JPH103907A - Lithium secondary battery - Google Patents
Lithium secondary batteryInfo
- Publication number
- JPH103907A JPH103907A JP8155115A JP15511596A JPH103907A JP H103907 A JPH103907 A JP H103907A JP 8155115 A JP8155115 A JP 8155115A JP 15511596 A JP15511596 A JP 15511596A JP H103907 A JPH103907 A JP H103907A
- Authority
- JP
- Japan
- Prior art keywords
- negative electrode
- secondary battery
- metal
- lithium secondary
- lithium
- 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.)
- Granted
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
Landscapes
- Carbon And Carbon Compounds (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、リチウム二次電池に係
わるものであって、特に放電容量、出力密度と充放電速
度が大であってサイクル特性に優れたリチウム二次電池
用負極に関する。リチウム二次電池は、電気自動車、メ
モリーバックアップ、ポータブル機器駆動用電源として
利用される。例えば、電子機器に搭載する場合、ノート
パソコン、ワープロ、携帯電話、コードレスフォン子
機、携帯ファックス、携帯プリンター、ヘッドフォンス
テレオ、ビデオムービー、液晶テレビ、ハンディークリ
ーナー、ポータブルCD、電気シェーバー、電子翻訳
機、自動車電話、トランシーバー、電動工具、メモリー
カード等に利用される。その他民生用として医療機器
(ペースメーカー、補聴器、肩もみ機など)、更には宇
宙用或いは太陽電池と組み合わせて利用できる。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithium secondary battery, and more particularly, to a negative electrode for a lithium secondary battery having a large discharge capacity, a high power density and a high charge / discharge rate and excellent cycle characteristics. Lithium secondary batteries are used as power sources for electric vehicles, memory backup, and portable equipment. For example, when installed in electronic devices, notebook computers, word processors, mobile phones, cordless phone handsets, portable faxes, portable printers, headphone stereos, video movies, LCD TVs, handy cleaners, portable CDs, electric shavers, electronic translators, Used for car phones, transceivers, power tools, memory cards, etc. In addition, it can be used in combination with medical equipment (pacemaker, hearing aid, shoulder massager, etc.) for consumer use, or for space use or solar cells.
【0002】[0002]
【従来の技術】リチウム二次電池の負極として、従来は
リチウム (Li) 金属及びLi−Al,Li−Pb等の
合金が用いられてきたが、これらの電池は、樹脂状リチ
ウムの析出による正負極の短絡やサイクル寿命が短く、
エネルギー密度が低いという欠点があった。最近ではこ
れらの問題点を解決するため炭素材を負極に用いる研究
が活発である。この種の負極は、例えば特開平5-299073
号公報、特開平2-121258号公報、特開平6-349482号公
報、特開平7-335623号公報の各公報に開示されている。
特開平5-299073号公報での構成は、芯を形成する高結晶
炭素粒子の表面をVIII族の金属元素を含む膜で被覆し、
さらにその上を炭素が被覆することよりなる炭素複合体
を電極材料としており、これによって表面の乱層構造を
有する炭素材料がリチウムのインターカレーションを助
けると同時に、電極の表面積が大きいために充放電容量
及び充放電速度が著しく向上したとしている。特開平2-
121258号公報では、六方晶でH/C <0.15、面間隔 >3.
37Å及びC軸方向の結晶子の大きさLc <150Åである炭
素物質とLiと合金可能な金属との混合物とすることに
より、充放電サイクル寿命が長く、大電流における充放
電特性も良好であるとしている。特開平6-349482号公報
では、リチウムのインターカレーション・デインターカ
レーション可能な黒鉛粒子全部あるいは一部分の表面上
に酸化銅が付着している炭素複合体を電極材料としてお
り、これによって、酸化銅が電気化学的に還元されたも
のに、可逆的に進行するリチウムと銅の複合酸化物が形
成するため高容量化が可能としている。一方特開平7-33
5263号公報では、負極又は正極活物質に用いる炭素に導
電助剤として金属を添加する事により活物質どうしの接
触抵抗を低下させ、または集電体と活物質間の接触抵抗
を低下させることができ、高率放電(大電流放電)でも
極力容量低下を抑制することができる。負極に限ってい
えば、黒鉛にニッケル、銅、銀、アルミニウム等の金属
担体の他ステンレススチール、パーマロイ等の合金を添
加することにより集電体上の黒鉛の配向を防止できる結
果、黒鉛の端面が電解液側を向いている割合が多くな
り、イオンの拡散が容易になり大電流放電が可能になる
としている。本発明者らは、特願平7-15676号公報にお
いて、炭素粒子の表面にリチウムと合金を形成する金属
の1000Å以下の粒子を担持した炭素粒子を負極材として
用いることにより高容量、出力密度の増大及びサイクル
特性に優れたリチウム二次電池を提供する出願をした。
しかし、いずれにおいても、負極炭素材の調製の難しさ
や炭素の理論容量が引き出されておらず、出力密度が未
だ十分とはいえなかった。特に高速充放電(大電流充放
電)という面では大幅に改善されなければならないとい
う課題があった。したがって、電気自動車、自動二輪車
に搭載するにはエネルギー密度及び出力密度が不十分で
あった。2. Description of the Related Art Conventionally, lithium (Li) metal and alloys such as Li-Al and Li-Pb have been used as a negative electrode of a lithium secondary battery. The short circuit and cycle life of the negative electrode are short,
There was a disadvantage that the energy density was low. Recently, research on using a carbon material for a negative electrode has been actively conducted to solve these problems. This type of negative electrode is disclosed, for example, in Japanese Patent Laid-Open No. 5-299073.
And Japanese Patent Application Laid-Open Nos. Hei 2-121258, Hei 6-349482, and Hei 7-335623.
The configuration in Japanese Patent Application Laid-Open No. 5-299073 discloses that the surface of highly crystalline carbon particles forming a core is coated with a film containing a metal element of Group VIII,
Further, the electrode material is a carbon composite having carbon coated thereon, whereby the carbon material having a turbostratic structure on the surface assists the intercalation of lithium, and at the same time, is filled because the surface area of the electrode is large. It is said that the discharge capacity and the charge / discharge rate have been significantly improved. JP-A-2-
In the publication of 121258, H / C <0.15, interplanar spacing> 3.
By using a mixture of a carbon material having a crystallite size Lc <150 ° in the 37 ° direction and the C-axis direction and a metal alloyable with Li, the charge / discharge cycle life is long and the charge / discharge characteristics at a large current are good. And In JP-A-6-349482, a carbon composite having copper oxide adhered on the surface of all or a part of graphite particles capable of intercalating / deintercalating lithium is used as an electrode material. Since a composite oxide of lithium and copper that progresses reversibly is formed in the electrochemically reduced copper, the capacity can be increased. On the other hand, JP-A-7-33
In Japanese Patent No. 5263, it is possible to reduce the contact resistance between active materials or to reduce the contact resistance between a current collector and an active material by adding a metal as a conductive auxiliary to carbon used for a negative electrode or a positive electrode active material. It is possible to suppress a decrease in capacity as much as possible even at high rate discharge (large current discharge). If it is limited to the negative electrode, the orientation of graphite on the current collector can be prevented by adding alloys such as stainless steel and permalloy to graphite other than metal carriers such as nickel, copper, silver, and aluminum. It is said that the proportion facing the electrolytic solution side is increased, the diffusion of ions is facilitated, and a large current discharge is possible. The present inventors have disclosed in Japanese Patent Application No. 7-15676 a high capacity and a high power density by using carbon particles carrying particles of 1000 mm or less of a metal forming an alloy with lithium on the surface of carbon particles as a negative electrode material. An application has been filed to provide a lithium secondary battery having an excellent increase in cycle and excellent cycle characteristics.
However, in each case, the difficulty in preparing the negative electrode carbon material and the theoretical capacity of carbon were not drawn out, and the output density was not yet sufficient. In particular, there has been a problem that it has to be greatly improved in terms of high-speed charging and discharging (high-current charging and discharging). Therefore, the energy density and the power density were insufficient for mounting on electric vehicles and motorcycles.
【0003】以上のとおり、炭素材及び複合材を負極と
して用いた場合、炭素の理論容量を引き出せないことや
負極炭素材の調製の難しさ、更には高速充放電(大電流
充放電)が出来ないという問題があった。As described above, when a carbon material and a composite material are used as a negative electrode, the theoretical capacity of carbon cannot be drawn out, the preparation of the negative electrode carbon material is difficult, and high-speed charging and discharging (high-current charging and discharging) can be performed. There was no problem.
【0004】[0004]
【発明が解決しようとする課題】本発明らは、前述の問
題点を解決するため鋭意研究をおこない、特定の構成か
らなる負極を用いることにより、高容量、高速充放電が
可能でかつ充放電サイクル特性の優れたリチウム二次電
池を完成し、本発明はこれを提供することを目的とす
る。DISCLOSURE OF THE INVENTION The present inventors have made intensive studies to solve the above-mentioned problems, and by using a negative electrode having a specific structure, high-capacity, high-speed charge / discharge is possible and charge / discharge is possible. It is an object of the present invention to complete a lithium secondary battery having excellent cycle characteristics, and to provide the same.
【0005】[0005]
【課題を解決するための手段】本発明者らは、次のよう
な知見を得て、これに基づき本発明を完成するに至っ
た。まず、従来型負極と改良型負極のサイクル特性の検
討を行い、その測定結果を図1に示す。ここで負極とし
て用いた炭素は、高純度化処理をした天然黒鉛で、その
粒径は約11μmである。この炭素に結着剤としてエチレ
ンプロピレンターポリマー(以下、EPDMと略記す
る)をジエチルベンゼンに溶解した溶液を用い、炭素と
EPDMが94:6の重量比になるようにしたペーストを
集電体である厚さ20μmの銅箔に塗布し、またこれとは
別に該ペーストを集電体である厚さ0.9mm、開孔率93%
の三次元網目構造を有する銅の発泡金属に充填した。こ
こで前者を従来型負極、後者を改良型負極と呼ぶ。両者
を風乾後、80℃で3時間真空乾燥し、0.5ton/cm2の圧
力で成型したのち、さらに150℃で2時間真空乾燥し、
それぞれを負極とした。これら負極の一つを、セパレー
タであるポリプロピレン製微孔膜を間に挟んで、リチウ
ム金属の対極と組合せ、電解液として1MLiPF6/エ
チレンカーボネート−ジメトキシエタン(以下EC−D
MEと略記する)、参照極としてリチウム金属を用いた
試験セルを組立てた。従来型負極、改良型負極について
それぞれ、この試験セルを用いて、充放電速度はカーボ
ン1g当り120mA、充放電の電位幅:0.01〜1.0Vでサイ
クル試験を行った。Means for Solving the Problems The present inventors have obtained the following findings and completed the present invention based on the following findings. First, the cycle characteristics of the conventional negative electrode and the improved negative electrode were examined, and the measurement results are shown in FIG. Here, the carbon used as the negative electrode is natural graphite that has been subjected to a high-purification treatment, and has a particle size of about 11 μm. A paste obtained by dissolving ethylene propylene terpolymer (hereinafter abbreviated as EPDM) in diethylbenzene as a binder in carbon and using carbon and EPDM in a weight ratio of 94: 6 is used as a current collector. The paste is applied to a copper foil with a thickness of 20 μm. Separately, the paste is used as a current collector, with a thickness of 0.9 mm and a porosity of 93%.
Into a copper foam metal having a three-dimensional network structure. Here, the former is called a conventional negative electrode, and the latter is called an improved negative electrode. After air-drying, both were vacuum-dried at 80 ° C. for 3 hours, molded at a pressure of 0.5 ton / cm 2 , and further vacuum-dried at 150 ° C. for 2 hours.
Each was used as a negative electrode. One of these negative electrodes is combined with a lithium metal counter electrode with a polypropylene microporous membrane serving as a separator therebetween, and 1 MLiPF 6 / ethylene carbonate-dimethoxyethane (hereinafter referred to as EC-D) is used as an electrolyte.
A test cell using lithium metal as a reference electrode was assembled. Using this test cell, each of the conventional negative electrode and the improved negative electrode was subjected to a cycle test at a charge / discharge rate of 120 mA / g of carbon and a potential width of charge / discharge: 0.01 to 1.0 V.
【0006】試験の結果は、図1から明らかなように従
来型負極1を用いた場合は、サイクル毎に放電容量は低
下し、約500サイクル後には放電容量は初期容量の約60
%まで低下した。一方、改良型負極2を用いたものは50
0サイクル後においても低下率は4.5%と非常に小さく、
集電体の改良の効果が認められた。この実験事実は、炭
素の粒子間の集電効果が充放電の繰返しによる体積変化
などに起因する電極の膨れのために低下するのを三次元
網目構造を有する改良型電極では抑制できた結果と考え
られる。そこで次に前記の検証をするため以下の実験を
した。すなわち負極合剤中に金属繊維を添加したら同様
の効果が得られるかを検討した。As is clear from FIG. 1, when the conventional negative electrode 1 is used, the discharge capacity decreases every cycle, and after about 500 cycles, the discharge capacity decreases to about 60 times the initial capacity.
%. On the other hand, 50 using the improved negative electrode 2
Even after 0 cycles, the drop rate is as small as 4.5%,
The effect of improving the current collector was recognized. This experimental fact shows that the improved electrode with a three-dimensional network structure was able to suppress the reduction of the current collection effect between carbon particles due to electrode swelling due to volume changes due to repeated charging and discharging. Conceivable. Then, the following experiment was conducted to verify the above. That is, it was examined whether the same effect can be obtained by adding metal fibers to the negative electrode mixture.
【0007】その結果を図2に示す。図2の実験はおお
むね図1と同じであるが、測定条件の概要を以下に示
す。用いた炭素は粒径が約3μmの人造黒鉛で、これに
線径が10μmの銅繊維を90:10の重量比で混合した。こ
の混合物に結着剤としてポリフッ化ビニリデン(以下、
PVDFと略記する)のN−メチルピロリドン溶液を用
い、上記混合物とPVDFを90:10の重量比になるよう
にしたペーストを集電体である厚さ20μmの銅箔に塗
布、風乾後、80℃で3時間真空乾燥し、0.5t/cm2の圧
力で成型したのち、さらに120℃で2時間、真空乾燥
し、負極とした。この負極を、ポリプロピレン製微孔膜
を介在させて、リチウム金属の対極と組合せ、電解液に
1MLiPF6/エチレンカーボネート+ジメトキシカー
ボネート(以下、EC+DMCと略記する)、参照極に
リチウム金属を用いた試験セルを組立てた。充放電速度
は炭素1g当たり120mA、充放電の上下限電位は、それ
ぞれ1.0Vと0.01Vとした。得られた結果を図2に示し
た。ちなみに図2には、銅繊維を添加しない負極の特性
も合わせて示した。図2の結果で明らかなように、銅繊
維を添加しない負極4に対し、銅繊維を添加した負極3
は放電容量が大きくサイクル毎の低下も極端に小さくな
ることが判明した。なお、銅繊維の代りに銅粉末を用い
た負極についても、同様の結果が得られた。以上の結果
から負極合剤層の集電性を高めることは、放電容量やサ
イクル特性の向上に重要な因子であり、炭素と導電性繊
維又は導電性粉末とを単に混合するのではなく、炭素上
にリチウムと合金を形成する金属の微細粒子を担持する
ことにより、炭素・導電性物の混合系に比べて、添加
(担持)量が少なくても同等の効果があると同時に、リ
チウムとの合金化容量が利用できる、又炭素粒子間に金
属を介在させることによる電気導電度や熱伝導度の向上
等が期待できるという新しい機能をもたらすことを見出
し既に出願した。この出願の負極のサイクル試験におい
て、約300サイクルまで安定した性能を示した。FIG. 2 shows the result. The experiment of FIG. 2 is almost the same as that of FIG. 1, but the outline of the measurement conditions is shown below. The carbon used was artificial graphite having a particle size of about 3 μm, and copper fibers having a wire diameter of 10 μm were mixed at a weight ratio of 90:10. Polyvinylidene fluoride (hereinafter, referred to as a binder)
PVDF) (abbreviated as PVDF), a paste obtained by mixing the above mixture and PVDF in a weight ratio of 90:10 was applied to a 20 μm-thick copper foil as a current collector, air-dried, and then dried. After vacuum drying at a temperature of 0.5 ° C. for 3 hours and molding at a pressure of 0.5 t / cm 2 , the product was further vacuum dried at 120 ° C. for 2 hours to obtain a negative electrode. This negative electrode was combined with a lithium metal counter electrode with a polypropylene microporous membrane interposed, and a test using 1 MLiPF 6 / ethylene carbonate + dimethoxycarbonate (hereinafter abbreviated as EC + DMC) as an electrolyte and lithium metal as a reference electrode The cell was assembled. The charge / discharge rate was 120 mA per g of carbon, and the upper and lower limit potentials of the charge / discharge were 1.0 V and 0.01 V, respectively. The results obtained are shown in FIG. FIG. 2 also shows the characteristics of the negative electrode to which no copper fiber was added. As is clear from the results of FIG.
It was found that the discharge capacity was large and the decrease in each cycle was extremely small. Similar results were obtained for a negative electrode using copper powder instead of copper fiber. From the above results, increasing the current collection performance of the negative electrode mixture layer is an important factor for improving the discharge capacity and cycle characteristics.Rather than simply mixing carbon and conductive fibers or conductive powder, carbon is used. By supporting fine particles of a metal that forms an alloy with lithium on top, the same effect can be obtained even if the amount of addition (support) is smaller than that of a mixed system of carbon and conductive materials, It has been found that an alloying capacity can be used, and that a new function can be expected in which electric conductivity and thermal conductivity can be improved by interposing a metal between carbon particles. In the cycle test of the negative electrode of this application, stable performance was shown up to about 300 cycles.
【0008】その後、更なる詳細な検討の結果、負極と
して炭素上にリチウムと合金を形成する金属と合金を形
成しない金属の微細粒子を担持した炭素粒子又は両者の
合金の微細粒子を担持した炭素粒子を用いることによ
り、負極として炭素上にリチウムと合金を形成しない金
属の微細粒子を担持した炭素粒子を用いた場合に比べて
意外にも既出願の前記機能に加えて高速充放電(大電流
充放電)、すなわち電池重量1kg当りのエネルギー密度
350w以上の出力を20分以上放電することを可能にする
ことを見出した。Then, as a result of further detailed examination, it was found that carbon particles carrying fine particles of a metal which forms an alloy with lithium and a metal not forming an alloy on carbon as a negative electrode or carbon particles carrying fine particles of an alloy of both. The use of particles makes it possible to surprisingly add high-speed charge / discharge (high current) in addition to the above-mentioned functions as compared with the case where carbon particles carrying fine particles of a metal that does not form an alloy with lithium on carbon are used as a negative electrode. Charge / discharge), that is, the energy density per kg of battery weight
It has been found that it is possible to discharge an output of 350 w or more for 20 minutes or more.
【0009】すなわち、本発明は、リチウム二次電池を
構成する単電池の負極が、リチウムと合金を形成する金
属と合金を形成しない金属との両者の金属が担持された
炭素粒子又は両者の金属が合金を形成して担持された炭
素粒子を集電体に保持させたものであることを特徴とす
るリチウム二次電池である。上記リチウム二次電池とし
ては、0.5wh〜50kwhの容量を有するものが用いられる。
そして、上記負極を装着するリチウム二次電池は、電池
重量1kg当りのエネルギー密度350w以上の出力を20分
以上放電することを可能にするものである。また、上記
金属は、好ましくは粒径1000Å以下の微細粒子のものが
用いられ、金属の担持量は炭素と金属の全重量に対し30
%以下、好ましくは1〜10wt%以下が良く、Liと合金を
形成する金属と合金を形成しない金属の添加比率は、
1:9〜9:1、好ましくは1:3〜3:1重量比であ
る。That is, according to the present invention, a negative electrode of a unit cell constituting a lithium secondary battery is characterized in that carbon particles carrying both a metal forming an alloy with lithium and a metal not forming an alloy, or a carbon particle carrying both metals. Is a lithium secondary battery characterized in that a carbon particle supported by forming an alloy is held on a current collector. As the lithium secondary battery, one having a capacity of 0.5 wh to 50 kwh is used.
The lithium secondary battery equipped with the above-described negative electrode enables an output having an energy density of 350 W or more per 1 kg of battery weight to be discharged for 20 minutes or more. Further, the metal is preferably used in the form of fine particles having a particle size of 1000 ° or less, and the amount of the metal carried is 30% based on the total weight of carbon and the metal.
% Or less, preferably 1 to 10% by weight or less, and the addition ratio of a metal that forms an alloy with Li and a metal that does not form an alloy is:
The weight ratio is 1: 9 to 9: 1, preferably 1: 3 to 3: 1.
【0010】さらに、本発明は、上記リチウム二次電池
を動力源とするモータを搭載した電気自動車又は自動二
輪車である。そして、このリチウム二次電池は、その充
放電速度が、1C以上で、電池容積1リットル当り350w
h以上のエネルギー密度であるものが用いられる。本発
明で用いる炭素としては、リチウムをインターカレー
ト、デインターカレート可能なもの、例えば天然黒鉛、
石油コークスあるいは石炭ピッチコークス等から得られ
る易黒鉛化材料を2500℃以上の高温で熱処理したもの、
メソフェーズカーボン或いは非晶質炭素及びこれらの混
合物が用いられる。その平均粒径は50μm以下、好まし
くは1〜20μmが好適である。また形状は、球形、塊
状、鱗片状、繊維状あるいはそれらの粉砕品であって良
い。Further, the present invention is an electric vehicle or a motorcycle equipped with a motor powered by the lithium secondary battery. This lithium secondary battery has a charge / discharge rate of 1 C or more and 350 watts per liter of battery capacity.
Those having an energy density of h or more are used. As carbon used in the present invention, those capable of intercalating and deintercalating lithium, for example, natural graphite,
Graphitizable material obtained from petroleum coke or coal pitch coke, etc. heat-treated at a high temperature of 2500 ° C or higher,
Mesophase carbon or amorphous carbon and mixtures thereof are used. The average particle size is 50 μm or less, preferably 1 to 20 μm. The shape may be spherical, massive, scale-like, fibrous, or a crushed product thereof.
【0011】リチウムと合金を形成する担持金属として
は、Al,Sb,B,Ba,Bi,Cd,Ca,Ga,
In,Ir,Pb,Hg,Si,Ag,Sr,Te,T
i及びSnのうち少なくとも1種類が選択されるが、好
ましくは(1)リチウム含有量が多い合金組成、(2)
原子量が比較的小さく、密度が比較的大きい、(3)還
元が容易、(4)リチウム合金の酸化還元電位が低い、
(5)廃棄上の問題が少ない、(6)比較的安価であ
る、等の諸条件を満たすものがよい。The supported metals forming an alloy with lithium include Al, Sb, B, Ba, Bi, Cd, Ca, Ga,
In, Ir, Pb, Hg, Si, Ag, Sr, Te, T
At least one of i and Sn is selected, but preferably (1) an alloy composition having a high lithium content, (2)
Relatively low atomic weight, relatively high density, (3) easy reduction, (4) low oxidation-reduction potential of lithium alloy,
It is preferable to satisfy various conditions such as (5) there is little problem in disposal, and (6) it is relatively inexpensive.
【0012】次にリチウムと合金を形成しない金属とし
ては、Fe,Ni,Cu,Pt及びAuのうち少なくと
も1種類が選択されるが、好ましくは(1)酸化電位が
高い、(2)還元が容易、(3)廃棄上の問題が少な
い、(4)比較的安価である、等の諸条件を満たすもの
がよい。金属の担持方法としては、蒸着法、スパッタリ
ング法、湿式還元法、電気化学的還元法、メッキ法及び
気相還元ガス処理法等の方法があるが、用いる金属種に
対応して最適な担持法を適用すればよい。また金属の担
持量としては、両者の合計量として30wt%以下、好まし
くは1〜10wt%が好適である。リチウムと合金を形成す
る金属とリチウムと合金を形成しない金属の添加比率
は、1:9〜9:1、好ましくは1:3〜3:1であ
る。そして、両者の金属の添加比率が前記範囲でない場
合、高速充放電(大電流充放電)の効果が得られない。Next, at least one of Fe, Ni, Cu, Pt and Au is selected as a metal which does not form an alloy with lithium. Preferably, (1) the oxidation potential is high, and (2) reduction is It is preferable to satisfy various conditions such as easy, (3) little problem in disposal, and (4) relatively low cost. Metal loading methods include vapor deposition, sputtering, wet reduction, electrochemical reduction, plating, and gas-phase reduction gas treatment, but the most suitable loading method is selected according to the type of metal used. Should be applied. The amount of metal carried is preferably 30 wt% or less, preferably 1 to 10 wt%, as the total amount of both. The addition ratio of the metal that forms an alloy with lithium and the metal that does not form an alloy with lithium is 1: 9 to 9: 1, preferably 1: 3 to 3: 1. If the addition ratio of the two metals is not in the above range, the effect of high-speed charge / discharge (high-current charge / discharge) cannot be obtained.
【0013】リチウムと合金を形成する金属と合金を形
成しない金属について、合金を形成させるには、例えば
湿式還元でCuとSnを炭素粒子上に担持し、乾燥した
炭素粉を還元ガス気流中にて所定の温度で熱処理するこ
とによって行われる。更に担持された金属の粒径は、合
金で形成する金属の場合充放電におけるリチウム合金の
析出・溶解速度を考慮し、又合金を形成しない金属の場
合、電子電導性を左右する炭素間の接触点を増大させる
ため1000Å以下が望ましい。更に、担持された金属の粒
径は合金を形成する金属の場合、充放電におけるリチウ
ム金属の析出、溶解速度を考慮し、又合金を形成しない
金属の場合、電子電導性を左右する炭素間の接触点を増
大させるため1000Å以下が望ましい。In order to form an alloy with a metal which forms an alloy with lithium and a metal which does not form an alloy, for example, Cu and Sn are supported on carbon particles by wet reduction, and dried carbon powder is placed in a reducing gas stream. The heat treatment is performed at a predetermined temperature. Furthermore, the particle size of the supported metal is determined by considering the precipitation and dissolution rate of the lithium alloy during charge and discharge in the case of a metal formed of an alloy. 1000 mm or less is desirable to increase points. Furthermore, the particle size of the supported metal is determined by considering the precipitation and dissolution rate of lithium metal during charge and discharge in the case of a metal that forms an alloy, and in the case of a metal that does not form an alloy, between carbons that affect electron conductivity. 1000 mm or less is desirable to increase the contact point.
【0014】以上で得られた金属担持炭素粒子を用いて
負極を作成するが、この場合に結着剤を用いる。結着剤
としては、例えばEPDM、PVDF、ポリテトラフル
オロエチレン等電解液と反応しないものであれば、特に
限定されない。結着剤の配合量は、カーボンに対し1〜
30wt%、好ましくは、5〜15wt%が好適である。前述の
合剤を用いた負極形状としては、シート状、フィルム
状、金属箔上にフィルム状或いは発泡金属に充填するな
どして電池形状に適応させる事が可能である(図4参
照)。合剤層厚みは、10〜200μmの範囲が望ましい。A negative electrode is prepared using the metal-supported carbon particles obtained as described above. In this case, a binder is used. The binder is not particularly limited as long as it does not react with an electrolytic solution such as EPDM, PVDF, and polytetrafluoroethylene. The amount of the binder is 1 to carbon.
30 wt%, preferably 5 to 15 wt% is suitable. The shape of the negative electrode using the above-mentioned mixture can be adapted to the shape of a battery by, for example, filling a film or foam metal on a sheet, film, or metal foil (see FIG. 4). The thickness of the mixture layer is preferably in the range of 10 to 200 μm.
【0015】このようにして得られた負極は、通常用い
られる正極、セパレータおよび電解液と組合わせること
により最適なリチウム二次電池とすることが出来る。正
極に用いる活物質としては、LiCoO2,LiNiO2やLiMn2O4
等のリチウムを含有した複合酸化物が用いられてよく、
これに導電剤のカーボンブラックや炭素および粘着剤を
混合したものをAl箔等の集電体に塗布して正極とす
る。By combining the negative electrode thus obtained with a commonly used positive electrode, a separator and an electrolytic solution, an optimal lithium secondary battery can be obtained. The active materials used for the positive electrode include LiCoO 2 , LiNiO 2 and LiMn 2 O 4
A composite oxide containing lithium such as may be used,
A mixture of a conductive agent such as carbon black or carbon and an adhesive is applied to a current collector such as an Al foil to form a positive electrode.
【0016】セパレータとしては、ポリプロピレン、ポ
リエチレンやポリオレフィン系の多孔質膜が用いられて
いる。また電解液としては、プロピレンカーボネート
(PC)、エチレンカーボネート(EC)、1,2−ジ
メトキシエタン(DME)、ジメトキシカーボネート
(DMC)、ジエチルカーボネート(DEC)、メチル
エチルカーボネート(MEC)などの2種類以上の混合
溶媒が用いられる。また電解質としては、LiPF6,LiB
F4,LiClO4等があり、上記溶媒に溶解したものが用いら
れる。As the separator, a porous film of polypropylene, polyethylene or polyolefin is used. As the electrolytic solution, two types such as propylene carbonate (PC), ethylene carbonate (EC), 1,2-dimethoxyethane (DME), dimethoxycarbonate (DMC), diethyl carbonate (DEC), and methyl ethyl carbonate (MEC) are used. The above mixed solvents are used. LiPF 6 , LiB
There are F 4 , LiClO 4 and the like, and those dissolved in the above-mentioned solvents are used.
【0017】リチウム二次電池用炭素負極を改良し、て
リチウムと合金を形成する金属と合金を形成しない金属
の微細粒子を担持した炭素粒子又は両者の合金の微細粒
子を担持した炭素粒子を用いることにより、(1)放電
容量の増大する、(2)出力密度の向上する、(3)電
気伝導性が向上し、充放電反応の速度が向上する、
(4)添加金属がリチウムと形成する合金の充放電容量
が利用できるので黒鉛の理論容量の372mAh/gを越える
値が得られる、(5)不可逆容量を引き起こす炭素粒子
表面の反応サイトを担持金属が覆うので不可逆容量が低
減される、(6)放電容量が大きくなるので電池の出力
密度も当然大きくなる、(7)前記(2)に付随してサ
イクル特性も向上し、組電池における熱放散性も向上さ
せることができる、等の顕著な効果がえられる。An improved carbon negative electrode for a lithium secondary battery uses carbon particles carrying fine particles of a metal that forms an alloy with lithium and a metal that does not form an alloy or carbon particles carrying fine particles of an alloy of both. Thereby, (1) the discharge capacity is increased, (2) the output density is improved, (3) the electric conductivity is improved, and the speed of the charge / discharge reaction is improved.
(4) Since the charge / discharge capacity of an alloy formed with lithium as an additional metal can be used, a value exceeding the theoretical capacity of graphite of 372 mAh / g can be obtained. (5) The metal supporting the reaction site on the carbon particle surface causing the irreversible capacity (6) Naturally, the output density of the battery is also increased because the discharge capacity is increased. (7) The cycle characteristics are improved accompanying the above (2), and the heat dissipation in the assembled battery is improved. A remarkable effect is obtained such that the property can be improved.
【0018】[0018]
【発明の実施の形態】以下に本発明を実施例により具体
的に説明する。ただし、本発明の技術的範囲がこれら実
施例に限定されるものではない。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to examples. However, the technical scope of the present invention is not limited to these examples.
【0019】[0019]
[実施例1]高純度化処理した人造黒鉛(面間隔d002
=3.359Å、結晶子大きさLc =540Å、比表面積=10m2/
g)9.5gを25mlのエタノールを含む水450mlに懸濁させ
る。これを約55℃に加温し、強攪拌しながら0.39gの硝
酸銀(AgNO3)と0.95gの硝酸銅(Cu(NO3)2・3H2O)を添加
し溶解させる。これに8mlのヒドラジン(N2H4) を含む
水100ml をマイクロチューブポンプで滴下し、約3時間
かけて同時還元反応を完結させる。その後、ロ過・水洗
して、350℃で6時間真空乾燥した。得られた粉末A中
の金属量は、化学分析によれば、仕込み重組織の各々2.
5重量%に対し、Agは2.45重量%、Cuは2.32重量%
であった。また、X線回折によりAgとCuの存在状態
を調べたところ、金属状態のAgとCuの回折線に加え
て酸化第1銅:Cu2O に基づく極く微量の回折線が認め
られた。次にエネルギー分散型電子プローブマイクロア
ナリシスにより、AgとCuの分散状態を観察したとこ
ろ、Ag及びCu粒子は黒鉛粒子の全面に分布してお
り、黒鉛粒子の端面部に若干濃縮していた。さらに透過
型電子顕微鏡で金属粒子の大きさを観察したところ、数
百Åの粒子がほぼ均一に分散していた。[Example 1] Artificial graphite subjected to high purification treatment (interplanar spacing d 002)
= 3.359 °, crystallite size Lc = 540 °, specific surface area = 10m 2 /
g) Suspend 9.5 g in 450 ml of water containing 25 ml of ethanol. This was heated to about 55 ° C., and 0.39 g of silver nitrate (AgNO 3 ) and 0.95 g of copper nitrate (Cu (NO 3 ) 2 .3H 2 O) were added and dissolved with vigorous stirring. To this, 100 ml of water containing 8 ml of hydrazine (N 2 H 4 ) is dropped by a microtube pump, and the simultaneous reduction reaction is completed in about 3 hours. Thereafter, the mixture was filtered and washed with water, and vacuum dried at 350 ° C. for 6 hours. According to chemical analysis, the amount of metal in the obtained powder A was 2.
Ag is 2.45% by weight and Cu is 2.32% by weight with respect to 5% by weight.
Met. Further, when the existence states of Ag and Cu were examined by X-ray diffraction, a very small amount of diffraction lines based on cuprous oxide: Cu 2 O were recognized in addition to the diffraction lines of Ag and Cu in a metal state. Next, when the dispersion state of Ag and Cu was observed by an energy dispersive electron probe microanalysis, the Ag and Cu particles were distributed over the entire surface of the graphite particles, and were slightly concentrated on the end surfaces of the graphite particles. Further, when the size of the metal particles was observed with a transmission electron microscope, several hundreds of particles were almost uniformly dispersed.
【0020】[実施例2]高純度化処理を行った天然黒
鉛(d002 =3.362Å、Lc =330Å、比表面積=20m2/
g)を用いて実施例1と同様の操作を行い粉末Bを得
た。 [実施例3]高純度化処理を行った人造黒鉛9.5gを25m
lのエタノールを含む水450mlに懸濁させる。これを約55
℃に加温し、強攪拌しながら0.39gとAgNO3と1.24gの
硝酸ニッケル(Ni(NO3)2・6H2O)を添加し溶解させる。
これに0.5重量%のテトラヒドリドホウ酸ナトリウム(N
aBH4) 水溶液をマイクロチューブポンプで滴下し、約3
時間かけて同時還元反応を完結させる。その後、ロ過、
水洗して350℃で6時間真空乾燥した。得られた粉末C
中の金属量は、化学分析によれば、仕込み量組成の各々
2.5重量%に対し、Agは2.44重量%、Niは2.30重量
%であった。また、X線回折によりAgとNiの存在状
態を調べたところ、金属状態のAgとNiの回折線に加
えてNiOに基づく極く微量の回折線が認められた。次
にエネルギー分散型電子プローブマイクロアナリシスに
より、AgとNiの分散状態を観察したところ、Ag及
びNiは黒鉛粒子の全面に分布しており、黒鉛粒子の端
面部に若干濃縮していた。さらに濾過型電子顕微鏡で金
属粒子の大きさを観察したところ、数百Åの粒子がほぼ
均一に分散していた。Example 2 Highly purified natural graphite (d 002 = 3.362 °, Lc = 330 °, specific surface area = 20 m 2 /
The same operation as in Example 1 was performed using g) to obtain Powder B. [Example 3] 9.5 g of artificial graphite subjected to a high-purification treatment was applied to 25 m
Suspend in 450 ml of water containing l ethanol. About 55
The mixture was heated to ℃ and 0.39 g, AgNO 3 and 1.24 g of nickel nitrate (Ni (NO 3 ) 2 .6H 2 O) were added and dissolved with vigorous stirring.
0.5% by weight of sodium tetraborohydride (N
aBH 4 ) Drop the aqueous solution with a micro tube pump,
Complete the simultaneous reduction reaction over time. After that,
It was washed with water and vacuum dried at 350 ° C. for 6 hours. Powder C obtained
According to chemical analysis, the amount of metal in each
Ag was 2.44% by weight and Ni was 2.30% by weight with respect to 2.5% by weight. In addition, when the existence state of Ag and Ni was examined by X-ray diffraction, a very small amount of diffraction line based on NiO was recognized in addition to the diffraction lines of Ag and Ni in a metal state. Next, when the dispersion state of Ag and Ni was observed by an energy dispersive electron probe microanalysis, Ag and Ni were distributed over the entire surface of the graphite particles, and were slightly concentrated on the end surfaces of the graphite particles. Further, when the size of the metal particles was observed with a filtration electron microscope, several hundreds of particles were almost uniformly dispersed.
【0021】[実施例4]高純度化処理を行った天然黒
鉛を用いて実施例3と同様の操作を行い粉末Dを得た。 [実施例5]エタノール25mlと水450mlを混合し、55℃
に加温する。これに0.5gのフタル酸水素カリウムを添
加溶解した後、強攪拌しながら0.39gとAgNO3とCu(NO3)
2 ・3H2O 0.95gを添加し溶解する。次いでこれに高純
度化処理した人造黒鉛9.5gを加え懸濁させる。この懸
濁液を強攪拌しながら0.5重量%のNaBH4水溶液をマイク
ロチューブポンプで滴下し、約3時間かけて同時還元反
応を完結させる。その後、ロ過、水洗して350℃で6時
間真空乾燥した。得られた粉末Eは、実施例1の粉末A
とほとんど同じものが得られたが、炭素上の金属粒子の
粒径は、粉末Aのものより小さく、分散状態が改良され
ていた。Example 4 The same operation as in Example 3 was performed using natural graphite that had been subjected to a high-purification treatment to obtain powder D. Example 5 A mixture of 25 ml of ethanol and 450 ml of water was mixed at 55 ° C.
Warm up. After adding and dissolving 0.5 g of potassium hydrogen phthalate thereto, 0.39 g of AgNO 3 and Cu (NO 3 ) were stirred with vigorous stirring.
It was added 2 · 3H 2 O 0.95g dissolved. Next, 9.5 g of highly purified artificial graphite is added and suspended. A 0.5% by weight aqueous solution of NaBH 4 is dropped with a microtube pump while vigorously stirring this suspension, and the simultaneous reduction reaction is completed over about 3 hours. Thereafter, the mixture was filtered, washed with water, and vacuum dried at 350 ° C. for 6 hours. The powder E obtained was the powder A of Example 1.
However, the particle size of the metal particles on carbon was smaller than that of the powder A, and the dispersion state was improved.
【0022】[実施例6]2ml酢酸−25mlエタノール−
25mlH2Oの混合溶液に0.475gSnCl2・2H2Oと0.95gCu(NO
3)2・3H2Oを溶解した後、蒸留水を加え400mlとする。こ
の溶液に9.5gの高純度化処理した人造黒鉛を懸濁させ
約50℃に加温する。次いで懸濁液を強く攪拌しながら水
100ml に1.7gのNaBH4を含む還元剤液を滴下して還元反
応を行わしめる。その後、濾過水洗して150℃で20時間
真空乾燥して粉末Fを得た。粉末のX線回析において
は、黒鉛に基づく回析線の他に金属状態のCuとSnの
回析線と微量の酸化第一銅の回析線が認められた。Example 6 2 ml acetic acid-25 ml ethanol
In a mixed solution of 25mlH 2 O 0.475gSnCl 2 · 2H 2 O and 0.95gCu (NO
3) was dissolved 2 · 3H 2 O, distilled water was added to 400 ml. 9.5 g of highly purified artificial graphite is suspended in this solution and heated to about 50 ° C. The suspension is then stirred vigorously with water.
A reducing agent solution containing 1.7 g of NaBH 4 is dropped into 100 ml to carry out a reduction reaction. Thereafter, the resultant was washed with filtered water and vacuum-dried at 150 ° C. for 20 hours to obtain a powder F. In the X-ray diffraction of the powder, in addition to a diffraction line based on graphite, a diffraction line of Cu and Sn in a metal state and a diffraction line of a trace amount of cuprous oxide were recognized.
【0023】[比較例1]実施例5の操作において、0.
98gのAgNO3のみを添加し、全く同じ条件で5重量%A
g/人造黒鉛の粉末Gを得た。 [比較例2]実施例5の操作において、0.95gのCu(N
O3)2・3H2Oのみを添加し、全く同じ条件で2.5重量%C
u/人造黒鉛の粉末Hを得た。[Comparative Example 1]
Only 98 g of AgNO 3 was added and 5 wt% A
g / artificial graphite powder G was obtained. Comparative Example 2 In the operation of Example 5, 0.95 g of Cu (N
O 3) 2 · 3H 2 O alone were added, 2.5 weight% C under the same conditions
u / artificial graphite powder H was obtained.
【0024】[実施例7]上記実施例1〜6と比較例1
及び2で得られた粉末A〜Hに結着剤としてPVDFの
N−メチルピロリドン溶液を用い、各粉末とPVDFを
90:10の重量比になるようにしたペーストを集電体であ
る厚さ20μmの銅箔に塗布、風乾後、80℃で3時間真空
乾燥し、0.5ton/cm2の圧力で成型したのち、さらに120
℃で2時間、真空乾燥し、負極A〜Hを得た。又高純度
化処理を行った人造黒鉛のみを用いて上述の操作で負極
Iを得た。これらの負極をポリエステル製の多孔質膜を
介してリチウム金属の対極と組合せ、電解液に1MLi
PF6/EC+DMC、参照極にリチウム金属を用いた
試験セルを組立てた。充放電速度は炭素1g当たり120m
A、充放電の上下限電位は、それぞれ1.0Vと0.01Vとし
た。得られた結果を放電容量〔mAh/g・(炭素+金
属)〕として表1にまとめて示した。Example 7 The above Examples 1 to 6 and Comparative Example 1
The powders A to H obtained in the above steps 2 and 3 were mixed with a N-methylpyrrolidone solution of PVDF as a binder.
A paste having a weight ratio of 90:10 was applied to a copper foil having a thickness of 20 μm as a current collector, air-dried, vacuum-dried at 80 ° C. for 3 hours, and molded at a pressure of 0.5 ton / cm 2. And 120 more
It vacuum-dried at 2 degreeC for 2 hours, and obtained the negative electrodes AH. Further, the negative electrode I was obtained by the above-mentioned operation using only the artificial graphite subjected to the high-purification treatment. These negative electrodes were combined with a lithium metal counter electrode through a polyester porous membrane, and 1 M Li
A test cell using PF 6 / EC + DMC and lithium metal for the reference electrode was assembled. Charge / discharge speed is 120m / g carbon
A, the upper and lower limit potentials of charge and discharge were set to 1.0 V and 0.01 V, respectively. The obtained results are summarized in Table 1 as discharge capacity [mAh / g · (carbon + metal)].
【0025】[0025]
【表1】 [Table 1]
【0026】又負極I,G,F,Eについて充放電速度
を変えたときの放電容量を測定し、その結果を図3に示
した。図より明らかなごとく本発明による負極Eは、充
放電速度が高い場合においても放電容量の大きいことが
わかる。ちなみに250mAh/gの放電容量を維持するため
には人造黒鉛のみの負極を1.0とすると5重量%Ag担
持人造黒鉛負極は約1.7、2.5重量%Cu担持人造黒鉛負
極は約1.6、2.5重量%Ag−2.5重量%Cu担持人造黒
鉛は、約3.2倍となり、高速充放電(大電流充放電)に
耐える負極材料であることが判明した。又負極A,B,
C,D,Fについても同様の試験を行った結果、負極E
とほぼ同等の結果が得られた。The discharge capacities of the negative electrodes I, G, F and E were measured when the charge / discharge rate was changed, and the results are shown in FIG. As is apparent from the figure, the negative electrode E according to the present invention has a large discharge capacity even when the charge / discharge rate is high. Incidentally, in order to maintain a discharge capacity of 250 mAh / g, when the negative electrode made of artificial graphite alone is assumed to be 1.0, the artificial graphite negative electrode carrying 5 wt% Ag is about 1.7, and the artificial graphite negative electrode carrying 2.5 wt% Cu is about 1.6, 2.5 wt% Ag. The artificial graphite loaded with -2.5% by weight of Cu was about 3.2 times, and was found to be a negative electrode material that could withstand high-speed charge / discharge (high-current charge / discharge). The negative electrodes A, B,
The same test was performed for C, D, and F.
Almost the same result was obtained.
【0027】〔実施例8〕実施例6で得られた粉末Fを
4%H2/He気流中、550℃−3時間熱処理した。この
粉末のX線分析によりCuとSnの金属に基づく回析線
以外に合金化に基づく回析線が認められた。この粉末を
用いて実施例7と同様、負極の評価を行った。放電容量
は、粉末Fを用いた負極とほぼ同じ値であった。Example 8 The powder F obtained in Example 6 was heat-treated at 550 ° C. for 3 hours in a 4% H 2 / He gas stream. X-ray analysis of this powder showed diffraction lines based on alloying in addition to diffraction lines based on Cu and Sn metals. The negative electrode was evaluated in the same manner as in Example 7 using this powder. The discharge capacity was almost the same value as the negative electrode using powder F.
【0028】〔実施例9〕実施例1の操作において、C
u:Agの重量比が3:1になるように仕込み、同じ操
作で粉末を得た。この粉末を用いて実施例7と同様、負
極の評価を行った。放電容量は、粉末Aを用いた負極と
ほぼ同等の値を示した。 〔実施例10〕実施例1の操作において、Cu:Agの
重量比が1:3になるように仕込み、同じ操作で粉末を
得た。この粉末を用いて実施例7と同様、負極の評価を
行った。放電容量は、粉末Aを用いた負極とほぼ同等の
値を示した。Embodiment 9 In the operation of Embodiment 1, C
The powders were charged so that the weight ratio of u: Ag was 3: 1 and the powder was obtained by the same operation. The negative electrode was evaluated in the same manner as in Example 7 using this powder. The discharge capacity showed a value almost equivalent to that of the negative electrode using powder A. Example 10 The procedure of Example 1 was repeated except that the weight ratio of Cu: Ag was 1: 3, and a powder was obtained by the same operation. The negative electrode was evaluated in the same manner as in Example 7 using this powder. The discharge capacity showed a value almost equivalent to that of the negative electrode using powder A.
【0029】〔実施例11〕実施例1の操作において、
Cu:Agの重量比が9:1になるように仕込み、同じ
操作で粉末を得た。この粉末を用いて実施例7と同様、
負極の評価を行った。放電容量は、粉末Aを用いた負極
の370mAh/gの値に対し350mAh/gであった。[Embodiment 11] In the operation of Embodiment 1,
Cu: Ag was added so as to have a weight ratio of 9: 1, and a powder was obtained by the same operation. Using this powder, as in Example 7,
The negative electrode was evaluated. The discharge capacity was 350 mAh / g with respect to the value of 370 mAh / g of the negative electrode using powder A.
【0030】〔実施例12〕実施例1の操作において、
Cu:Agの重量比が1:9になるように仕込み、同じ
操作で粉末を得た。この粉末を用いて実施例7と同様、
負極の評価を行った。放電容量は、360mAh/gの値を示
した。 〔実施例13〕実施例1の操作において、人造黒鉛の20
重量部をX線分析のdooz面から求めた面間隔3.85Å
の非晶質で置きかえた粉末を得た。この粉末を用いて実
施例7と同様、負極の評価を行った。放電容量は、粉末
Aを用いた負極とほぼ同等の値であった。Example 12 In the operation of Example 1,
The powders were charged so that the weight ratio of Cu: Ag was 1: 9, and a powder was obtained by the same operation. Using this powder, as in Example 7,
The negative electrode was evaluated. The discharge capacity showed a value of 360 mAh / g. [Example 13] In the operation of Example 1, 20% of artificial graphite was used.
3.85 ° spacing between parts by weight obtained from the dooz surface of X-ray analysis
Powder was obtained which was replaced by amorphous. The negative electrode was evaluated in the same manner as in Example 7 using this powder. The discharge capacity was almost the same as that of the negative electrode using powder A.
【0031】[実施例14]厚さ20μmのアルミ箔に、
LiCoO2 活物質と人造黒鉛とPVDFを重量比で87:
9:4とした合剤を両面に塗布し乾燥・圧延し片面90μ
m厚さとなるようにした正極15と、厚さ20μmの銅箔に
実施例5で得られた粉末EをPVDFと重量比で9:1
となるようにした合剤を両面に塗布し乾燥・圧延し片面
58μm厚さとなるようにした負極17及び厚さ25μmのポ
リエチレン製多孔質膜セパレータ19を、図4に示すよう
に捲回して外寸法14φ−47mmの電池缶に収納し、電解液
として1MLiPF6 /EC−DMCを用いて、その特
性を評価した。Example 14 On an aluminum foil having a thickness of 20 μm,
LiCoO 2 active material, artificial graphite and PVDF in a weight ratio of 87:
9: 4 mixture was applied on both sides, dried and rolled, and 90μ on one side
The powder E obtained in Example 5 was applied to a positive electrode 15 having a thickness of 20 m and a copper foil having a thickness of 20 μm by weight ratio of PVDF to PVDF of 9: 1.
Is applied to both sides, dried and rolled to make one side
A negative electrode 17 having a thickness of 58 μm and a porous membrane separator 19 made of polyethylene having a thickness of 25 μm were wound as shown in FIG. 4 and housed in a battery can having an outer dimension of 14φ−47 mm, and 1 MLiPF 6 / The characteristics were evaluated using EC-DMC.
【0032】試験条件として、充放電速度:1C、充電
終止電圧4.2V、放電終止電圧2.5Vとして行った。その
結果、350wh/l のエネルギー密度が得られ、300サイク
ルまで安定した性能を示している。The test conditions were as follows: charge / discharge rate: 1 C, charge end voltage 4.2 V, discharge end voltage 2.5 V. As a result, an energy density of 350 wh / l was obtained, and stable performance was shown up to 300 cycles.
【0033】[0033]
【発明の効果】リチウム二次電池において、新規な負極
を用いることにより特に放電容量、出力密度と充放電速
度が大であってサイクル特性に優れたリチウム二次電池
を提供することができる。このリチウム二次電池は、電
気自動車、メモリーバックアップ、ポータブル機器駆動
用電源として利用される。As described above, by using a novel negative electrode in a lithium secondary battery, it is possible to provide a lithium secondary battery having particularly high discharge capacity, output density and charge / discharge rate and excellent cycle characteristics. This lithium secondary battery is used as a power source for driving electric vehicles, memory backups, and portable devices.
【図1】従来型負極と改良型負極のサイクル特性図。FIG. 1 is a cycle characteristic diagram of a conventional negative electrode and an improved negative electrode.
【図2】銅繊維添加負極と無添加負極のサイクル特性
図。FIG. 2 is a cycle characteristic diagram of a copper fiber-added negative electrode and a non-added negative electrode.
【図3】本発明よりなる負極と従来・改良型の負極の充
放電速度と放電容量の関係を示す図。FIG. 3 is a diagram showing the relationship between the charge / discharge rate and discharge capacity of a negative electrode according to the present invention and a conventional / improved negative electrode.
【図4】本発明の円筒形電池の構成図。FIG. 4 is a configuration diagram of a cylindrical battery of the present invention.
1…従来型負極のサイクル特性、2…改良型負極のサイ
クル特性、3…銅繊維添加負極のサイクル特性、4…無
添加負極のサイクル特性、5…本発明負極の充放電速度
と放電容量の関係、6…Ag担持人造黒鉛粉末を用いた
負極の充放電速度と放電容量の関係、7…Cu担持人造
黒鉛粉末を用いた負極の充放電速度と放電容量の関係、
8…人造黒鉛粉末を用いた負極の充放電速度と放電容量
の関係、15…正極、16…正極端子、17…負極、18…負極
端子、19…セパレータ1: Cycle characteristics of conventional negative electrode, 2: Cycle characteristics of improved negative electrode, 3: Cycle characteristics of copper fiber-added negative electrode, 4: Cycle characteristics of non-added negative electrode, 5: Charge-discharge rate and discharge capacity of negative electrode of the present invention Relationship 6: Relationship between charge / discharge speed and discharge capacity of negative electrode using Ag-supported artificial graphite powder, 7 Relationship between charge / discharge speed and discharge capacity of negative electrode using Cu-supported artificial graphite powder,
8 Relationship between charge / discharge rate and discharge capacity of negative electrode using artificial graphite powder, 15 positive electrode, 16 positive electrode terminal, 17 negative electrode, 18 negative electrode terminal, 19 separator
Claims (8)
極が、リチウムと合金を形成する金属と合金を形成しな
い金属との両者の金属が担持された炭素粒子又は両者の
金属が合金を形成して担持された炭素粒子を集電体に保
持させたものであることを特徴とするリチウム二次電
池。1. A negative electrode of a unit cell constituting a lithium secondary battery is characterized in that carbon particles carrying both a metal forming an alloy with lithium and a metal not forming an alloy or a metal forming an alloy with both metals A lithium secondary battery characterized in that the carbon particles supported as described above are held by a current collector.
〜50kwhの容量を有するものであることを特徴とする請
求項1記載のリチウム二次電池。2. The lithium secondary battery used is 0.5 wh.
2. The lithium secondary battery according to claim 1, wherein the lithium secondary battery has a capacity of about 50 kwh.
あることを特徴とする請求項1記載のリチウム二次電
池。3. The lithium secondary battery according to claim 1, wherein the metal is fine particles having a particle size of 1000 ° or less.
ムと合金を形成しない金属の比率が、1:9〜9:1で
あることを特徴とする請求項1記載のリチウム二次電
池。4. The lithium secondary battery according to claim 1, wherein the ratio of the metal that forms an alloy with lithium and the metal that does not form an alloy with lithium is 1: 9 to 9: 1.
ウム二次電池を動力源とするモータを搭載することを特
徴とする電気自動車。5. An electric vehicle equipped with a motor using the lithium secondary battery according to claim 1 as a power source.
以上で350wh/l(電池容積)以上のエネルギー密度で
あることを特徴とする請求項5記載の電気自動車。6. The charge / discharge rate of a lithium secondary battery is 1 C
The electric vehicle according to claim 5, wherein the energy density is 350 wh / l (battery capacity) or more.
ウム二次電池を動力源とするモータを搭載することを特
徴とする自動二輪車。7. A motorcycle equipped with a motor using the lithium secondary battery according to claim 1 as a power source.
1C以上で、350wh/l(電池容積)以上のエネルギー
密度である請求項7記載の自動二輪車。8. The charge and discharge rate of the lithium secondary battery is as follows:
The motorcycle according to claim 7, wherein the energy density is not less than 1C and not less than 350 wh / l (battery capacity).
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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JP15511596A JP3188395B2 (en) | 1996-06-17 | 1996-06-17 | Lithium secondary battery |
US08/866,250 US6030726A (en) | 1996-06-17 | 1997-06-05 | Lithium secondary battery having negative electrode of carbon material which bears metals |
CN97112800A CN1086515C (en) | 1996-06-17 | 1997-06-16 | Lithium secondary battery |
KR1019970024797A KR19980086348A (en) | 1996-06-17 | 1997-06-16 | Lithium secondary battery |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP15511596A JP3188395B2 (en) | 1996-06-17 | 1996-06-17 | Lithium secondary battery |
Publications (2)
Publication Number | Publication Date |
---|---|
JPH103907A true JPH103907A (en) | 1998-01-06 |
JP3188395B2 JP3188395B2 (en) | 2001-07-16 |
Family
ID=15598919
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JP15511596A Expired - Fee Related JP3188395B2 (en) | 1996-06-17 | 1996-06-17 | Lithium secondary battery |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2767968A1 (en) * | 1997-08-28 | 1999-02-26 | Mitsubishi Pencil Co | NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY AND MANUFACTURING METHOD THEREOF |
US6203944B1 (en) * | 1998-03-26 | 2001-03-20 | 3M Innovative Properties Company | Electrode for a lithium battery |
EP1134828A4 (en) * | 1998-07-31 | 2002-01-16 | Finecell Co Ltd | Method for treating metallic aluminium and copper current collector for secondary cell |
JP2006252779A (en) * | 2005-03-08 | 2006-09-21 | Jfe Chemical Corp | Anode material for lithium-ion secondary battery, its manufacturing method, anode for lithium-ion secondary battery, and lithium-ion secondary battery |
JP2007095569A (en) * | 2005-09-29 | 2007-04-12 | Sanyo Electric Co Ltd | Lithium secondary battery |
US8029931B2 (en) | 2004-12-18 | 2011-10-04 | Samsung Sdi Co., Ltd. | Anode active material, method of preparing the same, and anode and lithium battery containing the material |
JP2014511010A (en) * | 2011-04-05 | 2014-05-01 | エルジー・ケム・リミテッド | Negative electrode active material for lithium secondary battery and method for producing the same |
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1996
- 1996-06-17 JP JP15511596A patent/JP3188395B2/en not_active Expired - Fee Related
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FR2767968A1 (en) * | 1997-08-28 | 1999-02-26 | Mitsubishi Pencil Co | NEGATIVE ELECTRODE FOR LITHIUM ION SECONDARY BATTERY AND MANUFACTURING METHOD THEREOF |
US6203944B1 (en) * | 1998-03-26 | 2001-03-20 | 3M Innovative Properties Company | Electrode for a lithium battery |
US6436578B2 (en) * | 1998-03-26 | 2002-08-20 | 3M Innovative Properties Company | Electrode compositions with high coulombic efficiencies |
EP1134828A4 (en) * | 1998-07-31 | 2002-01-16 | Finecell Co Ltd | Method for treating metallic aluminium and copper current collector for secondary cell |
US8029931B2 (en) | 2004-12-18 | 2011-10-04 | Samsung Sdi Co., Ltd. | Anode active material, method of preparing the same, and anode and lithium battery containing the material |
JP2006252779A (en) * | 2005-03-08 | 2006-09-21 | Jfe Chemical Corp | Anode material for lithium-ion secondary battery, its manufacturing method, anode for lithium-ion secondary battery, and lithium-ion secondary battery |
JP2007095569A (en) * | 2005-09-29 | 2007-04-12 | Sanyo Electric Co Ltd | Lithium secondary battery |
JP2014511010A (en) * | 2011-04-05 | 2014-05-01 | エルジー・ケム・リミテッド | Negative electrode active material for lithium secondary battery and method for producing the same |
US9735418B2 (en) | 2011-04-05 | 2017-08-15 | Lg Chem, Ltd. | Anode active material for lithium secondary battery and preparation thereof |
US9972828B2 (en) | 2011-04-05 | 2018-05-15 | Lg Chem, Ltd. | Anode active material for lithium secondary battery and preparation thereof |
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