.25 mm ID, film thickness 0.25 μm)
Column temperature: Temperature increase from 40 ° C to 300 ° C at 20 ° C / min:
Split ratio: 1/100
Injection volume: 1 μL
Interface temperature with MS: 300 ° C
MS source temperature: 230 ° C
Ionization Method: Electron Ionization Method As a result of the above-described method, thiophene and 1,3-propane sultone were detected in the electrolytic solution.

(9) Evaluation of non-aqueous lithium storage element (9-1) XPS on the surface of positive electrode active material layer
A non-aqueous lithium storage element completed by lithium doping and degassing is adjusted to a voltage of 2.9 V and then managed with a dew point of -90 ° C. or less and an oxygen concentration of 1 ppm or less installed in a room at 23 ° C. It disassembled in Ar box and took out the positive electrode. The taken out positive electrode was dipped and washed with dimethyl carbonate (DMC), and then vacuum dried in a side box under non-exposed to air.
The dried positive electrode was placed in a transfer vessel, and XPS measurement was performed while maintaining the non-air exposure.
The measurement conditions were as follows.
X-ray source: monochromized AlKα
X-ray beam diameter: 100 μmφ (25 W, 15 kV)
Pass energy (narrow scan): 58.70 eV
Charge neutralization: Yes Sweep number (narrow scan): 10 times (carbon, oxygen), 20 times (fluorine), 30 times (phosphorus), 40 times (lithium), or 50 times (silicon)
Energy step (narrow scan): 0.25 eV

In addition, before the measurement of XPS, the surface of the positive electrode was cleaned by sputtering. The conditions of sputtering were as follows.
Acceleration voltage: 1.0kV
Sputtering range: 2 mm × 2 mm
Sputtering time: 1 minute (1. 25 nm / min in terms of SiO ₂ )

Based on the area of each peak and the sensitivity coefficient of each element, the obtained XPS spectrum is assigned to each binding energy of Li1s, C1s, O1s, F1s, P2p, Si2p, and S2p according to the above criteria. Element concentration ratio S _{164 eV} when the element concentration determined based on the peak area of ₁₆₄ eV in the spectrum is S _{164 eV} (atomic%) and the element concentration determined based on the peak area of C in the C _1s spectrum is C (atomic%) / C was calculated.
As a result, the S _{164 eV} of the positive electrode of the non-aqueous lithium-type storage element of Example 1 was 0.05 atomic%, the element concentration C of C was 46 atomic%, and the ratio S _{164 eV} / C was 0.0011.

(9-2) Positive electrode active material layer BET specific surface area per unit area of positive electrode current collector A positive electrode taken out from the completed non-aqueous lithium-type storage element in the same manner as XPS of (9-1) positive electrode active material layer surface, After vacuum drying overnight at 200 ° C., adsorption and desorption isotherms were measured using nitrogen as an adsorbate. The positive electrode active material layer BET specific surface area per unit area of the positive electrode current collector (described as “BET per unit area” in Table 2) calculated using the obtained adsorption-side isotherm is 9.13 m ² / cm It was ² .

(9-3) XPS on the surface of the negative electrode active material layer
Using the negative electrode taken out from the completed nonaqueous lithium type storage element in the same manner as XPS of the surface of the positive electrode active material layer (9-1), using the same method as XPS of the surface of the positive electrode active material layer, The analysis was done.
As a result, S _{168 eV} of the negative electrode of the non-aqueous lithium-type storage element of Example 1 was 0.3 atomic%, F _{685 eV} was 11.5 atomic%, and the ratio S _{168 eV} / F _{685 eV} was 0.026.

(9-4) Evaluation of initial characteristics i) Calculation of volumetric energy density A charge / discharge device (5 V, 5 V, manufactured by Fujitsu Telecom Networks, Inc.) in a thermostatic chamber set at 25 ° C. for the completed non-aqueous lithium type storage element. Using 360 A), constant current charging was performed until reaching 4.2 V at a current value of 2 C, followed by constant voltage charging for applying a constant voltage of 4.2 V for a total of 30 minutes. Thereafter, the capacitance when performing constant current discharge at a current value of 2 C up to 2.2 V is represented by Q, and the capacitance F (F) calculated by F = Q / (4.2−2.2), Using the volume V (L), the following equation:
E / V = F × (4.2−2.2) / 2/3600 / V
It was 39.1 Wh / L when volume energy density was computed by this.
The symbol "E" in the above equation uses the capacitance F (F) to indicate the following equation:
E = F × (4.2 ² −2.2 ² ) / 2/3600
Is the amount of power calculated by

ii) Evaluation of initial time constant (calculation of Ra · F)
The completed non-aqueous lithium storage element reaches 4.2 V at a current value of 20 C using a charge / discharge device (5 V, 360 A) manufactured by Fujitsu Telecom Networks Ltd. in a thermostatic chamber set at 25 ° C. Until constant current charging, and then constant voltage charging for applying a constant voltage of 4.2 V for a total of 30 minutes, followed by constant current discharging at a current value of 20 C to 2.2 V, and a discharge curve (Time-Voltage) was obtained. In this discharge curve, the voltage at discharge time = 0 seconds obtained by extrapolation from the voltage values at discharge time of 2 seconds and 4 seconds is linear approximation, and E0 is the voltage drop ΔE = 4.2-Eo, and The normal temperature internal resistance Ra was calculated by R = ΔE / (20 C (current value A)).
In addition, the completed non-aqueous lithium type storage element is subjected to constant current charging until reaching 4.2 V at a current value of 20 C in a constant temperature bath set at 25 ° C., and then a constant voltage of 4.2 V is applied. Constant voltage charging for a total of 30 minutes. Thereafter, the capacitance F is calculated according to the formula: F = Q / (4.2−2.2), where Q is a capacity when constant current discharge is performed at a current value of 2 C up to 2.2 V.
The product Ra · F of the capacitance F obtained above and the normal temperature internal resistance Ra was 2.58 ΩF.

iii) Evaluation of low temperature characteristics (calculation of Rb / Ra)
The completed non-aqueous lithium type storage element was allowed to stand in a thermostat set at -10 ° C for 2 hours, and then the charge / discharge device (5 V made by Fujitsu Telecom Networks, Inc. while keeping the thermostat at -10 ° C , 360 A), constant current charging until reaching 4.2 V at a current value of 1.0 B, followed by constant voltage charging applying a constant voltage of 4.2 V for a total of 2 hours. Then, a constant current discharge was performed up to 2.2 V at a current value of 50 C to obtain a discharge curve (time-voltage). In this discharge curve, the voltage at discharge time = 0 seconds obtained by extrapolation from the voltage value at the time of discharge time 2 seconds and 4 seconds by linear approximation is Eo, and the following formula:
Drop voltage ΔE = 4.2−Eo, and Rb = ΔE / (10 C (current value A))
The low temperature internal resistance Rb was calculated by
And ratio Rb / Ra calculated | required from this low temperature internal resistance Rb and normal temperature internal resistance Ra calculated | required by said "ii) evaluation of initial time constant (calculation of Ra * F)" was 6.2.

(9-5) Evaluation of high temperature storage specification i) Evaluation of resistance increase rate ((calculation of Rc / Ra))
The completed non-aqueous lithium storage element achieves 4.2 V at a current value of 100 C using a charge / discharge device (5 V, 360 A) manufactured by Fujitsu Telecom Networks Ltd. in a thermostatic chamber set at 25 ° C. The constant current charge was performed until then, followed by a constant voltage charge applying a constant voltage of 4.2 V for a total of 10 minutes. Thereafter, the cell was stored at 60 ° C., removed from the environment at 60 ° C. every two weeks, charged to 4.2 V at the cell voltage in the same charging step, and then stored again at 60 ° C. . A two-month high-temperature storage test of the non-aqueous lithium-type storage element was performed by repeating this process for two months.
With respect to the storage element after the high temperature storage test, the internal temperature resistance Rc at normal temperature after the high temperature storage test by the same operation as the method of calculating Ra in the above “ii) Evaluation of initial time constant (calculation of Ra · F)”. Was calculated.
The ratio Rc / Ra calculated by dividing this Rc (Ω) by the normal temperature internal resistance Ra (Ω) before the high temperature storage test obtained in the above “ii) Evaluation of initial time constant (calculation of Ra · F)” , 1.75.

ii) Measurement of gas generation amount The cell volume Va before the start of the high temperature storage test and the volume Vb of the cell after the high temperature storage test for 2 months are respectively performed by the Archimedes method for the completed non-aqueous lithium type storage element It was measured.
The gas generation amount calculated | required by numerical formula: Vb-Va using these values was 59 * 10 < ^-3 > cc / F.

Examples 2 to 30 and Comparative Examples 1 to 10
According to the same method as “(1) Production of positive electrode precursor” in Example 1 except that the type of positive electrode active material is as described in Table 1, the thickness per one surface and both surfaces of the positive electrode current collector is used. A positive electrode precursor having a positive electrode active material layer of 60 μm was obtained.
Then, the types and addition amounts of the compound X and the compound Y, which are additives to be added to the negative electrode species and the non-aqueous electrolyte using the above positive electrode precursor, are changed as described in Table 1, respectively, A non-aqueous lithium storage element was manufactured in the same manner as in Example 1, and various evaluations were performed.
The evaluation results are shown in Table 2.

Examples 31 to 37 and Comparative Examples 11 to 14
The “(1) positive electrode of Example 1 was prepared except that the amount of activated carbon A used was 47.5 parts by mass, and the transition metal compound of the type and amount described in Table 1 was further used to prepare a coating liquid. According to the same method as “Production of Precursor”, a positive electrode precursor having a 60 μm-thick positive electrode active material layer per one surface was obtained on one side and both sides of a positive electrode current collector.
And, using the above-mentioned positive electrode precursor, the kind and the addition amount of the compound X and the compound Y, which are additives to be added to the non-aqueous electrolytic solution, are changed as described in Table 1, respectively. Similarly, a non-aqueous lithium type storage element was manufactured and various evaluations were performed.
The evaluation results are shown in Table 2.

Examples 38 to 41 and Comparative Examples 15 and 16
As shown in Table 3, storage inhibition was assembled in the same manner as in Example 1, and the non-aqueous electrolyte solution injection, impregnation, and sealing steps were sequentially performed to produce a non-aqueous lithium-type storage element.
With respect to the obtained non-aqueous lithium-type storage element, Table 4 shows the initial charging voltage in the “(5) lithium doping step” and the ultimate voltage of constant current charging in the “(6) aging step”. Lithium doping and aging, and various evaluations were performed in the same manner as in Example 1 except for the descriptions.
The evaluation results are shown in Table 4 together with the results of Example 1.

Comparative Example 17
(1) Production of Positive Electrode Precursor As shown in Table 3, the amount of activated carbon A used was 87.5 parts by mass, and the alkali metal compound was not used. According to the same method as “Production of Precursor”, a positive electrode precursor having a 60 μm-thick positive electrode active material layer per one surface was obtained on one side and both sides of a positive electrode current collector.
(2) Assembly of Storage Element The double-sided negative electrode C and the positive electrode precursor obtained above were cut into 10 cm × 10 cm (100 cm ² ), respectively. A lithium metal foil corresponding to 760 mAh / g per unit mass of the composite porous material A was attached to one side of the cut double-sided negative electrode C.
Between the negative electrode C and the positive electrode precursor, the single-sided positive electrode precursor is used for the top surface and the lowermost surface, and the double-sided negative electrode C21 with lithium foil stuck to one side and 20 double-sided positive electrode precursors. A microporous membrane separator with a thickness of 15 μm was stacked. A non-aqueous lithium-type storage element was assembled in the same manner as "(2) Assembly of a storage element" of Example 1 except that this laminate was used.
(3) Production of non-aqueous lithium-type storage element (injection of non-aqueous electrolyte solution, impregnation, and sealing process)
A non-aqueous lithium-type storage element was obtained by performing the injection, impregnation, and sealing steps of the non-aqueous electrolytic solution in the same manner as in Example 1.

(4) Lithium Doping Step Lithium doping was performed on the negative electrode by leaving the obtained non-aqueous lithium-type storage element for 21 hours in a thermostat set at 45 ° C.
(5) Aging Step The non-aqueous lithium-type storage element after lithium doping was adjusted to a cell voltage of 3.0 V and then stored for 24 hours in a thermostatic chamber set at 45 ° C. Subsequently, using a charge / discharge device manufactured by Aska Electronics, charge current 10 A, discharge current 10 A, constant current charge between lower limit voltage 2.0 V, upper limit voltage 4.0 V, charge / discharge cycle by constant current discharge 2 I repeated it several times.
(6) Evaluation of non-aqueous lithium-type storage element Various evaluations were performed in the same manner as in Example 1 except that the non-aqueous lithium-type storage element after the charge / discharge cycle was used.
The evaluation results are shown in Table 4 together with the results of Example 1.

<Comparative Examples 18 to 20>
A non-aqueous lithium type storage element was manufactured in the same manner as in Comparative Example 17 except that the type of the negative electrode and the type of the positive electrode active material used for manufacturing the positive electrode precursor were as shown in Table 3, respectively. The evaluation of
The evaluation results are shown in Table 4 together with the results of Example 1.

  The “BET per unit area” in the “positive electrode analysis result” in Table 4 is a positive electrode active material layer BET specific surface area per positive electrode current collector unit area.

The non-aqueous lithium-type storage element of the present invention can be suitably used, for example, as a storage element in an assist application of instantaneous power peak of a hybrid drive system of a car.
The non-aqueous lithium-type storage element of the present invention can be suitably applied as, for example, a lithium ion capacitor or a lithium ion secondary battery. The nonaqueous lithium-type storage element of the present invention is particularly preferable when applied as a lithium ion capacitor, because the effects of the present invention can be exhibited to the maximum.

Claims (25)

What is claimed is: 1. A non-aqueous lithium storage device comprising: a negative electrode, a positive electrode, a separator, and a non-aqueous electrolytic solution containing a lithium salt,
The negative electrode has a negative electrode current collector, and a negative electrode active material layer containing a negative electrode active material provided on one side or both sides of the negative electrode current collector, and the negative electrode active material contains lithium ions. Containing carbon material that can be occluded and released,
The elemental concentration of S determined based on the peak area of 168 eV in the S2p spectrum obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the negative electrode active material layer is S _{168 eV} (atomic%), peak area of 685 eV in the F1s spectrum The element concentration ratio S _{168 eV} / F _{685 eV} is 0.025 or more and 0.5 or less, where the element concentration of F determined on the basis of F is _{685 eV} (atomic%),
The positive electrode includes a positive electrode current collector and a positive electrode active material layer including a positive electrode active material provided on one side or both sides of the positive electrode current collector, and the positive electrode active material includes activated carbon. ,
Assuming that the specific surface area per unit area of the positive electrode active material layer measured by the BET method is A (m ² / cm ² ), 0.2 ≦ A ≦ 10, and
The elemental concentration of S determined based on the peak area of 164 eV in the S2p spectrum obtained by X-ray photoelectron spectroscopy (XPS) of the surface of the positive electrode active material layer is S _{164 eV} (atomic%) and the peak area of C in the C1s spectrum The nonaqueous lithium-type electrical storage element _whose elemental concentration ratio S _164eV / C is 0.001 or more and 0.05 or less, where C (atomic%) is the elemental concentration of C determined on the basis of. The non-aqueous electrolytic solution is at least one compound Y selected from a compound X represented by the following chemical formula (1) and a compound represented by each of the following chemical formulas (2-1) to (2-5) The non-aqueous lithium type storage element according to claim 1, comprising:

{In the formula (1), R ^{1 to} R ⁴ each independently represent a hydrogen atom, a halogen atom, a formyl group, an alkylcarbonyl group having 2 to 7 carbon atoms, a nitrile group, an alkyl group having 1 to 6 carbon atoms, the carbon number It represents an alkoxy group of 1 to 6, an alkylcarbonyloxy group of 2 to 7 carbon atoms, or an alkyloxycarbonyl group of 2 to 7 carbon atoms. }

{Formula ^{(2-1) ~ (2-5) R} 5 ~R 28 in each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, or a halogenated having 1 to 12 carbon atoms Represents an alkyl group; and
N in formulas (2-1) to (2-3) and (2-5) is each independently an integer of 0 to 3. } The compound represented by the chemical formula (1) is thiophene, 2-methylthiophene, 3-methylthiophene, 2-cyanothiophene, 3-cyanothiophene, 2,5-dimethylthiophene, 2-methoxythiophene, 3-methoxythiophene And one or more selected from the group consisting of 2-chlorothiophene, 3-chlorothiophene, 2-acetylthiophene and 3-acetylthiophene,
The compound represented by the chemical formula (2-1) is one or more selected from the group consisting of ethylene sulfate and 1,3-propylene sulfate.
The compound represented by the chemical formula (2-2) is selected from the group consisting of 1,3-propane sultone, 2,4-butane sultone, 1,4-butane sultone, 1,3-butane sultone, and 2,4-pentane sultone One or more selected
The compound represented by the chemical formula (2-3) is one or more selected from the group consisting of 1,3-propene sultone and 1,4-butene sultone,
The compound represented by the above chemical formula (2-4) is 3-sulfurene, and
The compound according to claim 2, wherein the compound represented by the chemical formula (2-5) is at least one selected from the group consisting of ethylene sulfite, propylene 1,2-sulfite, and propylene propylene 1,3-sulfite. Non-aqueous lithium type storage element.   The nonaqueous electrolytic solution according to claim 1, wherein the nonaqueous electrolytic solution contains at least one nonaqueous solvent selected from the group consisting of dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and fluoroethylene carbonate. The non-aqueous lithium type electrical storage element as described in any one of 1-3. The non-aqueous electrolytic solution contains one or more selected from the group consisting of LiPF ₆ and LiBF _4, a non-aqueous lithium-type storage element according to any one of claims 1-4. The nonaqueous electrolytic solution contains LiN _{(SO 2 F)} 2, a non-aqueous lithium-type storage element according to any one of claims 1-5.   The non-aqueous lithium type storage element according to any one of claims 1 to 6, wherein the positive electrode current collector and the negative electrode current collector are respectively non-porous metal foils. The activated carbon contained in the positive electrode active material is derived from pores having a diameter of 20 Å or more and 500 Å or less derived from pores having a diameter of 20 Å or more and 500 Å or less calculated by the V1 (cc / g) and MP methods. When the amount of micropores to be formed is V2 (cc / g), 0.3 <V1 ≦ 0.8 and 0.5 ≦ V2 ≦ 1.0 are satisfied, and the specific surface area measured by the BET method is 1 , including activated carbon showing a 500 meters ² / g or more 3,000 m ² / g or less, a non-aqueous lithium-type storage element according to any one of claims 1-7. The amount of mesopores V1 (cc / g) derived from the pores having a diameter of 20 Å or more and 500 Å or less calculated by the BJH method, the activated carbon contained in the positive electrode active material satisfies 0.8 <V1 ≦ 2.5, MP method The micropore amount V2 (cc / g) derived from the pores having a diameter of less than 20 Å calculated by the formula satisfies 0.8 <V2 ≦ 3.0, and the specific surface area measured by the BET method is 2,300 m ² / The non-aqueous lithium type electrical storage element as described in any one of Claims 1-8 containing the activated carbon which shows g or more and 4,000 m < ² > / g or less.   The non-aqueous lithium type electrical storage element as described in any one of Claims 1-9 in which the said positive electrode active material further contains the transition metal oxide which can occlude and discharge | release lithium ion.   The non-aqueous lithium-type storage element according to claim 10, wherein the transition metal oxide is a transition metal oxide having a structure selected from a layered structure, a spinel structure, and an olivine structure. The transition metal _{oxide, Li x Ni a Co b Al} (1-a-b) O 2 {a and b, respectively, 0.2 <a <0.97,0.2 <b <0.97 Meet. _{}, Li x Ni c Co d} Mn (1-c-d) O 2 {c and d, respectively, satisfy 0.2 <c <0.97,0.2 <d < 0.97. }, Li _x CoO ₂ , Li _x Mn ₂ O ₄ , Li _x FePO ₄ , Li _x MnPO ₄ {x satisfies 0 ≦ x ≦ 1. }, And Li _z V ₂ (PO ₄ ) ₃ {z satisfies 0 ≦ z ≦ 3. The non-aqueous lithium-type storage element according to claim 10 or 11, which is at least one selected from the group consisting of   The negative electrode active material is doped with lithium ions, and the doping amount is 530 mAh / g or more and 2,500 mAh / g or less per unit mass of the negative electrode active material. Nonaqueous lithium type electrical storage element of description. The BET specific surface area of the negative electrode active material is not more than ^{1 m} 2 / g or more 1,500 m ² / g, the non-aqueous lithium-type storage element according to any one of claims 1 to 13.   The non-aqueous lithium type storage element according to claim 13 or 14, wherein the negative electrode active material is in the form of particles, and the average particle diameter thereof is 1 μm or more and 10 μm or less. Ra (Ω) initial internal resistance at cell voltage 4.2 V, electrostatic capacity F (F), electric energy E (Wh), volume of the package containing the electrode assembly V (L) And the internal resistance at an ambient temperature of −10 ° C. is Rb, the following requirements (a), (b) and (c):
(A) The product Ra · F of Ra and F is 0.3 or more and 3.0 or less,
The non-aqueous lithium type storage element according to any one of claims 1 to 15, wherein (b) E / V is 15 or more and 50 or less, and (c) Rb / Ra is 10 or less simultaneously. Assuming that the initial internal resistance at cell voltage 4.2 V is Ra (Ω), cell voltage 4.2 V and environmental temperature 60 ° C. for 2 months and then the internal resistance at 25 ° C. is Rc (Ω), Requirements of (d) and (e):
(D) Rc / Ra is 0.3 or more and 3.0 or less, and (e) the amount of gas generated when stored for 2 months at a cell voltage of 4.2 V and an environmental temperature of 60 ° C. is 30 × at 25 ° C. Less than 10 ^-3 cc / F,
The non-aqueous lithium type electrical storage element as described in any one of Claims 1-16 which satisfy | fills simultaneously. The negative electrode, the positive electrode, the separator, and the non-aqueous electrolyte are contained in an outer layer body,
The non-aqueous lithium type electrical storage element as described in any one of Claims 1-17 whose said exterior body is a metal can or a laminate packaging material.   An electricity storage module comprising the non-aqueous lithium-type electricity storage device according to any one of claims 1 to 18.   A power regeneration system comprising the non-aqueous lithium-type storage element according to any one of claims 1 to 18 or the storage module according to claim 19.   A power load leveling system comprising the non-aqueous lithium-type storage element according to any one of claims 1 to 18 or the storage module according to claim 19.   An uninterruptible power supply system comprising the non-aqueous lithium-type storage element according to any one of claims 1 to 18 or the storage module according to claim 19.   The non-contact electric power feeding system containing the non-aqueous lithium type electrical storage element as described in any one of Claims 1-18, or the electrical storage module as described in Claim 19.   An energy harvesting system comprising the non-aqueous lithium-type storage element according to any one of claims 1 to 18 or the storage module according to claim 19.   A storage system comprising the nonaqueous lithium-type storage element according to any one of claims 1 to 18 or the storage module according to claim 19.