JP2007329010A - Electrode for lithium secondary battery, and its manufacturing method - Google Patents
Electrode for lithium secondary battery, and its manufacturing method Download PDFInfo
- Publication number
- JP2007329010A JP2007329010A JP2006159099A JP2006159099A JP2007329010A JP 2007329010 A JP2007329010 A JP 2007329010A JP 2006159099 A JP2006159099 A JP 2006159099A JP 2006159099 A JP2006159099 A JP 2006159099A JP 2007329010 A JP2007329010 A JP 2007329010A
- Authority
- JP
- Japan
- Prior art keywords
- thin film
- active material
- electrode
- lithium secondary
- alloy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Abstract
Description
本発明は、リチウム二次電池用電極及びその製造方法に関するものである。特に、充放電に伴う電池容量の低下を抑制することができるリチウム二次電池用電極及びその製造方法に関するものである。 The present invention relates to an electrode for a lithium secondary battery and a method for producing the same. In particular, the present invention relates to an electrode for a lithium secondary battery that can suppress a decrease in battery capacity due to charge and discharge, and a method for manufacturing the same.
リチウム二次電池は、長寿命・高効率・高容量であり、携帯電話、ノートパソコン、デジタルカメラなどの電源としてその需要は益々拡大している。そして、リチウム二次電池のさらなる高性能化を目指して、活物質や集電体の研究開発が活発に行われている。 Lithium secondary batteries have a long life, high efficiency, and high capacity, and the demand for them as power sources for mobile phones, notebook computers, digital cameras, etc. is increasing. Research and development of active materials and current collectors are actively conducted with the aim of further improving the performance of lithium secondary batteries.
リチウム二次電池は、正極と負極との間でLiイオンをやり取りすることによって、充放電が行われる。最近では、このリチウム二次電池の活物質にLiを吸蔵して合金化するシリコン（Si）やスズ（Sn）等を用いることが提案されている。具体的には、このような活物質を薄膜として集電体上に形成し、この薄膜にLiを吸蔵・放出させることで電池の充放電を行うようにする。しかし、このような活物質は充放電の際にLiの吸蔵・放出に伴い体積が膨張・収縮し、薄膜自身の体積変化により薄膜が集電体から剥離するという問題があった。このような電極を用いたリチウム二次電池は、充放電の繰り返しに伴い電池容量が低下してしまうので、良好な充放電サイクル特性が得られなかった。 The lithium secondary battery is charged and discharged by exchanging Li ions between the positive electrode and the negative electrode. Recently, it has been proposed to use silicon (Si), tin (Sn), or the like that occludes Li to form an alloy in the active material of the lithium secondary battery. Specifically, such an active material is formed on a current collector as a thin film, and charging / discharging of the battery is performed by inserting and extracting Li in this thin film. However, such an active material has a problem that the volume expands and contracts with the insertion and extraction of Li during charge and discharge, and the thin film peels off from the current collector due to the volume change of the thin film itself. Since the lithium secondary battery using such an electrode has a reduced battery capacity with repeated charge and discharge, good charge / discharge cycle characteristics could not be obtained.
この膨張・収縮を抑制するために、例えば特許文献１に記載のリチウム二次電池用電極が提案されている。このリチウム二次電池用電極は、Liと合金化する金属（Sn）と、Liと合金化しない金属（Co等）とからなる合金薄膜（Sn-Co合金等）が集電体上に形成されている。また、この合金薄膜は、電解メッキ法を用いて集電体上に形成する。この特許文献１によれば、このような電極を用いたリチウム二次電池は、良好な充放電サイクル特性を有することが示されている。中でもLiと合金化しない金属にCo又はNiを用いたSn-Co合金薄膜、Sn-Ni合金薄膜、Sn-Ni-Co合金薄膜が形成された電極がより良好な充放電サイクル特性を有している。 In order to suppress this expansion / contraction, for example, an electrode for a lithium secondary battery described in Patent Document 1 has been proposed. In this lithium secondary battery electrode, an alloy thin film (Sn-Co alloy, etc.) composed of a metal (Sn) alloyed with Li and a metal (Co etc.) not alloyed with Li is formed on the current collector. ing. The alloy thin film is formed on the current collector using an electrolytic plating method. According to this Patent Document 1, it is shown that a lithium secondary battery using such an electrode has good charge / discharge cycle characteristics. In particular, Sn-Co alloy thin films using Sn or Co, Ni or Sn-Ni-Co alloy thin films using metals that do not alloy with Li have better charge / discharge cycle characteristics. Yes.
しかし、特許文献１に示されるように、Liと合金化しない金属にFeのみを用いた場合、合金薄膜の膨張・収縮を十分に抑制することができず、電池の容量維持率を十分に維持できていない。また、Feと比較して高価なCo又はNiを用いた上記合金薄膜では、Co又はNiを合わせて20重量％程度含有する必要があり、リチウム二次電池用電極のコストを低く抑えることが難しい。 However, as shown in Patent Document 1, when only Fe is used as a metal that is not alloyed with Li, the expansion and contraction of the alloy thin film cannot be sufficiently suppressed, and the capacity retention rate of the battery is sufficiently maintained. Not done. In addition, the alloy thin film using Co or Ni, which is more expensive than Fe, needs to contain about 20% by weight of Co or Ni, and it is difficult to keep the cost of the lithium secondary battery electrode low. .
本発明は上記の事情に鑑みてなされたものであり、その目的の一つは、Liと合金化しない金属にFeを用いて、充放電に伴う電池容量の低下を抑制することができるリチウム二次電池用電極を提供することにある。また、本発明の別の目的は、Liと合金化しない金属にFeを用いて、充放電に伴う電池容量の低下を抑制することができるリチウム二次電池用電極の製造方法を提供することにある。 The present invention has been made in view of the above circumstances, and one of its purposes is to use lithium as a metal that is not alloyed with Li to suppress a decrease in battery capacity due to charge and discharge. The object is to provide an electrode for a secondary battery. Another object of the present invention is to provide a method for producing an electrode for a lithium secondary battery that can suppress a decrease in battery capacity due to charge / discharge using Fe as a metal that is not alloyed with Li. is there.
本発明者らは、Liを吸蔵・放出する活物質にFeを主成分とする複数種のLiと合金化しない金属を添加した活物質薄膜を集電体上に形成して、種々のリチウム二次電池用電極を作製し、各電極の性能評価を行った。その結果、本発明者らは、Feの他に、Ni又はCoの一方を添加するのではなく、NiとCoの両方を添加すると共に、活物質薄膜に含有するFe、Ni、Coの濃度を各々規定することで、Feのみを添加する場合と比較して充放電に伴う電池容量の低下を効果的に抑制できるとの知見を得た。 The inventors of the present invention formed an active material thin film on a current collector by adding, to an active material that occludes and releases Li, a plurality of types of metals that are mainly composed of Fe and non-alloyed metals, on a current collector. Secondary battery electrodes were prepared and the performance of each electrode was evaluated. As a result, the present inventors did not add either Ni or Co in addition to Fe, but added both Ni and Co, and at the same time, adjusted the concentrations of Fe, Ni, and Co contained in the active material thin film. It was found that by defining each of them, a decrease in battery capacity due to charging / discharging can be effectively suppressed as compared with the case of adding only Fe.
本発明のリチウム二次電池用電極は、集電体上にLiを吸蔵・放出する活物質とFeとを含有する活物質薄膜が形成されている。さらに、この活物質薄膜はFeの他にNi、Coを含有しており、活物質薄膜に含有するFe、Ni、Coの濃度は各々、重量％で10％＜Fe＜30％、1％＜Ni＜4％、1％＜Co＜3％の範囲を満たすことを特徴とする。 In the electrode for a lithium secondary battery of the present invention, an active material thin film containing Fe and an active material that absorbs and releases Li is formed on a current collector. Further, this active material thin film contains Ni and Co in addition to Fe, and the concentrations of Fe, Ni and Co contained in the active material thin film are 10% <Fe <30%, 1% < Ni <4% and 1% <Co <3% are satisfied.
Fe、Ni、CoはいずれもLiと合金化しない金属であり、充放電の際に膨張・収縮することがない。活物質薄膜がこのような金属を含有することで、Liの吸蔵・放出に伴う活物質薄膜の膨張・収縮程度が緩和され、活物質薄膜が集電体から剥離することを抑制することができる。特に、活物質薄膜に含有するFe、Ni、Coの濃度が各々上記に規定する範囲を満たす場合、十分な電池容量を有しかつ良好な充放電サイクル特性を有するリチウム二次電池用電極を得ることができる。Fe、Ni、Coの濃度が各々上記に規定する下限値以下の場合には、充放電の際に活物質薄膜の膨張・収縮を十分に緩和することができず、十分な効果が得られない。逆に、上限値以上の場合には、活物質の濃度が相対的に低くなるため、電池容量の低下が顕著となり好ましくない。 Fe, Ni, and Co are all metals that are not alloyed with Li, and do not expand or contract during charge and discharge. By containing such a metal in the active material thin film, the degree of expansion / contraction of the active material thin film accompanying the insertion and extraction of Li can be reduced, and the active material thin film can be prevented from peeling from the current collector. . In particular, when the concentrations of Fe, Ni, and Co contained in the active material thin film satisfy the ranges specified above, an electrode for a lithium secondary battery having sufficient battery capacity and good charge / discharge cycle characteristics is obtained. be able to. When the Fe, Ni, and Co concentrations are each lower than the lower limit specified above, the expansion and contraction of the active material thin film cannot be sufficiently relaxed during charging and discharging, and sufficient effects cannot be obtained. . On the other hand, when the value is equal to or higher than the upper limit value, the concentration of the active material becomes relatively low, which is not preferable because the battery capacity is significantly reduced.
Liを吸蔵・放出する活物質としては、例えばLiと合金化する金属が好適であり、より具体的には、Si、Sn、Ge、Al、Pb等が挙げられる。特にSiが好適に利用できる。 As the active material that occludes and releases Li, for example, a metal alloyed with Li is suitable, and more specifically, Si, Sn, Ge, Al, Pb, and the like can be given. In particular, Si can be suitably used.
集電体としては、例えばLiと合金化しない金属が好適であり、より具体的には、Cu、Ni、少なくともこれら一つを含む合金等が挙げられる。中でもCuが好適に利用できる。また、集電体は薄くてもよく、集電体にCuを用いる場合は圧延銅箔や電解銅箔を利用することができる。 As the current collector, for example, a metal that is not alloyed with Li is suitable, and more specifically, Cu, Ni, an alloy containing at least one of these, and the like can be given. Among these, Cu can be suitably used. Further, the current collector may be thin, and when Cu is used for the current collector, a rolled copper foil or an electrolytic copper foil can be used.
本発明のリチウム二次電池用電極は、例えば以下の構成を具える本発明の製造方法により作製することができる。本発明の製造方法は、Ni、Coの濃度が重量％で20％＜Ni＜40％、10％＜Co＜30％の範囲を満たし、残部がFeであるFe-Ni-Co合金を用意する第一工程と、前記合金の配合割合が重量％で20％＜Fe-Ni-Co合金＜50％となるように、活物質と前記合金とを混合する第二工程と、前記工程により得られた薄膜原料を気相法により集電体上に成膜することで、活物質薄膜を形成する第三工程とを具えることを特徴とする。 The electrode for a lithium secondary battery of the present invention can be produced, for example, by the production method of the present invention having the following configuration. The production method of the present invention provides a Fe—Ni—Co alloy in which the concentration of Ni and Co satisfies the ranges of 20% <Ni <40% and 10% <Co <30% in weight%, and the balance is Fe. Obtained by the first step, the second step of mixing the active material and the alloy such that the blending ratio of the alloy is 20% <Fe-Ni-Co alloy <50% by weight%, and the step. And a third step of forming an active material thin film by depositing the thin film raw material on the current collector by a vapor phase method.
この構成によれば、集電体上に形成される活物質薄膜に含有するFe、Ni、Coの各々の濃度が、重量％で10％＜Fe＜30％、1％＜Ni＜4％、1％＜Co＜3％の範囲を満たすリチウム二次電池用電極を作製することができる。 According to this configuration, the concentration of Fe, Ni, and Co contained in the active material thin film formed on the current collector is 10% <Fe <30%, 1% <Ni <4%, An electrode for a lithium secondary battery that satisfies the range of 1% <Co <3% can be produced.
気相法としては、例えば、PVD（物理的蒸着）法、CVD（化学的蒸着）法が挙げられる。PVD法としては、真空蒸着法、イオンプレーティング法、スパッタ法、レーザーアブレーション法等が挙げられ、CVD法としては、熱CVD法、プラズマCVD法等が挙げられる。中でも真空蒸着法、イオンプレーティング法、スパッタ法が好適に利用できる。気相法を用いることで、集電体との密着性が良好であると共に均質な活物質薄膜を形成することができる。また、薄膜原料を集電体上に成膜する際の雰囲気ガスとしては、ヘリウム（He）、ネオン（Ne）、アルゴン（Ar）といった不活性ガスが好適に利用できる。 Examples of the vapor phase method include a PVD (physical vapor deposition) method and a CVD (chemical vapor deposition) method. Examples of the PVD method include a vacuum deposition method, an ion plating method, a sputtering method, and a laser ablation method. Examples of the CVD method include a thermal CVD method and a plasma CVD method. Of these, vacuum deposition, ion plating, and sputtering can be preferably used. By using the vapor phase method, it is possible to form a uniform active material thin film with good adhesion to the current collector. In addition, as an atmospheric gas for forming the thin film material on the current collector, an inert gas such as helium (He), neon (Ne), or argon (Ar) can be preferably used.
本発明のリチウム二次電池用電極は、Liの吸蔵・放出に伴う活物質薄膜の膨張・収縮程度を緩和して、充放電の際に活物質薄膜が集電体から剥離することを抑制することができる。このようなリチウム二次電池用電極をリチウム二次電池に使用することで、十分な電池容量を有しかつ充放電に伴う電池容量の低下を抑制することができる。また、Liと合金化しない金属にはFeを主に用いており、リチウム二次電池用電極のコストを低く抑えることができる。そして、本発明の製造方法を利用すれば、十分な電池容量を有しかつ充放電に伴う電池容量の低下を抑制することができるリチウム二次電池用電極を作製することができる。 The electrode for a lithium secondary battery of the present invention relaxes the degree of expansion / contraction of the active material thin film that accompanies insertion / extraction of Li, and suppresses the active material thin film from peeling from the current collector during charge / discharge. be able to. By using such an electrode for a lithium secondary battery for a lithium secondary battery, it has sufficient battery capacity and can suppress a decrease in battery capacity due to charge / discharge. Further, Fe is mainly used as a metal that is not alloyed with Li, and the cost of the electrode for the lithium secondary battery can be kept low. And if the manufacturing method of this invention is utilized, the electrode for lithium secondary batteries which has sufficient battery capacity and can suppress the fall of the battery capacity accompanying charging / discharging can be produced.
本発明のリチウム電池用電極の製造方法を用いて、Liと合金化しない金属の種類及び濃度を調整した薄膜原料を集電体上に成膜することで活物質薄膜を形成して、リチウム二次電池用電極を作製した。そして、作製したリチウム二次電池用電極を用いたリチウム二次電池を作製し、電極の性能評価を行った。 Using the method for producing an electrode for a lithium battery of the present invention, an active material thin film is formed on a current collector by depositing a thin film raw material, which is adjusted in the type and concentration of a metal that is not alloyed with Li, to form a lithium secondary battery. A secondary battery electrode was prepared. And the lithium secondary battery using the produced electrode for lithium secondary batteries was produced, and the performance evaluation of the electrode was performed.
＜電極の作製＞
電極は、集電体上に活物質薄膜を形成したものであり、集電体にはCu箔、活物質にはSiを用いた。このCu箔は、厚さ18μmの圧延Cu箔の表面を中心線平均粗さ（Ra）が0.1〜1μm程度になるように電解めっき法により粗面化したものである。また、活物質薄膜は、下記の実施例に示すように、活物質であるSiにLiと合金化しない金属を添加した薄膜原料を集電体上に成膜することで形成した。
<Production of electrode>
The electrode was obtained by forming an active material thin film on a current collector. Cu current was used for the current collector, and Si was used for the active material. This Cu foil is obtained by roughening the surface of a rolled Cu foil having a thickness of 18 μm by electrolytic plating so that the center line average roughness (Ra) is about 0.1 to 1 μm. Moreover, the active material thin film was formed by depositing a thin film material obtained by adding a metal not alloyed with Li to Si as an active material on a current collector, as shown in the following examples.
（実施例１）
Fe-Ni-Co合金（各金属の濃度はFe：54重量％、Ni：30重量％、Co：16重量％）の配合割合が40重量％となるようにSiにこの合金を混合した薄膜原料を用意した。この薄膜原料を真空蒸着法によりCu箔の表面上に堆積させて、Si-Fe-Ni-Co合金からなる薄膜（Si合金薄膜）を形成した。具体的には、真空排気した後にArガスを導入して雰囲気圧力を2×10-3Paとした成膜室内で、電子ビームを照射して薄膜原料を溶融して蒸発させることにより、Cu箔上にSi合金薄膜を形成した。形成するSi合金薄膜の厚さは7μmとし、Si合金薄膜の形成は成膜速度50nm／secで行った。このSi合金薄膜に含有するFe、Ni、Coの濃度は、エネルギー分散型蛍光Ｘ線分析法を用いて測定したところ、それぞれ20重量％、2.1重量％、1.6重量％であった。
Example 1
Thin film raw material in which this alloy is mixed with Si so that the blending ratio of Fe-Ni-Co alloy (concentration of each metal is 54 wt% Fe, 30 wt% Ni, 16 wt% Co) is 40 wt% Prepared. This thin film raw material was deposited on the surface of the Cu foil by a vacuum evaporation method to form a thin film (Si alloy thin film) made of a Si-Fe-Ni-Co alloy. Specifically, the Cu foil was melted and evaporated by irradiating an electron beam in a film forming chamber in which Ar gas was introduced after evacuation and the atmospheric pressure was set to 2 × 10 −3 Pa. A Si alloy thin film was formed on top. The thickness of the Si alloy thin film to be formed was 7 μm, and the Si alloy thin film was formed at a deposition rate of 50 nm / sec. The concentrations of Fe, Ni, and Co contained in the Si alloy thin film were 20 wt%, 2.1 wt%, and 1.6 wt%, respectively, as measured using energy dispersive X-ray fluorescence analysis.
（実施例２）
Fe-Ni-Co合金（各金属の濃度はFe：54重量％、Ni：30重量％、Co：16重量％）の配合割合が30重量％となるようにSiにこの合金を混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Fe-Ni-Co合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するFe、Ni、Coの濃度は、それぞれ13重量％、1.4重量％、1.1重量％であった。
(Example 2)
Thin film raw material in which this alloy is mixed with Si so that the blending ratio of Fe-Ni-Co alloy (concentration of each metal is 54 wt%, Ni: 30 wt%, Co: 16 wt%) is 30 wt% In the same manner as in Example 1, a thin film (Si alloy thin film) made of a Si—Fe—Ni—Co alloy was formed on the surface of the Cu foil. The concentrations of Fe, Ni, and Co contained in the Si alloy thin film were 13% by weight, 1.4% by weight, and 1.1% by weight, respectively.
（比較例１）
Feの配合割合が30重量％となるようにSiにFeを混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Fe合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するFeの濃度は、20重量％であった。
(Comparative Example 1)
A thin film material prepared by mixing Fe with Si so that the Fe content is 30% by weight is prepared, and a thin film made of a Si—Fe alloy on the surface of the Cu foil (Si alloy thin film) in the same manner as in Example 1. Formed. The concentration of Fe contained in this Si alloy thin film was 20% by weight.
（比較例２）
Niの配合割合が20重量％となるようにSiにNiを混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Ni合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するNiの濃度は、2.1重量％であった。
(Comparative Example 2)
A thin film raw material prepared by mixing Ni with Si so that the mixing ratio of Ni is 20% by weight is prepared, and a thin film made of a Si—Ni alloy on the surface of the Cu foil (Si alloy thin film) in the same manner as in Example 1. Formed. The concentration of Ni contained in this Si alloy thin film was 2.1% by weight.
（比較例３）
Coの配合割合が10重量％となるようにSiにCoを混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Co合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するCoの濃度は、1.6重量％であった。
(Comparative Example 3)
A thin film material prepared by mixing Co with Si so that the Co content is 10% by weight is prepared, and a thin film made of a Si—Co alloy on the surface of the Cu foil (Si alloy thin film) in the same manner as in Example 1. Formed. The concentration of Co contained in this Si alloy thin film was 1.6% by weight.
（比較例４）
Fe-Ni-Co合金（各金属の濃度はFe：54重量％、Ni：30重量％、Co：16重量％）の配合割合が50重量％となるようにSiにこの合金を混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Fe-Ni-Co合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するFe、Ni、Coの濃度は、それぞれ33重量％、4.1重量％、3.1重量％であった。
(Comparative Example 4)
Thin film raw material in which this alloy is mixed with Si so that the mixing ratio of Fe-Ni-Co alloy (concentration of each metal is 54% by weight, Ni: 30% by weight, Co: 16% by weight) is 50% by weight. In the same manner as in Example 1, a thin film (Si alloy thin film) made of a Si—Fe—Ni—Co alloy was formed on the surface of the Cu foil. The concentrations of Fe, Ni, and Co contained in the Si alloy thin film were 33% by weight, 4.1% by weight, and 3.1% by weight, respectively.
（比較例５）
Fe-Ni-Co合金（各金属の濃度はFe：54重量％、Ni：30重量％、Co：16重量％）の配合割合が20重量％となるようにSiにこの合金を混合した薄膜原料を用意し、実施例１と同様にして、Cu箔の表面上にSi-Fe-Ni-Co合金からなる薄膜（Si合金薄膜）を形成した。このSi合金薄膜に含有するFe、Ni、Coの濃度は、それぞれ6.7重量％、0.8重量％、0.5重量％であった。
(Comparative Example 5)
Thin film raw material in which this alloy is mixed with Si so that the mixing ratio of Fe-Ni-Co alloy (concentration of each metal is 54% by weight, Ni: 30% by weight, Co: 16% by weight) is 20% by weight. In the same manner as in Example 1, a thin film (Si alloy thin film) made of a Si—Fe—Ni—Co alloy was formed on the surface of the Cu foil. The concentrations of Fe, Ni, and Co contained in the Si alloy thin film were 6.7 wt%, 0.8 wt%, and 0.5 wt%, respectively.
＜電池の作製＞
作製した各電極を負極として用いたコイン型リチウム二次電池をそれぞれ作製した。この電池は、負極、セパレータ、正極の順に積層された積層体を形成して、この積層体をステンレス製のケースに収納した後、有機電解液を封入することで作製した。
<Production of battery>
A coin-type lithium secondary battery using each of the prepared electrodes as a negative electrode was prepared. This battery was fabricated by forming a laminate in which a negative electrode, a separator, and a positive electrode were laminated in this order, housing the laminate in a stainless steel case, and then encapsulating an organic electrolyte.
ここで、リチウム二次電池の正極は、一般的に使用されているLiCoO2を用いて作製した。具体的には、LiCoO2の粉末をAl箔に塗布して作製した。また、リチウム二次電池の有機電解液には、エチレンカーボネートとジエチルカーボネートとの等体積混合溶媒にLiPF6を1モル／リットルの割合で溶解させたものを用いた。セパレータには、ポリプロピレンからなる多孔質材料を用いた。 Here, the positive electrode of the lithium secondary battery was produced using LiCoO 2 which is generally used. Specifically, LiCoO 2 powder was applied to an Al foil. Also, the organic electrolyte of a lithium secondary battery used was LiPF 6 was dissolved at a rate of 1 mole / liter in an equal volume mixed solvent of ethylene carbonate and diethyl carbonate. A porous material made of polypropylene was used for the separator.
そして、このような電池を用いて各電極の性能評価を行った。具体的には、充放電電流を1mA／cm2として、4.2Vまで充電した後、2.75Vまで放電する作業を1サイクルとする充放電サイクル試験を100サイクル行い、各電池の容量維持率を求めた。容量維持率は、次式により求められる。
容量維持率（％）＝（各サイクル時の放電容量／最大放電容量）×100 （式１）
And the performance evaluation of each electrode was performed using such a battery. Specifically, charge / discharge current was set to 1mA / cm 2 and charged to 4.2V, then 100 cycles of charge / discharge cycle test with 1 cycle as the work to discharge to 2.75V, and the capacity maintenance rate of each battery was obtained. It was. The capacity maintenance rate is obtained by the following equation.
Capacity retention rate (%) = (discharge capacity at each cycle / maximum discharge capacity) × 100 (Formula 1)
表１に各電池の100サイクル後の容量維持率を示す。 Table 1 shows the capacity retention rate of each battery after 100 cycles.
表１から明らかなように、本発明のリチウム二次電池用電極である実施例１及び２は、100サイクル後の容量維持率が60％以上であり、比較例１〜５と比較して容量維持率が格段に高い。なお、比較例４の電極は、上記試験条件を満たす充放電を行うことができなかったため、充放電サイクル試験を実施しなかった。これは、Si合金薄膜に含有するSiの濃度が低いことが原因と考えられる。比較例５の電極は、FeといったLiと合金化しない金属の濃度が低く、充放電に伴うSi合金薄膜の膨張・収縮を十分に緩和できないと考えられる。また、Liと合金化しない金属にFeを用いる場合、Si合金薄膜はFeの他にNi、Coを含有していることが好ましく、各金属の濃度が本発明に規定する範囲を満たすことで、充放電に伴うSi合金薄膜の膨張・収縮を効果的に緩和できると考えられる。さらに、実施例１と比較例４との結果から、薄膜原料はFe-Ni-Co合金の配合割合が45重量％未満となるようにすることがより好ましいと推測され、実施例２と比較例５との結果から、薄膜原料はFe-Ni-Co合金の配合割合が25重量％超過となるようにすることがより好ましいと推測される。 As is clear from Table 1, Examples 1 and 2 which are electrodes for lithium secondary batteries of the present invention have a capacity retention rate of 60% or more after 100 cycles, which is higher than that of Comparative Examples 1 to 5. The maintenance rate is much higher. In addition, since the electrode of the comparative example 4 was not able to perform charging / discharging satisfy | filling the said test conditions, the charging / discharging cycle test was not implemented. This is considered due to the low concentration of Si contained in the Si alloy thin film. The electrode of Comparative Example 5 has a low concentration of metal such as Fe that does not alloy with Li, and it is considered that expansion / contraction of the Si alloy thin film accompanying charge / discharge cannot be sufficiently mitigated. Further, when using Fe as a metal that is not alloyed with Li, the Si alloy thin film preferably contains Ni and Co in addition to Fe, and the concentration of each metal satisfies the range defined in the present invention. It is thought that the expansion and contraction of the Si alloy thin film accompanying charging and discharging can be effectively mitigated. Furthermore, from the results of Example 1 and Comparative Example 4, it is presumed that it is more preferable that the thin film raw material has a Fe-Ni-Co alloy content of less than 45 wt%. Example 2 and Comparative Example From the result of 5, it is presumed that the thin film raw material is more preferably such that the blending ratio of the Fe—Ni—Co alloy exceeds 25 wt%.
以上により、本発明のリチウム二次電池用電極を利用することで、充放電に伴う電池容量の低下を抑制することが確認できた。また、本発明の電極は、Liと合金化しない金属にFeを用いた場合であっても、十分な効果を有しており、リチウム二次電池用電極のコストを低く抑えることができる。 From the above, it has been confirmed that the use of the electrode for the lithium secondary battery of the present invention suppresses a decrease in battery capacity caused by charging and discharging. In addition, the electrode of the present invention has a sufficient effect even when Fe is used as a metal that is not alloyed with Li, and the cost of the lithium secondary battery electrode can be kept low.
本発明のリチウム二次電池用電極は、リチウム二次電池に好適に利用することができる。 The electrode for a lithium secondary battery of the present invention can be suitably used for a lithium secondary battery.
Claims (2)
この活物質薄膜はFeの他にNi、Coを含有しており、
この活物質薄膜に含有するFe、Ni、Coの濃度は各々、重量％で10％＜Fe＜30％、1％＜Ni＜4％、1％＜Co＜3％の範囲を満たすことを特徴とするリチウム二次電池用電極。 An electrode for a lithium secondary battery in which an active material thin film containing Fe and an active material that absorbs and releases Li is formed on a current collector,
This active material thin film contains Ni and Co in addition to Fe,
The concentration of Fe, Ni, and Co contained in the active material thin film satisfy the ranges of 10% <Fe <30%, 1% <Ni <4%, and 1% <Co <3%, respectively, by weight. An electrode for a lithium secondary battery.
Ni、Coの濃度が重量％で20％＜Ni＜40％、10％＜Co＜30％の範囲を満たし、残部がFeであるFe-Ni-Co合金を用意する第一工程と、
前記合金の配合割合が重量％で20％＜Fe-Ni-Co合金＜50％となるように、活物質と前記合金とを混合する第二工程と、
前記工程により得られた薄膜原料を気相法により集電体上に成膜することで、活物質薄膜を形成する第三工程とを具えることを特徴とするリチウム二次電池用電極の製造方法。 A method for producing an electrode for a lithium secondary battery that forms an active material thin film containing Fe and an active material that absorbs and releases Li on a current collector,
A first step of preparing an Fe-Ni-Co alloy in which the concentration of Ni and Co satisfies the ranges of 20% <Ni <40% and 10% <Co <30% by weight, and the balance is Fe;
A second step of mixing the active material and the alloy such that the blending ratio of the alloy is 20% by weight% <Fe—Ni—Co alloy <50%;
A third step of forming an active material thin film by depositing a thin film raw material obtained in the above step on a current collector by a vapor phase method, and manufacturing a lithium secondary battery electrode Method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006159099A JP2007329010A (en) | 2006-06-07 | 2006-06-07 | Electrode for lithium secondary battery, and its manufacturing method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006159099A JP2007329010A (en) | 2006-06-07 | 2006-06-07 | Electrode for lithium secondary battery, and its manufacturing method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2007329010A true JP2007329010A (en) | 2007-12-20 |
Family
ID=38929331
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2006159099A Pending JP2007329010A (en) | 2006-06-07 | 2006-06-07 | Electrode for lithium secondary battery, and its manufacturing method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2007329010A (en) |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1125973A (en) * | 1997-07-01 | 1999-01-29 | Matsushita Electric Ind Co Ltd | Negative electrode mateal for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery having negative electrode using the same |
| JP2000133260A (en) * | 1998-10-22 | 2000-05-12 | Matsushita Electric Ind Co Ltd | Nonaqueous electrolyte secondary battery and its manufacture |
| JP2000311681A (en) * | 1998-09-18 | 2000-11-07 | Canon Inc | Negative electrode material for secondary battery, electrode structural body, secondary battery and their manufacture |
| JP2003007291A (en) * | 2001-04-16 | 2003-01-10 | Sanyo Electric Co Ltd | Forming device and forming method of electrode for lithium secondary battery |
| JP2004006206A (en) * | 2001-09-28 | 2004-01-08 | Toshiba Corp | Negative electrode material for nonaqueous electrolyte battery, negative electrode, nonaqueous electrolyte battery, and manufacturing method of negative electrode material |
| JP2004186035A (en) * | 2002-12-04 | 2004-07-02 | Sony Corp | Nonaqueous electrolytic solution battery |
| JP2004319469A (en) * | 2003-04-02 | 2004-11-11 | Matsushita Electric Ind Co Ltd | Negative electrode active substance and nonaqueous electrolyte secondary cell |
| JP2005116264A (en) * | 2003-10-06 | 2005-04-28 | National Institute Of Advanced Industrial & Technology | Manufacturing method of foil strip for lithium ion secondary battery negative electrode by nonaqueous solvent plating |
| WO2005057715A1 (en) * | 2003-12-15 | 2005-06-23 | Nec Corporation | Secondary battery |
| JP2005197080A (en) * | 2004-01-07 | 2005-07-21 | Nec Corp | Anode for secondary battery and secondary battery using it |
-
2006
- 2006-06-07 JP JP2006159099A patent/JP2007329010A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1125973A (en) * | 1997-07-01 | 1999-01-29 | Matsushita Electric Ind Co Ltd | Negative electrode mateal for non-aqueous electrolyte secondary battery and non-aqueous electrolyte secondary battery having negative electrode using the same |
| JP2000311681A (en) * | 1998-09-18 | 2000-11-07 | Canon Inc | Negative electrode material for secondary battery, electrode structural body, secondary battery and their manufacture |
| JP2000133260A (en) * | 1998-10-22 | 2000-05-12 | Matsushita Electric Ind Co Ltd | Nonaqueous electrolyte secondary battery and its manufacture |
| JP2003007291A (en) * | 2001-04-16 | 2003-01-10 | Sanyo Electric Co Ltd | Forming device and forming method of electrode for lithium secondary battery |
| JP2004006206A (en) * | 2001-09-28 | 2004-01-08 | Toshiba Corp | Negative electrode material for nonaqueous electrolyte battery, negative electrode, nonaqueous electrolyte battery, and manufacturing method of negative electrode material |
| JP2004186035A (en) * | 2002-12-04 | 2004-07-02 | Sony Corp | Nonaqueous electrolytic solution battery |
| JP2004319469A (en) * | 2003-04-02 | 2004-11-11 | Matsushita Electric Ind Co Ltd | Negative electrode active substance and nonaqueous electrolyte secondary cell |
| JP2005116264A (en) * | 2003-10-06 | 2005-04-28 | National Institute Of Advanced Industrial & Technology | Manufacturing method of foil strip for lithium ion secondary battery negative electrode by nonaqueous solvent plating |
| WO2005057715A1 (en) * | 2003-12-15 | 2005-06-23 | Nec Corporation | Secondary battery |
| JP2005197080A (en) * | 2004-01-07 | 2005-07-21 | Nec Corp | Anode for secondary battery and secondary battery using it |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3608507B2 (en) | Method for producing alkali metal thin film member | |
| JP3913490B2 (en) | Method for producing electrode for lithium secondary battery | |
| US7122279B2 (en) | Electrode for rechargeable lithium battery and rechargeable lithium battery | |
| US7655354B2 (en) | Battery | |
| US20070092797A1 (en) | Anode, battery, and methods of manufacturing them | |
| WO2010110205A1 (en) | Lithium ion secondary battery, electrode for the battery, and electrodeposited copper foil for the electrode for the battery | |
| WO2001029913A1 (en) | Method for producing material for electrode for lithium cell | |
| JP2002289178A (en) | Lithium secondary battery and electrode for it | |
| JP4497899B2 (en) | Lithium secondary battery | |
| JP2007200862A5 (en) | ||
| JP2002373644A (en) | Electrode for lithium secondary battery, and manufacturing method therefor | |
| JP2006324210A (en) | Negative electrode material for lithium secondary battery and its manufacturing method | |
| US20080026289A1 (en) | Non-aqueous electrolyte secondary battery | |
| JP2008243828A (en) | Negative electrode and manufacturing method for secondary battery | |
| JP2005235397A (en) | Electrode for lithium battery, lithium battery using it, and lithium secondary battery | |
| JP2004139768A (en) | Porous thin film electrode and lithium secondary battery using this as negative electrode | |
| JP2002289177A (en) | Lithium secondary battery and electrode for it | |
| JP2005085632A (en) | Battery | |
| JP2011113735A (en) | Nonaqueous electrolyte battery | |
| JP4329357B2 (en) | Lithium secondary battery negative electrode member and manufacturing method thereof | |
| JP2007123096A (en) | Method of manufacturing electrode for lithium secondary battery | |
| JP2002319432A (en) | Lithium secondary cell | |
| Yang et al. | Lithium-magnesium alloy as an anode for lithium-sulfur based batteries | |
| JP4471603B2 (en) | Lithium secondary battery | |
| JP2007329010A (en) | Electrode for lithium secondary battery, and its manufacturing method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20081222 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20111128 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20120105 |
|
| A02 | Decision of refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A02 Effective date: 20120508 |