JP4078698B2 - Negative electrode material for non-aqueous secondary battery, method for producing the same, and battery - Google Patents

Description

【００７０】
この結果から基礎酸化物ガラスをチッ化ホウ素との溶融させることで窒素原子を含有せしめた本発明の負極材料は、窒素を含まないものに対して、放電容量と放電電圧は同等で、サイクル性に優れた特性を示すことがわかる。
【００７１】
実施例２
テトラメトキシシラン０．０５モル、ジイソプロピル錫（ＩＶ）０．０５モル、及びＤＭＦ５ｍｌを混合し、これにメタノール５ｍｌ、水５ｍｌ及び０．００１％のアンモニア水１ｍｌの混合液を、攪拌しつつゆっくり滴下した。
この液を４０℃に保温して８時間放置し、その後更に７０℃まで昇温して８時間放置して熟成させた後、得られた含水ゲルをデカンテーションで分離し、次いで濾過し３回水洗した。１２０℃で１２時間、３００℃で３時間乾燥させて得られた塊状のガラスを粉砕機により、平均粒径が約１０ミクロンの粉体に粉砕した。
【００７２】
同様に、表−２に示すゾル形成化合物を用い、同様の工程でそれぞれのガラス粉末を得た。これらをアルミナ製の皿に入れ、電気炉の挿入し減圧した後、アンモニアガスを５０ｍｌ／分の流速で流しつつ４００℃まで昇温し、この温度で１０時間保った。所要時間の後、窒素ガスに切り換えて１０℃／分の割合で室温まで降温し、炉から取り出した。得られた粉末の窒素含有量を表−２に示した。
【００７３】
【表１】

【００７４】
得られた粉末を負極活物質として、正極がＬｉＣｏＯ₂ （８２重量％）と鱗片状黒鉛（８重量％）、アセチレンブラック（４重量％）、テトラフルオロエチレン（６重量％）とから成り、ＬｉＣｏＯ₂ を２００ｍｇ含む１３ｍｍΦのペレットであること以外は実施例１と同様にしてコイン電池を作製した。
また比較用として、それぞれの組成で上記のアンモニア処理を行わないものを負極材料として負極材料とした電池を作成した。
【００７５】
これらのコイン電池を０．７５ｍＡ／ｃｍ² の定電流密度にて、３．８６〜３．０Ｖの範囲で充放電試験を行なった（試験はすべて充電からはじめた。）。その結果を表−３に示した。ここで、サイクル性の指標として充放電を５００回繰り返した後の容量維持率（５００回目の容量／初回の容量）を示した。
【００７６】
【表２】

【００７７】
本発明になるアンモニア処理により、ゾルゲル法で調製した酸化物ガラスに窒素原子が含有されること、この窒素導入により電池性能のうちサイクル性が向上することがわかる。
【００７８】
【発明の効果】
以上から、本発明の錫、亜鉛、鉛、ゲルマニウム、珪素から選ばれる元素の少なくとも１種を含有する酸化物に窒素を導入して成るオキシナイトライド化合物であり、該化合物の窒素／酸素の原子比が０．０１〜３０％である負極材料を用いた電池は、充放電サイクル時の容量維持率が高いことが明らかにされた。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a novel non-aqueous secondary battery having a high discharge potential, a high capacity, good cycleability and storability, and excellent safety.
[0002]
[Prior art]
As a negative electrode material for a non-aqueous secondary battery, lithium metal and lithium alloy are typical, but if they are used, so-called dendrites in which lithium metal grows in a dendritic shape during charge and discharge are generated, causing internal short circuit or Due to the high activity of the dendrite itself, there were dangers such as ignition.
[0003]
In contrast, calcined carbonaceous materials capable of reversibly inserting and releasing lithium have come into practical use. The disadvantage of this carbonaceous material is that it has electrical conductivity, so that lithium metal may be deposited on the carbonaceous material during overcharge or rapid charge, eventually resulting in the deposition of dendritic metal. become. In order to avoid this, the charger is devised or a method of preventing overcharging by reducing the positive electrode active material is adopted, but the latter method limits the amount per active material. Therefore, the discharge capacity is also limited. In addition, since the carbonaceous material has a relatively low density, the discharge capacity is limited in a double sense that the capacity per volume is low.
[0004]
On the other hand, as negative electrode materials that can be expected to have a high discharge capacity other than lithium metal, lithium alloy, and carbonaceous material, JP-A-5-174818, JP-A-6-60867, JP-A-6-275267, and JP-A-6-325765 are disclosed. Japanese Laid-Open Patent Publication No. 6-338324, EP-615296, etc. propose using a composite oxide containing Sn, V, Si, B, Zr, etc. as a negative electrode material. These composite oxides, in combination with a positive electrode of a transition metal compound containing a certain kind of lithium, give a non-aqueous secondary battery with a large discharge capacity of 3 to 3.6 V, and there is almost no dendrite generation in a practical range. High safety. However, in order to realize further improvement in cycleability, it has been desired to further increase the physical strength of the complex oxide, which is a brittle substance.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to obtain a non-aqueous secondary battery having a high discharge voltage, good charge / discharge cycle characteristics, excellent safety, and high energy density.
[0006]
[Means for Solving the Problems]
An object of the present invention, tin, zinc, lead, germanium, oxynitride compounds der formed by introducing nitrogen into the oxide containing at least one element selected from silicon is, of nitrogen / oxygen of the compound A negative electrode material for a non-aqueous secondary battery, wherein the atomic ratio is 0.01 to 30 % .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Although the preferable form of this invention is shown below, this invention is not limited to these.
(1) tin, zinc, lead, germanium, oxynitride compounds der formed by introducing nitrogen into the oxide containing at least one element selected from silicon is, the atomic ratio of nitrogen / oxygen of the compound A negative electrode material for a non-aqueous secondary battery, characterized by being 0.01 to 30 % .
(2) The negative electrode material according to item 1, wherein the negative electrode is an oxynitride compound containing Sn represented by the following general formula (1).
Formula _{(1) SnM p A q O} r N s
( Wherein, M is at least one element selected from the group consisting of Al, B, P, Si, and Ge, and A is at least one element selected from the group consisting of Group 1 elements and Group 2 elements in the Periodic Table) P is a number of 0.2 or more and 3 or less, q is a number of 0 or more and 0.2 or less, r is a number of 1 or more and 6 or less, and s is a number of 0.005 or more and 0.6 or less. )
(3) The negative electrode material according to item 2, wherein an oxynitride compound containing Sn represented by the following general formula (2) is used as the negative electrode.
Formula _{(2) SnSi p1 B p2 P} p3 Al p4 A q O r N s
( A represents at least one element selected from the group consisting of Group 1 elements and Group 2 elements in the Periodic Table, wherein p1, p2, and p3 are 0 or more and 2 or less, respectively, and the total is 0.2 or more. 3 is the number of less, q is 0 to 0.2 in number, r is 1 or more and 6 or less number, s is 0.005 or more, representing the number of 0.6 or less.)
(4) The negative electrode material for a non-aqueous secondary battery, wherein the negative electrode material according to any one of Items 1 to 3 has an amorphous structure.
(5) On the negative electrode sheet containing the negative electrode material as described in any one of items 1 to 3, further comprising a protective layer composed of water-insoluble particles and a binder. Next battery.
(6) formed by adjusting to melt and the oxide and nitride, a manufacturing method of the negative electrode material of claim 1, wherein.
(7) formed by the oxide was heated under an atmosphere of nitrogen and / or ammonia gas, the production method of the negative electrode material according to claim 1, wherein.
[0008]
Hereinafter, the present invention will be described in detail.
General properties of the oxynitride compound in the present invention are described in Sakuka's "Oxynitride Glass" Uchida Otsukuru and New Glass Handbook Editorial Board "New Glass Handbook".
The compound of the present invention contains at least one element selected from tin, zinc, lead, germanium, and silicon. Among them, those containing tin and lead are preferable, and those containing tin are most preferable.
The compound of the present invention can contain any element other than the above-mentioned elements. Among these, alkali and alkaline earth metals are preferably used in addition to phosphorus, silicon, aluminum and zirconium.
[0009]
Although the ratio of nitrogen substitution with respect to the basic oxide is arbitrary, the nitrogen / oxygen atomic ratio is 0.01 to 30%, preferably 1 to 15% nitrogen.
[0010]
The negative electrode material referred to in the present invention is mainly amorphous when assembled into a battery. The term “amorphous” as used herein refers to an X-ray diffraction method using CuKα rays, which has a broad scattering band having an apex from 20 ° to 40 ° as a 2θ value, and has a crystalline diffraction line. Also good. Preferably, the strongest intensity of the crystalline diffraction lines seen at 2θ values of 40 ° or more and 70 ° or less is 500 of diffraction line intensities at the apexes of broad scattering bands seen at 20 ° or more and 40 ° or less of 2θ values. It is preferably not more than twice, more preferably not more than 100 times, particularly preferably not more than 5 times, and most preferably not having a crystalline diffraction line.
[0011]
The oxynitride compound of the present invention can be prepared by melting a basic oxide (an oxide containing no nitrogen is referred to as a basic oxide) and a nitride, or a mixture of a nitride and a raw material of the basic oxide. However, it can be prepared by melting in one step. It can also be prepared by heating the basic oxide glass powder in ammonia gas.
[0012]
For the basic oxide of the present invention, either a melting method or a solution method can be employed. Hereinafter, the synthesis method will be described in detail by taking the melting method as an example. In the melting method, it is preferable that an oxide or compound blended so as to have a target composition is mixed well and then melted to obtain an amorphous composite oxide. The compounds used as raw materials in the melting method and melting conditions are described below.
[0013]
Examples of the Sn compound include SnO, stannous hydroxide, stannic acid, stannous oxalate, stannous phosphate, orthostannic acid, metastannic acid, parastannic acid, stannous fluoride, and stannous chloride. Examples thereof include tin, stannous bromide, stannous iodide, tin selenide, tin telluride, stannous pyrophosphate, tin phosphide, and stannous sulfide.
[0014]
The compounds of Group 1 elements, Group 2 elements, and Group 3 elements of the periodic table include oxides, hydroxides, halides, salts of organic acids such as acetic acid and oxalic acid, and inorganic acids such as hydrochloric acid and phosphoric acid. Can be mentioned. Taking Mg compound as an example, magnesium chloride, magnesium acetate, magnesium oxide, magnesium oxalate, magnesium hydroxide, magnesium stannate, magnesium pyrophosphate, magnesium fluoride, magnesium borofluoride, magnesium phosphate and the like can be used.
[0015]
Examples of the Al compound include aluminum oxide (α-alumina, β-alumina), aluminum silicate, aluminum tri-iso-propoxide, aluminum tellurite, aluminum chloride, aluminum boride, aluminum phosphide, and aluminum phosphate. , Aluminum lactate, aluminum borate, aluminum sulfide, aluminum sulfate, aluminum boride and the like.
Examples of the B compound include boron trioxide, boron trichloride, boron tribromide, boron carbide, boric acid, trimethyl borate, triethyl borate, tripropyl borate, tributyl borate, boron phosphide, and boron phosphate. Etc.
Examples of the P compound include phosphorus pentoxide, phosphorus oxychloride, phosphorus pentachloride, phosphorus trichloride, phosphorus tribromide, trimethyl phosphate, triethyl phosphate, tripropyl phosphate, stannous pyrophosphate, boron phosphate. Etc.
An example of the Si compound is silicon oxide.
[0016]
The base oxide raw material and nitride are mixed and melted in one step, and any nitride can be used when obtaining an oxide containing N element. For example, silicon nitride, aluminum nitride, Examples thereof include silicon nitride, magnesium nitride, lithium nitride, and Si ₂ ON ₂ .
[0017]
As a melting condition, the temperature rising rate is preferably 1 ° C. or more and 200 ° C. or less, more preferably 3 ° C. or more and 200 ° C. or less per minute. It is particularly preferably 5 ° C. or higher and 200 ° C. or lower, and the melting temperature is preferably 500 ° C. or higher and 1700 ° C. or lower, more preferably 600 ° C. or higher and 1600 ° C. or lower, and particularly preferably 700 ° C. or higher and 1500 ° C. or lower. The melting time is preferably 1 hour or more and 100 hours or less, more preferably 1 hour or more and 70 hours or less, and particularly preferably 1 hour or more and 20 hours or less. The temperature is preferably 2 ° C. or higher and 10 ⁷ ° C. or lower, more preferably 5 ° C. or higher and 10 ⁷ ° C. or lower, and particularly preferably 10 ° C. or higher and 10 ⁷ ° C. or lower.
The rate of temperature increase in the present invention is the average rate of temperature rise from 50% of the melting temperature (indicated in ° C) to 80% of the melting temperature (indicated in ° C). This is the average rate of temperature drop from 80% (in ° C) to 50% of the melting temperature (in ° C).
The temperature lowering may be cooled in a firing furnace or taken out of the melting furnace and cooled, for example, in water. In addition, a super rapid cooling method such as the gun method, the Hammer-Anvil method, the slap method, the gas atomizing method, the plasma spray method, the centrifugal quenching method, or the melt drag method described on page 217 of ceramics processing (Gihodo Publishing 1987) can also be used. Moreover, you may cool using the single roller method and the double roller method of New Glass Handbook (Maruzen 1991) p.172. In the case of a material to be melted, the melt may be continuously taken out while supplying the raw material during melting. The melt is preferably stirred.
[0018]
The gas atmosphere when melting the basic oxide glass is mainly composed of an inert gas. Examples of the inert gas include nitrogen, argon, helium, krypton, and xenon. In addition to these inert gases, it is also preferable to flow a gas for controlling the redox state of the melt. These gases include water vapor, hydrogen, carbon dioxide, and carbon monoxide, and are used in combination.
In the melting of the basic oxide glass containing Sn as a functional element, the oxygen partial pressure of the atmospheric gas at the melting temperature should be 10 ⁻⁹ to 10 ⁻¹⁴ atm, preferably 10 ⁻¹⁰ to 10 ⁻¹² atm. Is preferred.
The gas atmosphere for remelting the basic oxide glass and the nitride is preferably an inert gas, and particularly preferably nitrogen gas.
[0019]
Nitrogen element can also be introduced into the basic oxide glass by using ammonia gas as the atmospheric gas on the melt of the basic oxide glass. In this case, it is preferable to stir the melt.
[0020]
Next, the solution method will be described. In order to prepare the basic oxide glass powder by the solution method, after preparing the bulk glass by the sol-gel method, this can be pulverized to obtain the glass powder, or the oxide powder can be directly obtained by the reaction. I can do it.
The preparation method of the basic oxide by the solution method is described in Japanese Patent Application No. 9-148144 and Japanese Patent Application No. 9-270220.
[0021]
Preferred raw materials for use in the solution method include alkoxides such as tetraethoxy tin, diisopropyl tin, diethoxy tin, diethoxy lead, diisopropyl lead, diethoxy zinc, tetramethoxy silicon, trimethoxy boron, trimethoxy phosphine, and cesium alkoxide. In addition, salts such as tin chloride, lead chloride, zinc chloride, and water glass can be used.
[0022]
When the preparation method of heating the basic oxide glass powder in an ammonia gas atmosphere is used as a preparation method of the oxynitride compound of the present invention, the basic oxide may be prepared by a melting method, but prepared by a solution method. Is more preferable.
[0023]
As for the average particle size of the compound shown by this invention, 0.1-60 micrometers is preferable. To obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling air flow type jet mill, a sieve, or the like is used. When pulverizing, wet pulverization in the presence of water or an organic solvent such as methanol can be performed as necessary. In order to make the pulverized particles have a desired particle size, classification is preferably performed. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be used both dry and wet.
[0024]
The compound particles shown in the present invention can be annealed in a vacuum or in an inert gas such as nitrogen, argon, helium, krypton, or xenon. The temperature of the annealing treatment is preferably not higher than the temperature at which particles pulverized at 100 ° C. or higher cause fusion, more preferably 200 to 600 ° C., and most preferably 300 to 500 ° C.
[0025]
Examples of the compounds represented by the general formulas (1) to (3) are shown below, but the present invention is not limited thereto.
SnSiAl _0.2 O3 _. N _0.06 , SnSi _1.2 Al _0.2 O _3.6 N _0.07 , SnSi _1.2 P _0.1 B _0.1 Al _0.2 O _3.6 N _0.07 , SnSiB _{0. 25} Al _0.2 O _3.6 N _0.07 , SnSi _0.63 P _0.25 B _0.38 Al _0.25 O _3.7 N _0.07 , SnSiP _0.1 B _0.1 Al _{0. 4} O _3.9 N _0.07 , SnSiB _0.25 Al _0.2 Zr _0.05 O _3.67 N _0.073 , SnSiB _0.26 Al _0.20 Li _0.10 O _3.6 N _{0. 07} , SnSiB _0.25 Al _0.2 Mg _0.1 O _3.7 N _0.07 , SnSi _1.2 P _0.1 B _0.1 Al _0.1 Zr _0.05 O _3.9 N _{0. 08} , SnSi _0.2 B _0.4 Al _0.4 Mg _0.2 O _3.7 N _0.05 , SnP _0.6 Al _0.6 Li _0.2 O _3.6 N _0.07 , SnSiB _0.25 Al _0.3 Li _0.2 O _3.8 N _0.11 , SnSiB _{0.25 al 0.2 Zr 0.05 Li 0.05 O 3.6} N 0.11, SnSi 1.2 B 0.25 Mg 0.05 O 3.7 N 0.11, ZnSi 1.2 Zr 0.05 O _3.4 N _0.1 , ZnSi _1.2 Mg _0.05 O _3.3 N _0.10 , ZnSi _1.2 B _0.1 Li _0.2 O _3.5 N _0.1 , PbSiB _{0. 3} O _3.4 N _0.034 , PbSiB _0.1 Al _0.1 O _0.33 N _0.03
[0026]
The negative electrode material of the present invention can be used by inserting a light metal, particularly lithium. Examples of the lithium insertion method include an electrochemical method, a chemical method, and a thermal method. One of the preferred methods is an electrochemical method, for example, a small piece of lithium-based metal is pasted on the uncoated portion of the negative electrode mixture of the current collector or on the negative electrode mixture layer, and brought into contact with the electrolytic solution. Can be inserted. In particular, a method of electrochemically inserting lithium in the battery is preferable. It is preferable that the metal piece mainly composed of lithium is pasted in the form of a strip having a thickness of 5 to 200 μm.
[0027]
Lithium can be inserted up to 0.01V, more preferably up to 0.05V when lithium is used as a counter electrode. A particularly preferable method is a method of partially inserting lithium in order to compensate for the irreversible capacity of the negative electrode material, and a method of inserting up to 0.3 V when lithium is used as a counter electrode.
More specifically, the amount of lithium inserted is 0.005 g to 0.5 g, more preferably 0.03 g to 0.2 g, and particularly preferably 0.06 g to 0.15 g per 1 g of the negative electrode material. When the negative electrode material is a metal oxide, the equivalent amount per gram atom of the functional element in the metal oxide is 0.5 to 5.0 equivalents, more preferably 1 to 4.5 equivalents, and particularly preferably 1.2 to 4.2 equivalents. When lithium less than 1.2 equivalents is preliminarily inserted into the negative electrode material, the battery capacity is low, and when more than 4.2 equivalents of lithium is preliminarily inserted, cycle performance is deteriorated.
The amount of lithium inserted can be arbitrarily controlled by the amount of lithium superimposed on the negative electrode sheet. As the metal mainly composed of lithium, lithium metal is preferably used, but a metal having a purity of 90% by weight or more is preferable, and a metal having a purity of 98% by weight or more is particularly preferable. As the overlapping pattern of lithium on the negative electrode sheet, it is preferable to overlap the entire surface of the sheet, but since lithium preliminarily inserted into the negative electrode material gradually diffuses into the negative electrode material due to aging, it is not a full sheet, but a stripe, frame shape Also, any partial overlap of disk-like is preferable. The term “lamination” as used herein means that a metal foil mainly composed of lithium is directly bonded onto a sheet having a negative electrode mixture and an auxiliary layer.
The coverage of the metal foil overlapping in the negative electrode sheet is preferably 10 to 100%, more preferably 15 to 100%, and particularly preferably 20 to 100%. When it is 20% or less, the preliminary insertion of lithium may become uneven, which is not preferable. Further, from the viewpoint of uniformity, the thickness of the metal foil mainly composed of lithium is preferably 5 to 150 μm, more preferably 5 to 100 μm, and particularly preferably 10 to 75 μm.
The handling atmosphere such as cutting and sticking of the metal foil mainly composed of lithium is preferably a dry air or argon gas atmosphere having a dew point of −30 ° C. or lower and −80 ° C. or higher. In the case of dry air, −40 ° C. or lower and −80 ° C. or higher is more preferable. Carbon dioxide gas may be used in combination during handling. Particularly in the case of an argon gas atmosphere, it is preferable to use carbon dioxide in combination.
[0028]
Another preferred method for preliminarily inserting Li into the negative electrode material of the present invention is a method of treating the negative electrode material with a nitrogen-containing solvent solution of metallic lithium described in Japanese Patent Application No. 9-17943. In particular, a liquid ammonia solution is preferably used.
[0029]
Hereinafter, other materials for producing a non-aqueous secondary battery using the negative electrode material of the present invention and a manufacturing method will be described in detail.
The positive and negative electrodes used in the nonaqueous secondary battery of the present invention can be prepared by coating a positive electrode mixture or a negative electrode mixture on a current collector. In addition to the positive electrode active material or the negative electrode material, the positive electrode or the negative electrode mixture can contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively. These electrodes may be disk-shaped or plate-shaped, but are more preferably flexible sheets.
[0030]
The material used for the electrode mixture of the present invention will be described below.
The positive electrode active material used in the present invention is preferably a lithium-containing transition metal oxide. The lithium-containing transition metal oxide is an oxide mainly containing at least one transition metal element selected from Ti, V, Cr, Mn, Fe, Co, Ni, Mo, and W and lithium, This is a compound having a transition metal molar ratio of 0.3 to 2.2.
More preferably, the oxide mainly contains at least one transition metal element selected from V, Cr, Mn, Fe, Co, and Ni and lithium, and the molar ratio of lithium to transition metal is 0.3 to 0.3. It is the compound of 2.2. In addition, Al, Ga, In, Ge, Sn, Pb, Sb, Bi, Si, P, B, or the like may be contained within a range of less than 30 mole percent with respect to the transition metal present mainly.
Further preferred lithium-containing transition metal _{oxides, Li x CoO 2, Li x} NiO 2, Li x MnO 2, Li x Co a Ni 1-a O 2, Li x Co b V 1-b O z, Li x Co _{b Fe 1-b O 2,} Li x Mn 2 O 4, Li x Mn c Co 2-c O 4, Li x Mn c Ni 2-c O 4, Li x Mn c V 2-c O 4, Li x _{Mn c Fe 2-c O 4} ( wherein x = 0.02~1.2, a = 0.1~0.9, b = 0.8~0.98, c = 1.6~1.96 Z = 2.01-2.3).
The most preferred lithium-containing transition metal _{oxides, Li x CoO 2, Li x} NiO 2, Li x MnO 2, Li x Co a Ni 1-a O 2, Li x Mn 2 O 4, Li x Co b V 1 _-b O _z (x = 0.02 to 1.2, a = 0.1 to 0.9, b = 0.9 to 0.98, z = 2.01 to 2.3). In addition, the value of x is a value before the start of charging / discharging and increases / decreases by charging / discharging.
[0031]
The positive electrode active material used in the present invention can be synthesized by a method in which a lithium compound and a transition metal compound are mixed and fired, or by a solution reaction, and the firing method is particularly preferable. Moreover, it is also preferable to synthesize by firing a precursor in which constituent components are uniformly mixed by a solution method. Details for firing are described in paragraph 35 of JP-A-6-60,867, JP-A-7-14,579 and the like, and these methods can be used. The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.
Further, as a method of chemically inserting lithium ions into the transition metal oxide, synthesis is performed by reacting lithium metal, lithium alloy, butyllithium, or a liquid ammonia solution of metal lithium with the transition metal oxide. May be.
[0032]
The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.1 to 50 μm. The volume of particles of 0.5 to 30 μm is preferably 95% or more. More preferably, the volume occupied by a particle group having a particle size of 3 μm or less is 18% or less of the total volume, and the volume occupied by a particle group of 15 μm or more and 25 μm or less is 18% or less of the total volume. No particular limitation is imposed on the specific surface area is preferably 0.01 to 50 m ² / g by the BET method, particularly preferably 0.2m ² / g~1m ² / g. The pH of the supernatant when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less.
[0033]
When the positive electrode active material of the present invention is obtained by firing, the firing temperature is preferably 500 to 1500 ° C, more preferably 700 to 1200 ° C, and particularly preferably 750 to 1000 ° C. The firing time is preferably 4 to 30 hours, more preferably 6 to 20 hours, and particularly preferably 6 to 15 hours.
[0034]
The surface of the positive electrode active material or negative electrode material used in the present invention can be coated with an oxide having a chemical formula different from that of the positive electrode active material or negative electrode material used. The surface oxide is preferably an oxide containing a compound that dissolves both acidic and alkaline. Furthermore, a metal oxide with high electron conductivity is preferable. For example, PbO ₂ , Fe ₂ O ₃ , SnO ₂ , In ₂ O ₃ , ZnO, or the like or a dopant (for example, a metal having a different valence in the oxide, a halogen element, or the like) is preferably included in these oxides. . Particularly preferred are SiO ₂ , SnO ₂ , Fe ₂ O ₃ , ZnO, and PbO ₂ . The amount of the metal oxide used for these surface treatments is preferably 0.1 to 10% by weight, particularly preferably 0.2 to 5% by weight, and preferably 0.3 to 3% per positive electrode active material / negative electrode material. Weight percent is most preferred.
In addition, the surface of the positive electrode active material or the negative electrode material can be modified. For example, the surface of the metal oxide may be treated with an esterifying agent, treated with a chelating agent, treated with a conductive polymer, polyethylene oxide, or the like.
[0035]
The conductive agent used in the mixture of the present invention may be anything as long as it is an electron conductive material that does not cause a chemical change in the constructed battery. Specific examples include natural graphite such as scaly graphite, scaly graphite, earthy graphite, high-temperature fired bodies such as petroleum coke, coal coke, celluloses, saccharides and mesophase pitch, and graphite such as artificial graphite such as vapor-grown graphite. , Carbon blacks such as acetylene black, furnace black, ketjen black, channel black, lamp black, thermal black, etc., carbon materials such as asphalt pitch, coal tar, activated carbon, mesofuse pitch, polyacene, conductivity of metal fibers, etc. Examples thereof include fibers, metal powders such as copper, nickel, aluminum and silver, conductive whiskers such as zinc oxide and potassium titanate, and conductive metal oxides such as titanium oxide. It is preferable to use a graphite plate having an aspect ratio of 5 or more. Among these, graphite and carbon black are preferable, and the particle size is preferably 0.01 μm or more and 20 μm or less, and more preferably 0.02 μm or more and 10 μm or less. These may be used alone or in combination of two or more. When using together, it is preferable to use together carbon blacks, such as acetylene black, and a 1-15 micrometers graphite particle.
The addition amount of the conductive agent to the mixture layer is preferably 1 to 50% by weight, particularly 2 to 30% by weight, based on the negative electrode material or the positive electrode material. In the case of carbon black or graphite, the content is particularly preferably 3 to 20% by weight.
[0036]
In the present invention, a binder is used to hold the electrode mixture. Examples of the binder include polysaccharides, thermoplastic resins, and polymers having rubber elasticity. Preferred binders include starch, carboxymethyl cellulose, cellulose, diacetyl cellulose, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, sodium alginate, polyacrylic acid, polyacrylic acid Na, polyvinyl phenol, polyvinyl methyl ether, polyvinyl alcohol, polyvinyl pyrrolidone. Water-soluble polymers such as polyacrylamide, polyhydroxy (meth) acrylate, styrene-maleic acid copolymer, polyvinyl chloride, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-hexafluoropropylene copolymer, vinylidene furo Ride-tetrafluoroethylene-hexafluoropropylene copolymer, polyethylene, polypropylene, ethylene-propylene (Meth) acrylic acid ester copolymer containing (meth) acrylic acid ester such as thiodiene polymer (EPDM), sulfonated EPDM, polyvinyl acetal resin, methyl methacrylate, 2-ethylhexyl acrylate, (meth) acrylic Acid ester-acrylonitrile copolymer, polyvinyl ester copolymer containing vinyl ester such as vinyl acetate, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, polybutadiene, neoprene rubber, fluororubber, polyethylene oxide, polyester polyurethane Resin, polyether polyurethane resin, polycarbonate polyurethane resin, polyester resin, phenol resin, epoxy resin emulsion (latex) or suspension It can be cited. In particular, polyacrylate ester latex, carboxymethyl cellulose, polytetrafluoroethylene, and polyvinylidene fluoride are exemplified. These binders are preferably those obtained by dispersing fine powders in water, more preferably those having an average particle size of 0.01 to 5 μm in the dispersion, and 0.05 to 1 μm. It is particularly preferable to use one.
These binders can be used alone or in combination. When the amount of the binder added is small, the holding power and cohesion of the electrode mixture is weak. If the amount is too large, the electrode volume increases and the capacity per electrode unit volume or unit weight decreases. For this reason, the addition amount of the binder is preferably 1 to 30% by weight, and particularly preferably 2 to 10% by weight.
[0037]
Any filler can be used as long as it is a fibrous material that does not cause a chemical change in the constructed battery. Usually, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. Although the addition amount of a filler is not specifically limited, 0 to 30 weight% is preferable.
As the ionic conductive agent, those known as inorganic and organic solid electrolytes can be used, and details are described in the section of the electrolytic solution.
A pressure enhancer is a compound that increases the internal pressure of a battery, and carbonates such as lithium carbonate are typical examples.
[0038]
In the current collector that can be used in the present invention, the positive electrode is aluminum, stainless steel, nickel, titanium, or an alloy thereof, and the negative electrode is copper, stainless steel, nickel, titanium, or an alloy thereof. The form of the current collector is foil, expanded metal, punching metal, or wire mesh. In particular, an aluminum foil is preferable for the positive electrode and a copper foil is preferable for the negative electrode.
[0039]
As shown in the examples, by using the negative electrode material of the present invention which is an amorphous nitrogen-containing composite oxide, a battery having a high capacity and good cycleability can be produced. However, these high-capacity batteries can cause an abnormal current to flow due to an external short circuit caused by misuse such as forced discharge, resulting in an accident such as a significant rise in internal temperature, ejection of contents, or rupture of a battery can. is there. In order to prevent these problems, a device such as a safety valve or a current interrupting element such as a PTC has been devised. However, the heat generation is not an essential solution. In the present invention, in order to improve safety, it is preferable to use a combination of the above negative electrode material and the separator described below.
[0040]
As the separator, a material having a high ion permeability, a predetermined mechanical strength, and an insulating microporous or gap is used. Furthermore, in order to improve safety, it is necessary to have a function of blocking the current by closing the gaps at 80 ° C. or higher to increase resistance. The closing temperature of these gaps is 90 ° C. or higher and 180 ° C. or lower, more preferably 110 ° C. or higher and 170 ° C. or lower.
The method of creating the gap differs depending on the material, but any known method may be used. In the case of a porous film, the shape of the hole is usually circular or elliptical, and the size is 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm. Furthermore, it may be a rod-like or irregular-shaped hole as in the case where it is made by a stretching method or a phase separation method. In the case of cloth, the gap is a gap between fibers and depends on how to make a woven fabric or a non-woven fabric. The proportion of these gaps, that is, the porosity, is 20% to 90%, preferably 35% to 80%.
[0041]
The separator of the present invention is a cloth such as a microporous film, a woven fabric or a non-woven fabric having a thickness of 5 μm to 100 μm, more preferably 10 μm to 80 μm.
The separator of the present invention preferably contains at least 20% by weight of an ethylene component, and particularly preferably contains 30% or more. Examples of components other than ethylene include propylene, butene, hexene, ethylene fluoride, vinyl chloride, vinyl acetate, and acetalized vinyl alcohol, with propylene and ethylene fluoride being particularly preferred.
The microporous film is preferably made of polyethylene, ethylene-propylene copolymer or ethylene-butene copolymer. Further, those prepared by mixing and dissolving polyethylene and polypropylene, or polyethylene and polytetrafluoroethylene are also preferred.
Nonwoven fabrics and woven fabrics have a thread diameter of 0.1 to 5 μm, polyethylene, ethylene-propylene copolymer, ethylene-butene 1 copolymer, ethylene-methylbutene copolymer, ethylene-methylpentene copolymer, polypropylene Those made of polytetrafluoroethylene fiber yarn are preferred.
These separators may be a single material or a composite material. In particular, a composite of two or more types of microporous films with different pore sizes, porosity, pore closing temperature, etc., microporous film and nonwoven fabric, microporous film and woven fabric, nonwoven fabric and paper, etc. That is particularly preferred.
The separator of the present invention may contain inorganic fibers such as glass fibers and carbon fibers, and inorganic particles such as silicon dioxide, zeolite, alumina and talc. Further, the voids and the surface may be hydrophilized by treatment with a surfactant.
[0042]
Next, the configuration of the positive and negative electrodes in the present invention will be described. The positive and negative electrodes are preferably in a form in which an electrode mixture is applied to both sides of the current collector. In this case, the number of layers per side may be one or may be composed of two or more layers. When the number of layers per side is 2 or more, the positive electrode active material (or negative electrode material) -containing layer may be 2 or more. A more preferable configuration is a case where the layer is composed of a layer containing a positive electrode active material (or negative electrode material) and a layer not containing a positive electrode active material (or negative electrode material).
The layer that does not contain the positive electrode active material (or the negative electrode material) includes a protective layer for protecting the layer containing the positive electrode active material (or the negative electrode material) and a divided positive electrode active material (or negative electrode material) containing layer. And an undercoat layer between the positive electrode active material (or negative electrode material) -containing layer and the current collector. These are collectively referred to as an auxiliary layer in the present invention.
[0043]
The protective layer is preferably on both the positive and negative electrodes or on the positive and negative electrodes. In the negative electrode, when lithium is inserted into the negative electrode material in the battery, the negative electrode preferably has a protective layer. The protective layer is composed of at least one layer, and may be composed of a plurality of layers of the same type or different types. Moreover, the form which has a protective layer only in the single side | surface of the mixture layers of both surfaces of a collector may be sufficient. These protective layers are composed of water-insoluble particles and a binder. The binder used when forming the above-mentioned electrode mixture can be used as the binder. As the water-insoluble particles, various kinds of conductive particles and organic and inorganic particles having substantially no conductivity can be used. The solubility of water-insoluble particles in water is 100 PPM or less, preferably insoluble.
The proportion of particles contained in the protective layer is preferably 2.5% by weight or more and 96% by weight or less, more preferably 5% by weight or more and 95% by weight or less, and particularly preferably 10% by weight or more and 93% by weight or less.
[0044]
Examples of water-insoluble conductive particles include carbon particles such as metals, metal oxides, metal fibers, carbon fibers, carbon black, and graphite. Among these water-insoluble conductive particles, those having low reactivity with alkali metals, particularly lithium, are preferable, and metal powders and carbon particles are more preferable. The electrical resistivity at 20 ° C. of the elements constituting the particles is preferably 5 × 10 ⁹ Ω · m or less.
[0045]
As the metal powder, a metal having low reactivity with lithium, that is, a metal that is difficult to form a lithium alloy is preferable. Specifically, copper, nickel, iron, chromium, molybdenum, titanium, tungsten, and tantalum are preferable. The shape of these metal powders may be any of acicular, columnar, plate-like, and massive shapes, and the maximum diameter is preferably 0.02 μm or more and 20 μm or less, more preferably 0.1 μm or more and 10 μm or less. These metal powders are preferably those whose surfaces are not excessively oxidized, and when oxidized, heat treatment is preferably performed in a reducing atmosphere.
[0046]
As the carbon particles, a known carbon material used as a conductive material used in combination when the electrode active material is not conductive can be used. Specifically, a conductive agent used for making an electrode mixture is used.
[0047]
Examples of the water-insoluble particles having substantially no conductivity include fine powder of Teflon, SiC, aluminum nitride, alumina, zirconia, magnesia, mullite, forsterite, and steatite. These particles may be used in combination with conductive particles, and are preferably used in an amount of 0.01 to 10 times that of the conductive particles.
[0048]
The positive (negative) electrode sheet can be prepared by applying a positive (negative) electrode mixture onto a current collector, drying, and compressing.
The mixture is prepared by mixing a positive electrode active material (or negative electrode material) and a conductive agent, adding a binder (suspension or emulsion of resin powder) and a dispersion medium, kneading and mixing, It can be carried out by dispersing with a mixer / disperser such as a mixer, homogenizer, dissolver, planetary mixer, paint shaker or sand mill. As the dispersion medium, water or an organic solvent is used, but water is preferable. In addition, additives such as a filler, an ionic conductive agent, and a pressure enhancer may be added as appropriate. The pH of the dispersion is preferably 5 to 10 for the negative electrode and 7 to 12 for the positive electrode.
[0049]
Application can be performed by various methods, for example, reverse roll method, direct roll method, blade method, knife method, extrusion method, slide method, curtain method, gravure method, bar method, dip method and squeeze method. I can list them. A method using an extrusion die and a method using a slide coater are particularly preferred. The application is preferably performed at a speed of 0.1 to 100 m / min. Under the present circumstances, the surface state of a favorable coating layer can be obtained by selecting the said application | coating method according to the liquid physical property of a mixture paste, and drying property. When the electrode layer is a plurality of layers, it is preferable to apply the plurality of layers at the same time from the viewpoint of uniform electrode production, production cost, and the like. The thickness, length and width of the coating layer are determined by the size of the battery. The thickness of a typical coating layer is 10 to 1000 μm in a compressed state after drying.
The electrode sheet after application is dried and dehydrated by the action of hot air, vacuum, infrared rays, far infrared rays, electron beams and low-humidity air. These methods can be used alone or in combination. The drying temperature is preferably in the range of 80 to 350 ° C, particularly preferably in the range of 100 to 260 ° C. The water content after drying is preferably 2000 ppm or less, and more preferably 500 ppm or less.
For the compression of the electrode sheet, a generally employed pressing method can be used, but a die pressing method and a calendar pressing method are particularly preferable. The press pressure is not particularly limited, but is preferably 10 kg / cm ^{2 to 3} t / cm ² . The press speed of the calendar press method is preferably 0.1 to 50 m / min. The pressing temperature is preferably room temperature to 200 ° C.
[0050]
The electrolytic solution is generally composed of a supporting salt and a solvent. Lithium salt is mainly used as the supporting salt in the lithium secondary battery.
The lithium salt can be used in the present invention, for example, fluoro represented by _{LiClO 4, LiBF 4, LiPF 6} , LiCF 3 CO 2, LiAsF 6, LiSbF 6, LiB 10 Cl 10, LiOSO 2 C n F 2n + 1 Imide salts represented by sulfonic acid (n is a positive integer of 6 or less), LiN (SO ₂ C _n F _{2n + 1} ) (SO ₂ C _m F _{2m + 1} ) (m and n are each 6 or less positive) ), LiN (SO ₂ C _p F _{2p + 1} ) (SO ₂ C _q F _{2q + 1} ) (SO ₂ C _r F _{2r + 1} ), and each of the metide salts (p, q, r is 6). The following positive integers), Li aliphatic salts such as lithium lithium carboxylate, LiAlCl ₄ , LiCl, LiBr, LiI, chloroborane lithium, lithium tetraphenylborate, etc. can be raised, and one or more of these can be mixed Can be used. Of these, a solution in which LiBF ₄ and / or LiPF ₆ is dissolved is preferable.
The concentration of the supporting salt is not particularly limited, but is preferably 0.2 to 3 mol per liter of the electrolytic solution.
[0051]
Solvents that can be used in the present invention include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl formate, methyl acetate, 1,2-dimethoxyethane, tetrahydrofuran, and 2-methyl. Tetrahydrofuran, dimethyl sulfoxide, 1,3-dioxolane, formamide, dimethylformamide, dioxolane, dioxane, acetonitrile, nitromethane, ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, Aprotic such as propylene carbonate derivative, tetrahydrofuran derivative, ethyl ether, 1,3-propane sultone Machine solvent can be cited, to use a mixture of alone or in combination. Among these, carbonate-based solvents are preferable, and it is particularly preferable to use a mixture of a cyclic carbonate and an acyclic carbonate. As the cyclic carbonate, ethylene carbonate and propylene carbonate are preferable. Moreover, as an acyclic carbonate, diethyl carbonate, dimethyl carbonate, and methyl ethyl carbonate are preferable.
Examples of the electrolytic solution that can be used in the present invention include LiCF ₃ SO ₃ , LiClO ₄ , LiBF ₄ and / or LiPF ₆ in an electrolytic solution in which ethylene carbonate, propylene carbonate, 1,2-dimethoxyethane, dimethyl carbonate or diethyl carbonate is appropriately mixed. An electrolytic solution containing is preferable. In particular, an electrolysis containing at least one salt selected from LiCF ₃ SO ₃ , LiClO ₄ , or LiBF ₄ and LiPF ₆ in a mixed solvent of at least one of propylene carbonate or ethylene carbonate and at least one of dimethyl carbonate or diethyl carbonate. Liquid is preferred. The amount of the electrolyte added to the battery is not particularly limited, and can be used depending on the amount of the positive electrode material or the negative electrode material or the size of the battery.
[0052]
In addition to the electrolytic solution, the following solid electrolyte can be used in combination.
The solid electrolyte is classified into an inorganic solid electrolyte and an organic solid electrolyte.
Well-known inorganic solid electrolytes include Li nitrides, halides, oxyacid salts, and the like. Among _{them, Li 3 N, LiI, Li} 5 NI 2, Li 3 N-LiI-LiOH, Li 4 SiO 4, Li 4 SiO 4 -LiI-LiOH, x Li 3 PO 4 - (1-x) Li 4 SiO ₄ , Li ₂ SiS ₃ , phosphorus sulfide compounds and the like are effective.
[0053]
In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion dissociation group, a mixture of a polymer containing an ion dissociation group and the above aprotic electrolyte, phosphoric acid A polymer matrix material containing an ester polymer and an aprotic polar solvent is effective. Furthermore, there is a method of adding polyacrylonitrile to the electrolytic solution. A method of using an inorganic and organic solid electrolyte in combination is also known.
[0054]
Further, other compounds may be added to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine, pyrroline, pyrrole, triphenylamine, phenylcarbazole, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-glyme, hexaphosphoric triamide, nitrobenzene derivative, sulfur, quinoneimine dye, N-substituted oxazolidinone and N , N′-substituted imidazolidinone, ethylene glycol dialkyl ether, quaternary ammonium salt, polyethylene glycol, pyrrole, 2-methoxyethanol, AlCl ₃ , conductive polymer electrode active material monomer, triethylene phosphoramide, trialkylphosphine, Morpholine, aryl compounds having a carbonyl group, crown ethers such as 12-crown-4, hexamethylphosphoric triamide and 4-alkylmorpholine Bicyclic tertiary amines, oils, quaternary phosphonium salts, and the like tertiary sulfonium salt. Particularly preferred is a case where triphenylamine and phenylcarbazole are used alone or in combination.
[0055]
In order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolyte. In addition, carbon dioxide gas can be included in the electrolyte in order to make it suitable for high-temperature storage.
[0056]
It is desirable that the electrolytic solution contains as little water and free acid as possible. For this reason, the raw material of the electrolytic solution is preferably one that has been sufficiently dehydrated and purified. The electrolyte solution is preferably adjusted in dry air or an inert gas with a dew point of minus 30 ° C. or less. The amount of water and free acid content in the electrolytic solution is 0.1 to 500 ppm, more preferably 0.2 to 100 ppm.
[0057]
The entire amount of the electrolytic solution may be injected once, but it is preferable to inject it in two or more times. When injecting in two or more times, each solution may have the same composition but a different composition (for example, a non-aqueous solvent or a non-aqueous solvent having a higher viscosity than the solvent after injecting a solution of a lithium salt in a non-aqueous solvent). Or a solution in which a lithium salt is dissolved in a solvent or a nonaqueous solvent may be injected). In order to shorten the time for injecting the electrolyte, etc., the battery can may be decompressed, or centrifugal force or ultrasonic waves may be applied to the battery can.
[0058]
Battery cans and battery lids that can be used in the present invention are nickel-plated steel and stainless steel plates (SUS304, SUS304L, SUS304N, SUS316, SUS316L, SUS430, SUS444, etc.), nickel-plated stainless steel plates (same as above) , Aluminum or an alloy thereof, nickel, titanium, and copper, and the shapes are a true circular cylinder, an elliptical cylinder, a square cylinder, and a rectangular cylinder. In particular, when the outer can also serves as the negative electrode terminal, a stainless steel plate and a nickel-plated steel plate are preferable, and when the outer can also serves as the positive electrode terminal, a stainless steel plate, aluminum, or an alloy thereof is preferable. The shape of the battery can may be any of buttons, coins, sheets, cylinders, and corners.
A safety valve can be used for the sealing plate as a countermeasure against an increase in the internal pressure of the battery can. In addition, a method of cutting a member such as a battery can or a gasket can be used. In addition, various conventionally known safety elements (for example, fuses, bimetals, PTC elements, etc. as overcurrent prevention elements) may be provided.
[0059]
For the lead plate used in the present invention, a metal having electrical conductivity (for example, iron, nickel, titanium, chromium, molybdenum, copper, aluminum, etc.) or an alloy thereof can be used. As a welding method for the battery lid, battery can, electrode sheet, and lead plate, a known method (eg, direct current or alternating current electric welding, laser welding, ultrasonic welding) can be used. As the sealing agent for sealing, a conventionally known compound or mixture such as asphalt can be used.
[0060]
Gaskets that can be used in the present invention are olefin polymers, fluoropolymers, cellulosic polymers, polyimides, and polyamides as materials. Olefin polymers are preferred from the viewpoint of organic solvent resistance and low moisture permeability, and are mainly composed of propylene. Polymers are preferred. Furthermore, a block copolymer of propylene and ethylene is preferable.
[0061]
The battery assembled as described above is preferably subjected to an aging treatment. The aging treatment includes pre-treatment, activation treatment, post-treatment, and the like, whereby a battery with high charge / discharge capacity and excellent cycleability can be produced. The pretreatment is a treatment for homogenizing the distribution of lithium in the electrode. For example, control of lithium dissolution, temperature control to make the lithium distribution uniform, oscillation and / or rotation treatment, optional charging / discharging A combination is made. The activation process is a process for inserting lithium into the negative electrode of the battery body, and it is preferable to insert 50 to 120% of the amount of lithium inserted during actual use charging of the battery. The post-processing is processing for sufficient activation processing, and includes storage processing for uniform battery reaction and charge / discharge processing for determination, which can be arbitrarily combined.
[0062]
The battery of the present invention is covered with an exterior material as necessary. Examples of the exterior material include a heat-shrinkable tube, an adhesive tape, a metal film, paper, cloth, paint, and a plastic case. Further, at least a part of the exterior may be provided with a portion that changes color by heat so that the heat history during use can be known.
[0063]
A plurality of the batteries of the present invention are assembled in series and / or in parallel as needed, and stored in a battery pack. In addition to safety elements such as positive temperature coefficient resistors, temperature fuses, fuses and / or current interrupting elements, the battery pack also requires safety circuits (monitoring the voltage, temperature, current, etc. of each battery and / or the entire battery pack) In this case, a circuit having a function of interrupting current may be provided. In addition to the positive and negative terminals of the entire assembled battery, the battery pack should be provided with the positive and negative terminals of each battery, the entire assembled battery, the temperature detection terminal of each battery, the current detection terminal of the entire assembled battery, etc. as external terminals. You can also. The battery pack may incorporate a voltage conversion circuit (such as a DC-DC converter). The connection of each battery may be fixed by welding a lead plate, or may be fixed so that it can be easily attached and detached with a socket or the like. Further, the battery pack may be provided with display functions such as the remaining battery capacity, the presence / absence of charging, and the number of uses.
[0064]
The battery of the present invention is used in various devices. In particular, video movies, portable video decks with built-in monitors, movie cameras with built-in monitors, digital cameras, compact cameras, single-lens reflex cameras, film with lenses, notebook computers, notebook word processors, electronic notebooks, mobile phones, cordless phones, bearded scorpions, It is preferably used for electric tools, electric mixers, automobiles and the like.
[0065]
【Example】
Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples unless it exceeds the gist of the invention.
Example 1
Synthesis of negative electrode material A raw material batch having the following composition was placed in a high-purity alumina crucible, and an atmospheric gas adjusted to 10 ⁻¹² atm at 1100 ° C. with argon / carbon dioxide gas / hydrogen was allowed to flow, The temperature was raised to 1100 ° C., and the mixture was further melted for 10 hours under a pure nitrogen atmosphere, and then cooled to room temperature at 10 ° C./min to obtain a yellow transparent glass lump.
[0066]
Sn0 107.8g
SiO ₂ 48.1g
Al ₂ O ₃ 5.1 g
B ₂ O ₃ 7.0 g
After coarsely pulverizing this, it was made into a powder having an average particle size of about 20 μm by a jet mill. 1 kg of this oxide glass was mixed with 18 g of boron nitride, filled in an alumina crucible, melted at 1000 ° C. for 3 hours in a pure nitrogen atmosphere, and then cooled at 10 ° C./10 minutes.
As a result of analyzing the obtained glass, the nitrogen atom contained about 2% with respect to the oxygen atom.
After this glass was coarsely pulverized, it was made into a powder having an average particle diameter of 8 μm with a jut mill, and a coin battery was produced by using this as a negative electrode material.
[0067]
The negative electrode material was applied as a coating solution having the following composition and coated on a 10 μm thick copper current collector sheet.
Negative electrode material 85% by weight
Graphite 6% by weight
PVDF 9% by weight
N-methylpyrrolidone 9% by weight
The obtained negative electrode sheet was punched out to 15 mmΦ, and a Li-Al alloy electrode was used as a counter electrode to prepare a coin battery A using an EC / DC (1: 1) electrolyte solution containing 1M-LiPF ₆ .
For comparison, a coin battery B was produced in the same manner with respect to a sample obtained by adding boron oxide instead of boron nitride and remelting.
[0068]
These coin batteries were subjected to a charge / discharge test at a constant current density of 0.75 mA / cm ² in a range of 0.05 to 0.9 V (all tests were started from discharge). The results are shown in Table 1.
The abbreviations shown in Table 1 are: (a) first discharge capacity (mAh per 1 g of negative electrode material), (b) discharge average voltage (V), (c) charge / discharge cycle characteristics (first discharge capacity The number of cycles at which the capacity reaches 60%) is shown.
[0069]

[0070]
From this result, the negative electrode material of the present invention containing nitrogen atoms by melting the basic oxide glass with boron nitride has the same discharge capacity and discharge voltage as those containing no nitrogen, and has cycle characteristics. It can be seen that it exhibits excellent characteristics.
[0071]
Example 2
Tetramethoxysilane 0.05 mol, diisopropyl tin (IV) 0.05 mol, and DMF 5 ml were mixed, and a mixture of methanol 5 ml, water 5 ml and 0.001% ammonia water 1 ml was slowly added dropwise with stirring. did.
This liquid was kept at 40 ° C. and allowed to stand for 8 hours, then further heated to 70 ° C. and left to age for 8 hours, and then the obtained hydrogel was separated by decantation, and then filtered three times. Washed with water. The massive glass obtained by drying at 120 ° C. for 12 hours and at 300 ° C. for 3 hours was pulverized by a pulverizer into a powder having an average particle diameter of about 10 microns.
[0072]
Similarly, each glass powder was obtained in the same process using the sol-forming compounds shown in Table-2. These were put in an alumina dish, and after inserting an electric furnace and depressurizing, the temperature was raised to 400 ° C. while flowing ammonia gas at a flow rate of 50 ml / min, and kept at this temperature for 10 hours. After the required time, the gas was switched to nitrogen gas, cooled to room temperature at a rate of 10 ° C./min, and taken out of the furnace. The nitrogen content of the obtained powder is shown in Table-2.
[0073]
[Table 1]

[0074]
Using the obtained powder as a negative electrode active material, the positive electrode was composed of LiCoO ₂ (82 wt%), flaky graphite (8 wt%), acetylene black (4 wt%), tetrafluoroethylene (6 wt%), and LiCoO _A coin battery was fabricated in the same manner as in Example 1 except that it was a 13 mmφ pellet containing 200 mg of ₂ .
Moreover, the battery which made the negative electrode material the thing which does not perform said ammonia treatment with each composition as a negative electrode material was created for comparison.
[0075]
These coin batteries were subjected to a charge / discharge test in the range of 3.86 to 3.0 V at a constant current density of 0.75 mA / cm ² (all tests started from charging). The results are shown in Table-3. Here, the capacity retention ratio (500th capacity / first capacity) after 500 charge / discharge cycles was shown as an index of cycle performance.
[0076]
[Table 2]

[0077]
It can be seen that by the ammonia treatment according to the present invention, nitrogen atoms are contained in the oxide glass prepared by the sol-gel method, and the cycle performance of the battery performance is improved by this nitrogen introduction.
[0078]
【The invention's effect】
From the above, the present invention tin, zinc, lead, germanium, oxynitride compounds der formed by introducing nitrogen into the oxide containing at least one element selected from silicon is, of nitrogen / oxygen of the compound It has been clarified that a battery using a negative electrode material having an atomic ratio of 0.01 to 30 % has a high capacity retention rate during a charge / discharge cycle.

Claims (7)

Tin, zinc, lead, germanium, oxynitride compounds der formed by introducing nitrogen into the oxide containing at least one element selected from silicon is, the atomic ratio of nitrogen / oxygen of the compound is 0.01 A negative electrode material for a non-aqueous secondary battery, which is ˜30% . The negative electrode material according to claim 1, wherein an oxynitride compound containing Sn represented by the following general formula (1) is used as the negative electrode.
Formula _{(1) SnM p A q O} r N s
( Wherein, M is at least one element selected from the group consisting of Al, B, P, Si, and Ge, and A is at least one element selected from the group consisting of Group 1 elements and Group 2 elements in the Periodic Table) P is a number of 0.2 or more, 3 or less, q is a number of 0 or more and 0.2 or less, r is a number of 1 or more and 6 or less, and s is a number of 0.005 or more and 0.6 or less. ) The negative electrode material according to claim 2, wherein an oxynitride compound containing Sn represented by the following general formula (2) is used as the negative electrode.
Formula _{(2) SnSi p1 B p2 P} p3 Al p4 A q O r N s
( A represents at least one element selected from the group consisting of Group 1 elements and Group 2 elements in the Periodic Table, wherein p1, p2, and p3 are 0 or more and 2 or less, respectively, and the total is 0.2 or more. 3 is the number of less, q is 0 to 0.2 in number, r is 1 or more and 6 or less number, s is 0.005 or more, representing the number of 0.6 or less.) 4. The negative electrode material for non-aqueous secondary battery, wherein the negative electrode material according to claim 1 has an amorphous structure. A non-aqueous secondary battery comprising a protective layer further comprising water-insoluble particles and a binder on the negative electrode sheet containing the negative electrode material according to claim 1. . Formed by adjusting by melting and the oxide and nitride, a manufacturing method of the negative electrode material according to claim 1, wherein. Comprising the oxide was heated under an atmosphere of nitrogen and / or ammonia gas, the production method of the negative electrode material according to claim 1, wherein.