JP2564175B2 - Method for producing positive electrode active material for non-aqueous electrolyte secondary battery - Google Patents
Method for producing positive electrode active material for non-aqueous electrolyte secondary batteryInfo
- Publication number
- JP2564175B2 JP2564175B2 JP63173400A JP17340088A JP2564175B2 JP 2564175 B2 JP2564175 B2 JP 2564175B2 JP 63173400 A JP63173400 A JP 63173400A JP 17340088 A JP17340088 A JP 17340088A JP 2564175 B2 JP2564175 B2 JP 2564175B2
- Authority
- JP
- Japan
- Prior art keywords
- positive electrode
- active material
- manganese dioxide
- electrode active
- aqueous electrolyte
- 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.)
- Expired - Lifetime
Links
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/36—Selection of substances as active materials, active masses, active liquids
- H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
- H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
- H01M4/502—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese for non-aqueous cells
-
- 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
Description
【発明の詳細な説明】 産業上の利用分野 本発明は、負極にリチウムあるいはリチウム合金、電
解液に有機電解液を使用した非水電解液電池に関するも
のであり、電解二酸化マンガンを改良した正極活物質を
使用することにより、放電電圧が高くエネルギー密度が
大きく、充放電サイクル寿命の長い二次電池を提供する
ものである。Description: TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte battery using lithium or a lithium alloy for a negative electrode and an organic electrolyte for an electrolyte, and a positive electrode active material in which electrolytic manganese dioxide is improved. By using a substance, a secondary battery having a high discharge voltage, a high energy density, and a long charge / discharge cycle life is provided.
従来の技術 負極にリチウムあるいはリチウム合金、電解液に有機
電解液を使用した充放電可能な、いわゆる非水電解液二
次電池を得る試みは、さかんに行われており、正極活物
質としては、主に二硫化チタンや二硫化モリブデン等の
カルコゲン化合物が使用されてきた。［竹原 化学 37
168（1982）］ しかし、正極にカルコゲン化合物を使用した場合、放
電電圧が低く、したがってエネルギー密度は小さくな
る。また、多くのカルコゲン化合物は合成が困難で高価
である。2. Description of the Related Art Attempts to obtain a so-called non-aqueous electrolyte secondary battery that can be charged and discharged using lithium or a lithium alloy as an anode and an organic electrolyte as an electrolyte have been actively conducted. Chalcogen compounds such as titanium disulfide and molybdenum disulfide have been mainly used. [Takehara Chemical 37
168 (1982)] However, when a chalcogen compound is used for the positive electrode, the discharge voltage is low, and the energy density is low. Also, many chalcogen compounds are difficult and expensive to synthesize.
これらの欠点を克服するために、正極活物質として各
種酸化物を使用することが検討され、その中でも電解二
酸化マンガンが、リチウムと組み合わせた場合、平均放
電電圧が2.8Vと高いことや、工業的生産が可能で安価な
ことから、二次電池への応用が期待されている。In order to overcome these drawbacks, the use of various oxides as a positive electrode active material has been studied.In particular, when electrolytic manganese dioxide is combined with lithium, the average discharge voltage is as high as 2.8 V, Since production is possible and inexpensive, application to secondary batteries is expected.
ところが、有機電解液中の電解二酸化マンガンを充放
電する場合の反応は、二酸化マンガン結晶中へのリチウ
ムイオンの出入りであるため、充放電によって二酸化マ
ンガンの体積は膨張と収縮を繰り返し、次第に結晶構造
が崩壊することや、二酸化マンガンの結晶と導電材との
接触が悪くなって、サイクル数の増大と共に放電容量が
減少するという問題点を有していた。［G.Pistoia J.El
ectrochem.Soc.,129 1861（1982）］ よって電解二酸化マンガンを使用した非水電解液電池
に見られるこのようなサイクル数の増大にともなう放電
容量の減少という欠点を取り除き、放電電圧が高く、放
電容量が大きく、エネルギー密度の大きい非水電解液二
次電池を得ることが課題とされていた。However, the reaction when charging and discharging electrolytic manganese dioxide in the organic electrolytic solution is the movement of lithium ions in and out of the manganese dioxide crystal, so the volume of manganese dioxide repeats expansion and contraction due to charging and discharging, and the crystal structure gradually increases. However, there is a problem in that the discharge capacity decreases with an increase in the number of cycles due to the collapse of the particles and the poor contact between the manganese dioxide crystal and the conductive material. [G. Pistoia J. El
ectrochem.Soc., 129 1861 (1982)] Therefore, the disadvantage of the decrease in discharge capacity with the increase in the number of cycles, which is observed in the non-aqueous electrolyte battery using electrolytic manganese dioxide, is eliminated, and the discharge voltage is high, It has been a subject to obtain a non-aqueous electrolyte secondary battery having a large capacity and a large energy density.
課題を解決するための手段 本発明は、負極にリチウムあるいはリチウム合金を用
いた非水電解液二次電池において、正極活物質として電
解二酸化マンガン中に銀の微粒子を分散させたものを用
いたことを特徴とする。また、前記正極活物質の製造方
法として電解二酸化マンガンに15wt％以下の炭酸銀を加
え220℃以上350℃以下の温度で加熱することを特徴とす
る。Means for Solving the Problems The present invention uses a non-aqueous electrolyte secondary battery in which lithium or a lithium alloy is used for a negative electrode, in which fine silver particles are dispersed in electrolytic manganese dioxide as a positive electrode active material. Is characterized by. As a method for producing the positive electrode active material, 15 wt% or less of silver carbonate is added to electrolytic manganese dioxide and heated at a temperature of 220 ° C. or higher and 350 ° C. or lower.
作用 電解二酸化マンガンを非水電解液電池の活物質に使用
する場合、結晶中に含まれている水分をある程度除去す
るために、一定の温度で加熱脱水する方法がとられてい
る。本発明の電解二酸化マンガンを加熱脱水する際、あ
らかじめ電解二酸化マンガンに一定量の炭酸銀（Ag2C
O3）を添加しておき、加熱によって炭酸銀が分解して銀
の微粒子が生成し、これが二酸化マンガン中に分散する
ことを利用するものである。Action When using electrolytic manganese dioxide as an active material of a non-aqueous electrolyte battery, a method of heating and dehydrating at a constant temperature is used in order to remove water contained in crystals to some extent. When the electrolytic manganese dioxide of the present invention is heated and dehydrated, a certain amount of silver carbonate (Ag 2 C
O 3 ) is added, and silver carbonate is decomposed by heating to produce fine silver particles, which are dispersed in manganese dioxide.
ただし、炭酸銀の分解温度は218℃であるので、加熱
温度は220℃以上としなければならない。また、電解二
酸化マンガンは室温では含水のγ−型結晶構造であり、
加熱によって脱水するが、250℃以上ではγ−型とβ−
型の結晶構造の混合物、350℃以上ではβ−型結晶構造
となる。電池の充放電を行なう場合はβ−型よりもγ−
型結晶構造の方が望ましいため、加熱温度は350℃以下
とする必要がある。However, since the decomposition temperature of silver carbonate is 218 ° C, the heating temperature must be 220 ° C or higher. Further, electrolytic manganese dioxide has a γ-type crystal structure containing water at room temperature,
Dehydrates by heating, but at temperatures above 250 ° C, γ-type and β-type
A mixture of crystal structures of a type, and a β-type crystal structure at 350 ° C or higher. When charging and discharging the battery, γ-
Since the type crystal structure is preferable, the heating temperature needs to be 350 ° C. or lower.
本発明になる正極活物質は、電解二酸化マンガンから
の水分の離脱と、炭酸銀の分解が同時に起こる条件で合
成される。したがって、生成物は二酸化マンガン中に微
細な銀粉が分散した状態となっている。そのため、二酸
化マンガン結晶が充放電によって膨張収縮する場合にお
いても、結晶間に存在する銀のために、結晶間や導電剤
との接触が良好な状態で保たれ、ほとんどの二酸化マン
ガンが反応に使われる。また、銀が二酸化マンガン結晶
中に入って、二酸化マンガンの結晶を充放電しない状態
においても、あらかじめ膨張させておくので、充放電に
おけるリチウムの出入りに伴う体積変化を、電解二酸化
マンガン単独の場合よりも小さくするという効果があ
る。The positive electrode active material according to the present invention is synthesized under the condition that water is released from electrolytic manganese dioxide and decomposition of silver carbonate occurs at the same time. Therefore, the product is in a state where fine silver powder is dispersed in manganese dioxide. Therefore, even when the manganese dioxide crystals expand and contract due to charge and discharge, due to the silver existing between the crystals, good contact is maintained between the crystals and with the conductive agent, and most of the manganese dioxide is used for the reaction. Be seen. Further, even when the silver enters the manganese dioxide crystal and the crystal of the manganese dioxide is not charged and discharged, it is expanded in advance, so that the volume change due to the inflow and outflow of lithium during charge and discharge is smaller than that of the electrolytic manganese dioxide alone. Also has the effect of making it smaller.
実施例 以下に本発明を好適な実施例を用いて説明する。Examples Hereinafter, the present invention will be described using preferred examples.
［1.正極活物質の合成方法］ 電解二酸化マンガン（γ−型結晶構造）粉末と、炭酸
銀粉末とを一定の割合で均等に混合し、ルツボに入れ電
気炉中で５時間加熱した。混合比および加熱温度は第１
表に示す通りである。[1. Method for Synthesizing Positive Electrode Active Material] Electrolytic manganese dioxide (γ-type crystal structure) powder and silver carbonate powder were uniformly mixed at a constant ratio, put in a crucible and heated in an electric furnace for 5 hours. Mixing ratio and heating temperature are first
As shown in the table.
なお、生成物中の二酸化マンガンの含有量（wt％）は
加熱前の混合物に比べて、炭酸銀中のCO3が熱分解によ
って失われるため、第１表の値よりやや大きくなる。 The content (wt%) of manganese dioxide in the product is slightly larger than the value in Table 1 because CO 3 in silver carbonate is lost by thermal decomposition compared to the mixture before heating.
［2.正極板の製法］ 上記の正極活物質とアセチレンブラック（導電剤）と
ディスパージョンテフロンとを重量比で90:8:2となるよ
うに混合し、ペースト状とし、ニッケルリード線を取り
付けた10mm×10mmのエキスパンドニッケルグリッド上に
塗布した。正極混合物の塗布量な極板１枚当り約50mgと
した。これを加圧して均一な表面とした後、200℃で20
時間真空乾燥して余分の水を脱水した。[2. Manufacturing method of positive electrode plate] The above positive electrode active material, acetylene black (conductive agent), and dispersion Teflon were mixed at a weight ratio of 90: 8: 2 to form a paste, and a nickel lead wire was attached. It was coated on a 10 mm x 10 mm expanded nickel grid. The amount of the positive electrode mixture applied was about 50 mg per one electrode plate. After pressurizing it to make a uniform surface,
Excess water was dehydrated by vacuum drying for hours.
［3.電池の試作と試験条件］ 電池は正極板１枚と負極板１枚とで構成されている。
負極板は10mm×10mmのリチウム板にニッケルリード線を
圧着で取り付けたものである。セパレータとしては微細
孔を備えたポリプロピレンシートを使用し、電解液とし
ては２−メチルテトラヒドロフランに六フッ化砒酸リチ
ウム（LiAsF6）を1.5mol/溶解させた非水電解液を使
用した。[3. Prototype of Battery and Test Conditions] The battery is composed of one positive electrode plate and one negative electrode plate.
The negative electrode plate is obtained by attaching a nickel lead wire to a 10 mm × 10 mm lithium plate by crimping. A polypropylene sheet having micropores was used as a separator, and a non-aqueous electrolyte in which lithium hexafluoroarsenate (LiAsF 6 ) was dissolved in 2-methyltetrahydrofuran at 1.5 mol / mol was used as an electrolyte.
この極板群をテフロンケースに入れ、全体をセパラブ
ルフラスコ中、アルゴン雰囲気に密閉して、充放電試験
を行なった。充放電試験条件は以下の通りである。The electrode group was placed in a Teflon case, the whole was sealed in a separable flask in an argon atmosphere, and a charge / discharge test was performed. The charge / discharge test conditions are as follows.
温度:25℃±２℃ 電流：充放電とも1.0mA/cell定電流 終止電圧：（充電）3.50V,（放電）2.00V ［4.充放電試験結果］ 活物質No.1〜No.6を用いた電池について、正極活物質
合成時の炭酸銀の添加量と、正極活物質1kg当りの放電
容量との関係を第１図に示す。ただし、放電容量はサイ
クル数で変化するので、以下全て10サイクル目の値を比
較する。放電容量は炭酸銀添加量が5wt％のとき最大と
なり、添加量を増すと減少する。炭酸銀の添加量が15wt
％以下であれば、無添加の場合に比べて放電容量は大き
くなる。Temperature: 25 ℃ ± 2 ℃ Current: 1.0mA / cell constant current for both charge and discharge Final voltage: (Charge) 3.50V, (Discharge) 2.00V [4. Charge / Discharge test result] Active materials No.1 to No.6 For the battery used, the relationship between the amount of silver carbonate added during the synthesis of the positive electrode active material and the discharge capacity per 1 kg of the positive electrode active material is shown in FIG. However, since the discharge capacity changes with the number of cycles, the values in the tenth cycle are all compared below. The discharge capacity becomes maximum when the amount of silver carbonate added is 5 wt% and decreases when the amount added is increased. Addition amount of silver carbonate is 15wt
If it is less than%, the discharge capacity becomes larger than that in the case of no addition.
活物質No.2とNo.7〜No.10を用いた電池について、炭
酸銀を5wt％添加した場合の加熱温度と放電容量との関
係を第２図に示す。放電容量は300℃加熱の場合に最大
となり、加熱温度がこれより低くなっても、高くなって
も、小さくなる。この理由は、炭酸銀の分解温度数218
℃であるため、これ以下では二酸化マンガン中への銀の
侵入は無く、また、二酸化マンガンは室温ではγ−型結
晶構造であるが、加熱によって脱水されて、250〜350℃
の範囲ではγ／β−型結晶構造に、350〜450℃の範囲で
はβ−型結晶構造となって350℃以上での加熱では、充
放電に適さない結晶構造となってしまう。したがって、
正極活物質の加熱温度は、220℃以上350℃以下の範囲が
適している。FIG. 2 shows the relationship between the heating temperature and the discharge capacity when 5 wt% of silver carbonate was added to the batteries using the active materials No. 2 and No. 7 to No. 10. The discharge capacity is maximized when heating at 300 ° C., and decreases when the heating temperature is lower or higher. The reason is that the decomposition temperature of silver carbonate is 218.
Since it is ℃, below this there is no penetration of silver into manganese dioxide, and manganese dioxide has a γ-type crystal structure at room temperature, but is dehydrated by heating to 250 to 350 ° C.
In the above range, the crystal structure becomes γ / β-type, and in the range of 350 to 450 ° C., the crystal structure becomes β-type, and heating at 350 ° C. or higher results in a crystal structure not suitable for charge / discharge. Therefore,
The heating temperature of the positive electrode active material is suitably in the range of 220 ° C to 350 ° C.
活物質No.1（無添加）を用いた電池と、No.2（炭酸銀
5wt％添加）を用いた電池の、充放電サイクル数による
放電容量の変化を第３図に示す。炭酸銀を添加しない
と、放電容量のサイクル数による減少は激しいが、炭酸
銀を添加した場合の放電容量変化は非常に小さい。Batteries using active material No. 1 (no addition) and No. 2 (silver carbonate)
FIG. 3 shows the change in discharge capacity depending on the number of charge / discharge cycles of the battery using 5 wt% addition). If silver carbonate is not added, the discharge capacity decreases drastically with the number of cycles, but the change in discharge capacity when silver carbonate is added is very small.
発明の効果 本発明による正極活物質を使用すれば、充放電反応に
おいて極板中に含まれる大部分の二酸化マンガンが反応
に関与するため、同じ重量の電解二酸化マンガンを単独
で使用した場合よりも放電容量は大きくなる。しかも放
電電圧は二酸化マンガン単独の場合同様、平均2.8Vであ
るため、電池の放電エネルギー密度は極めて大きい。Effect of the Invention When the positive electrode active material according to the present invention is used, most of the manganese dioxide contained in the electrode plate is involved in the reaction in the charge / discharge reaction, so that the same weight of electrolytic manganese dioxide is used alone. The discharge capacity increases. Moreover, since the discharge voltage is an average of 2.8 V as in the case of manganese dioxide alone, the discharge energy density of the battery is extremely large.
また、銀が二酸化マンガンの結晶中に入るために、充
放電に伴う二酸化マンガン結晶の体積変化が体積変化が
小さく、結晶間の接触も良好な状態に保たれることによ
って、サイクル数による放電容量の減少は小さく、サイ
クル寿命の極めて長い二次電池が得られる。In addition, since the silver enters the manganese dioxide crystal, the volume change of the manganese dioxide crystal during charge and discharge is small, and the contact between the crystals is kept in a good state. Is small, and a secondary battery having an extremely long cycle life can be obtained.
なお、実施例においては負極にリチウム、電解液に２
−メチルテトラヒドロフン−六フッ化砒酸リチウムを使
用したが、負極はリチウムを含む合金、例えばリチウム
−アルミニウム合金等も使用でき、また、電解液もリチ
ウムと直接反応しない各種有機電解液の使用も可能であ
り、いずれの場合においても本発明の効果を得ることが
できる。In the examples, lithium was used for the negative electrode and 2 for the electrolyte.
-Methyltetrahydrofunnel-lithium hexafluoroarsenate was used, but an alloy containing lithium, such as a lithium-aluminum alloy, can also be used for the negative electrode, and various electrolytes that do not directly react with lithium can also be used. In any case, the effect of the present invention can be obtained.
第１図は、正極活物質合成時の炭酸銀含有量と、その活
物質を使った電池の放電容量との関係を示す図。第２図
は、正極活物質合成時の加熱温度と、電池の放電容量と
の関係を示す図。第３図は、本発明による電池および従
来の電池の充放電サイクル数と放電容量の関係を示した
図。FIG. 1 is a diagram showing the relationship between the silver carbonate content at the time of synthesizing a positive electrode active material and the discharge capacity of a battery using the active material. FIG. 2 is a diagram showing a relationship between a heating temperature during synthesis of a positive electrode active material and a discharge capacity of a battery. FIG. 3 is a diagram showing the relationship between the number of charge / discharge cycles and the discharge capacity of the battery according to the present invention and the conventional battery.
Claims (1)
を加え、220℃以上350℃以下の温度で加熱することを特
徴とする、負極にリチウムあるいはリチウム合金を用い
た非水電解液二次電池用正極活物質の製造方法。1. A non-aqueous electrolyte secondary battery using lithium or a lithium alloy for the negative electrode, characterized in that 15 wt% or less of silver carbonate is added to electrolytic manganese dioxide and heated at a temperature of 220 ° C. or higher and 350 ° C. or lower. A method for producing a positive electrode active material for a battery.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63173400A JP2564175B2 (en) | 1988-07-12 | 1988-07-12 | Method for producing positive electrode active material for non-aqueous electrolyte secondary battery |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63173400A JP2564175B2 (en) | 1988-07-12 | 1988-07-12 | Method for producing positive electrode active material for non-aqueous electrolyte secondary battery |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0224967A JPH0224967A (en) | 1990-01-26 |
| JP2564175B2 true JP2564175B2 (en) | 1996-12-18 |
Family
ID=15959713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63173400A Expired - Lifetime JP2564175B2 (en) | 1988-07-12 | 1988-07-12 | Method for producing positive electrode active material for non-aqueous electrolyte secondary battery |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2564175B2 (en) |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5435328A (en) * | 1977-08-24 | 1979-03-15 | Hitachi Ltd | Positiveeelectrode material for nonaqueous electrolyte battery and method of manufacture thereof |
-
1988
- 1988-07-12 JP JP63173400A patent/JP2564175B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5435328A (en) * | 1977-08-24 | 1979-03-15 | Hitachi Ltd | Positiveeelectrode material for nonaqueous electrolyte battery and method of manufacture thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0224967A (en) | 1990-01-26 |
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