JPH11145009A - Electric double layer capacitor - Google Patents
Electric double layer capacitorInfo
- Publication number
- JPH11145009A JPH11145009A JP9301913A JP30191397A JPH11145009A JP H11145009 A JPH11145009 A JP H11145009A JP 9301913 A JP9301913 A JP 9301913A JP 30191397 A JP30191397 A JP 30191397A JP H11145009 A JPH11145009 A JP H11145009A
- Authority
- JP
- Japan
- Prior art keywords
- activated carbon
- electrode
- potential
- double layer
- electric double
- 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
- Y02E60/13—Energy storage using capacitors
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、耐電圧、エネルギ
ー密度が大きく、急速充放電でき、耐久性に優れた電気
二重層キャパシターに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor which has a high withstand voltage, a high energy density, can be rapidly charged and discharged, and has excellent durability.
【０００２】[0002]
【従来の技術】大電流で充放電できる電気二重層キャパ
シターは、電気自動車、補助電源等の用途に有望であ
る。そのために、エネルギー密度が高く、急速充放電が
可能であり、高電圧印加時の耐久性及び充放電サイクル
耐久性に優れた電気二重層キャパシターの実現が望まれ
ている。2. Description of the Related Art Electric double layer capacitors which can be charged and discharged with a large current are promising for applications such as electric vehicles and auxiliary power supplies. Therefore, it is desired to realize an electric double layer capacitor having a high energy density, capable of rapid charge / discharge, and having excellent durability when a high voltage is applied and charge / discharge cycle durability.
【０００３】キャパシターのセルに蓄積されるエネルギ
ーは、１／２・Ｃ・Ｖ2 で算出され、Ｃはセル当たりの
容量（Ｆ）、Ｖはセルに印加可能な電圧（Ｖ）である。
印可可能電圧Ｖは、その値の二乗がエネルギーに反映さ
れるため、エネルギー密度の向上にはキャパシターに印
加する電圧を上げるの効果的であるが、大きな電圧では
電解液の分解が起こる。The energy stored in a capacitor cell is calculated by ・ · C · V 2 , where C is the capacity per cell (F) and V is the voltage (V) that can be applied to the cell.
Since the square of the value of the applicable voltage V is reflected in the energy, it is effective to increase the voltage applied to the capacitor to improve the energy density. However, at a large voltage, the decomposition of the electrolytic solution occurs.
【０００４】そのため、従来の電気二重層キャパシター
では使用する電解液の溶媒と溶質の種類にもよるが、単
位セルあたりの耐電圧は、非水系電解液の電気二重層キ
ャパシターの場合、約２．４Ｖであり（特開平７−１４
５００１号公報）、２．５Ｖ以上の高電圧で使用する
と、内部直列抵抗の増加あるいは静電容量の減少が短時
間で発生する。そこで、正負側の電極、セパレータ、電
解液、容器等を詳細に検討し、２．５Ｖ〜２．８Ｖの電
圧を印加することが試みられている。例えば、フェノー
ル樹脂、石油コークス等をＫＯＨ賦活して得られる活性
炭を用いた電極を不活性雰囲気中で熱処理して耐久性は
向上するさせる方法や、原料を選定した結果、フェノー
ル樹脂、フラン樹脂、ポリアクリロニトリル樹脂の場合
に耐久性がわずかに向上したこと（特開平８−１６２３
７５号公報）、キャパシターの集電体に多孔質アルミニ
ウムを用いて耐久性向上を図る手法（特開平８−３３９
９４１号公報）等が知られている。[0004] For this reason, the withstand voltage per unit cell of a conventional electric double layer capacitor depends on the type of the solvent and the solute of the electrolytic solution used. 4 V (Japanese Unexamined Patent Publication No. 7-14)
If the battery is used at a high voltage of 2.5 V or more, an increase in internal series resistance or a decrease in capacitance occurs in a short time. Therefore, positive and negative electrodes, separators, electrolytes, containers, and the like have been examined in detail, and attempts have been made to apply a voltage of 2.5 V to 2.8 V. For example, phenolic resin, petroleum coke, etc. are activated by KOH activation. An electrode using activated carbon is heat-treated in an inert atmosphere to improve durability. As a result of selecting raw materials, phenolic resin, furan resin, The durability was slightly improved in the case of polyacrylonitrile resin (JP-A-8-1623).
No. 75), a method of improving durability by using porous aluminum as a current collector of a capacitor (JP-A-8-339).
No. 941) is known.
【０００５】エネルギー密度を大きくするため、印加電
圧を３Ｖ以上にする方法としては、特開平８−１０７０
４８号公報にリチウム箔を接触させてリチウムを吸蔵さ
せた黒鉛電極を負極に、活性炭を正極に、リチウムイオ
ンを溶質に含んだ電解液を用いたキャパシターや特開平
９−２３２１９０号公報では、活性炭粉末を含む分極性
電極材料にステンレス鋼繊維の集電体が混在状態で組み
合わしたものを正極としたキャパシターが提案されてい
る。また、特開平９−２０５０４１号公報では、電解液
に２−メチルスルホランを溶媒の主体とする電解液を用
いて、耐電圧の向上を図っている。As a method of increasing the applied voltage to 3 V or more in order to increase the energy density, Japanese Patent Application Laid-Open No.
JP-A-9-232190 discloses a capacitor using an electrolytic solution containing lithium ion as a solute, a graphite electrode having lithium foil in contact with a lithium foil and activating carbon as a positive electrode, and JP-A-9-232190 discloses an activated carbon. A capacitor has been proposed in which a polarizable electrode material containing powder and a stainless steel fiber current collector combined in a mixed state are used as a positive electrode. In JP-A-9-205041, the withstand voltage is improved by using an electrolytic solution mainly composed of 2-methylsulfolane as a solvent for the electrolytic solution.
【０００６】[0006]
【発明が解決すべき課題】しかしながらこれらの例は、
いずれの程度の差こそあれ満足すべきものではなかっ
た。例えば前述の、フェノール樹脂、石油コークス等を
ＫＯＨ賦活して得られる活性炭を用いた電極を不活性雰
囲気中で熱処理する方法では、同時に初期静電容量も小
さくなるという問題があった。また、特開平８−１６２
３７５号公報、特開平８−３３９９４１号公報の方法で
は、根本的には耐久性を改善することはできないと言っ
てよい。印加電圧を３Ｖ以上にすることによるエネルギ
ー密度向上策として、特開平９−２３２１９０号公報、
特開平９−２０５０４１号公報は、最大の印加電圧は
３．３Ｖであり、それより大きい電圧を印加することが
できない。また、特開平８−１０７０４８号公報の方法
では、電極−電解液間で酸化還元反応を伴うため、耐久
性が問題がある。また、負極（非分極性電極）にリチウ
ムを含有するため、未充電の状態ですでに正極（分極性
電極）は約３Ｖであり、記載の実施例のように４．３Ｖ
まで電圧を印加した場合の充電による電位変化は１．３
Ｖ程度となる。従って、キャパシターとして使用した場
合のエネルギー密度は通常のキャパシターより小さくな
る。However, these examples are:
Any difference was not satisfactory. For example, the above-described method of heat-treating an electrode using activated carbon obtained by activating a phenol resin, petroleum coke or the like with KOH in an inert atmosphere has a problem that the initial capacitance is also reduced at the same time. Also, JP-A-8-162
It can be said that durability cannot be fundamentally improved by the methods disclosed in Japanese Unexamined Patent Application Publication No. 375-375 and Japanese Unexamined Patent Application Publication No. 8-339994. As measures for improving the energy density by increasing the applied voltage to 3 V or more, JP-A-9-232190,
In Japanese Patent Application Laid-Open No. 9-205041, the maximum applied voltage is 3.3 V, and a higher voltage cannot be applied. In the method disclosed in Japanese Patent Application Laid-Open No. H08-107048, there is a problem in durability because an oxidation-reduction reaction is involved between the electrode and the electrolytic solution. Further, since lithium is contained in the negative electrode (non-polarizable electrode), the positive electrode (polarizable electrode) is already about 3 V in an uncharged state.
The potential change due to charging when a voltage is applied up to 1.3
V or so. Therefore, the energy density when used as a capacitor is smaller than that of a normal capacitor.
【０００７】従来の電気二重層キャパシターに用いたら
れた活性炭電極では、２．５Ｖを越える高電圧の連続印
加によって、ガス発生あるいは分極性電極上への反応生
成物の付着が発生していた。これが、原因となって、著
しい内部抵抗の増加あるいは静電容量の減少を起こすと
いう欠点を有していた。そこで、本発明者らは、特願平
９−１８３６７０号公報において、炭素質電極の自然電
位を任意に調節して充電時の電位を、電解液の高電位側
（酸化側）の実質的な分解開始電圧以下にすることによ
り、電解液の分解が抑制され、電気二重層キャパシター
の印加可能電圧、及び耐久性が改善できることを提案し
てる。In the activated carbon electrode used in the conventional electric double layer capacitor, continuous application of a high voltage exceeding 2.5 V generates gas or deposits of a reaction product on the polarizable electrode. This has the disadvantage of causing a significant increase in internal resistance or a decrease in capacitance. In view of this, the present inventors have disclosed in Japanese Patent Application No. 9-183670 that the natural potential of a carbonaceous electrode is arbitrarily adjusted so that the potential at the time of charging is substantially higher on the high potential side (oxidation side) of the electrolytic solution. It is proposed that by setting the voltage to be equal to or lower than the decomposition start voltage, decomposition of the electrolytic solution is suppressed, and the applicable voltage and durability of the electric double layer capacitor can be improved.
【０００８】これについて、簡単に説明する。代表的な
非水系の電解液である４級アルキルアンモニウム塩のプ
ロピレンカーボネート溶液の実質的に炭素質物質からな
る電極を用いた場合、電解液の酸化側の分解開始電圧は
４．４Ｖ（対Ｌｉ／Ｌｉ+ ）付近であると言われてい
る。一方、通常の活性炭電極の自然電位は３Ｖ（対Ｌｉ
／Ｌｉ+ ）付近であり、キャパシターの印加電圧が２．
８Ｖの場合、充電後の正極側の分極は約１．４Ｖとな
り、酸化側の電位は４．４Ｖ（対Ｌｉ／Ｌｉ+ ）以上を
示し、電解液の電気化学的分解がおこると考えられる。
その結果、従来の活性炭電極を用いた場合、その電解液
の分解により発生するガス等により容量は低下するた
め、長期間使用した場合に耐久性に問題であった。現行
の電気二重層キャパシターの印加電圧２．５Ｖ以上で使
用した場合、耐久性が低いのはキャパシターの正極、負
極の電位変化と電解液の分解電圧との関係にある。従っ
て、特願平９−１８３６７０号の発明では活性炭電極の
自然電位を下げて充電後の正極側の電位が電解液の酸化
分解開始電圧以下とすることによて、キャパシターの実
質的な印加可能電圧が大幅に増加し、エネルギー密度を
向上できることを見出した。[0008] This will be described briefly. When an electrode substantially consisting of a carbonaceous substance of a propylene carbonate solution of a quaternary alkylammonium salt, which is a typical non-aqueous electrolyte, is used, the decomposition start voltage on the oxidation side of the electrolyte is 4.4 V (vs. Li). / Li + ). On the other hand, the natural potential of a normal activated carbon electrode is 3 V (vs. Li
/ Li + ) and the voltage applied to the capacitor is 2.
In the case of 8 V, the polarization on the positive electrode side after charging is about 1.4 V, the potential on the oxidation side is 4.4 V (vs. Li / Li + ) or more, and it is considered that electrochemical decomposition of the electrolytic solution occurs.
As a result, when the conventional activated carbon electrode is used, the capacity is reduced due to gas or the like generated by decomposition of the electrolytic solution, and thus there is a problem in durability when used for a long period of time. When used at an applied voltage of 2.5 V or more of the current electric double layer capacitor, the durability is low because of the relationship between the potential change of the positive electrode and the negative electrode of the capacitor and the decomposition voltage of the electrolytic solution. Therefore, in the invention of Japanese Patent Application No. 9-183670, the potential of the capacitor can be substantially applied by lowering the natural potential of the activated carbon electrode so that the potential on the positive electrode side after charging is lower than the oxidative decomposition starting voltage of the electrolytic solution. It has been found that the voltage can be greatly increased and the energy density can be improved.
【０００９】しかしながら、高いエネルギー密度を有し
且つ高い耐久性を示す活性炭電極の自然電位の調節に最
適な物質及びその添加量については不明であった。ま
た、キャパシター用活性炭電極の最大電圧を印加した際
の電解液の分解が起こりにくい正極、負極の適切な電位
についても不明であった。[0009] However, it has been unknown which substance is most suitable for adjusting the natural potential of an activated carbon electrode having a high energy density and a high durability, and the amount of the substance added. Also, it was unclear about the appropriate potentials of the positive electrode and the negative electrode, which are unlikely to cause decomposition of the electrolytic solution when the maximum voltage of the activated carbon electrode for a capacitor is applied.
【００１０】[0010]
【発明が解決するための手段】そこで、本発明者らは、
上記の課題を検討すべく鋭意検討した結果、従来の電解
液を分解しにくいものにしたり、電極の不純物を低減さ
せたりするという方法とは異なる抜本的解決方法とし
て、非水系溶液を電解液とし、両極に活性炭を用いた印
加電圧が３．３５Ｖ以上とすることが可能な電気二重層
キャパシターにおいて、活性炭電極の自然電位を調節す
る物質及びその添加量を最適化して、最大電圧を印加し
た時の正極および負極の電位を非水系電解液の酸化また
は還元反応による分解が起こらない範囲にすることによ
り、高電圧印加時の耐久性を有し、かつ、エネルギー密
度が大きいキャパシターが得られることを見出し、本発
明に到達した。すなわち、本発明の目的は、３．３５Ｖ
以上の高電圧時の耐久性に優れ、かつエネルギー密度の
大きい電気二重層キャパシターを提供することにあり、
かかる目的は、活性炭電極両極中に含まれるＬｉ量が
０．０２重量％以上２重量％以下とし、かつ、活性炭電
極に最大許容印加電圧を印加した時の該電解液中での正
極側の電位がＬｉ／Ｌｉ+ を対極とした場合、３．５Ｖ
以上４．２Ｖ以下であり、かつ該電解液中での負極側で
の電位がＬｉ／Ｌｉ+ を対極とした場合、０．１Ｖ以上
０．８Ｖ以下とすることにより容易に達成される。尚、
最大許容印加電圧とは、電解液が分解したりする等、キ
ャパシターに実用上、不可逆なダメージを与えることな
く印加できる最大電圧のことを言う。Means for Solving the Problems Accordingly, the present inventors have
As a result of diligent studies to study the above problems, as a drastic solution different from the method of making the conventional electrolyte difficult to decompose or reducing the impurities of the electrode, a non-aqueous solution was used as the electrolyte. When the maximum voltage is applied by optimizing the substance that adjusts the natural potential of the activated carbon electrode and the amount of addition thereof in an electric double layer capacitor that can apply an applied voltage of 3.35 V or more using activated carbon to both electrodes. By setting the potential of the positive electrode and the negative electrode of the non-aqueous electrolyte to a range that does not cause decomposition by oxidation or reduction of the non-aqueous electrolyte, it is possible to obtain a capacitor having durability at the time of applying a high voltage and having a large energy density. Heading, the present invention has been reached. That is, the object of the present invention is to provide 3.35 V
In providing an electric double layer capacitor having excellent durability at the time of the above high voltage and having a large energy density,
The purpose is to make the amount of Li contained in both electrodes of the activated carbon electrode 0.02% by weight or more and 2% by weight or less, and to apply the maximum allowable applied voltage to the activated carbon electrode to the potential on the positive electrode side in the electrolytic solution. Is 3.5 V when Li / Li + is used as a counter electrode.
When the potential is 4.2 V or less and the potential on the negative electrode side in the electrolytic solution is Li / Li + as a counter electrode, it is easily achieved by setting the potential to 0.1 V or more and 0.8 V or less. still,
The maximum allowable applied voltage refers to the maximum voltage that can be applied without practically irreversible damage to the capacitor such as decomposition of the electrolytic solution.
【００１１】[0011]
【発明の実施の形態】以下、本発明を詳細に説明する。
本発明を最大の特徴は、非水系溶液を電解液とし、両極
に活性炭電極を用いた電気二重層キャパシターにおい
て、活性炭電極両極中のＬｉ量が０．０２重量％以上２
重量％以下として自然電位を下げた電極を用いると活性
炭電極に最大許容電圧を印加した時の該電解液中での正
極側の電位が、３．５Ｖ以上４．２Ｖ以下（対Ｌｉ／Ｌ
ｉ+ ）であり、かつ負極側での電位が０．１Ｖ以上０．
８Ｖ以下（対Ｌｉ／Ｌｉ+ ）とすることにより、３．３
５Ｖ以上の高電圧を印加してもキャパシターの破壊が生
じず、エネルギー密度を大幅に改善することができる点
にある。DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The greatest feature of the present invention is that in an electric double layer capacitor using a non-aqueous solution as an electrolyte and activated carbon electrodes for both electrodes, the amount of Li in the activated carbon electrodes is 0.02% by weight or more.
When an electrode whose natural potential is lowered to not more than% by weight is used, the potential on the positive electrode side in the electrolytic solution when the maximum allowable voltage is applied to the activated carbon electrode is 3.5 V or more and 4.2 V or less (vs. Li / L).
i + ), and the potential on the negative electrode side is 0.1 V or more.
By setting the voltage to 8 V or less (vs. Li / Li + ), 3.3
Even when a high voltage of 5 V or more is applied, the capacitor is not broken, and the energy density can be greatly improved.
【００１２】本発明において、活性炭電極中へリチウム
を導入することにより、電極の自然電位を下げる手法は
特に限定するものではないが、電気化学的手法、化学的
手法、物理的手法等により電極体に添加することが可能
である。例えば、簡便な方法の一つとして、非常に卑な
金属である金属リチウムまたはリチウムを含む物質から
なるリチウム含有電極、活性炭を主とする炭素質電極、
セパレータ及び非水系電解液で構成される電気化学セル
において、リチウム含有電極と炭素質電極を短絡または
リチウム含有電極を正極、炭素質電極を負極として充電
することにより活性炭電極中にリチウムを導入させるこ
とができる。リチウムを含む物質としては、特に限定す
るものではないが、例えば、リチウム−アルミニウム合
金、リチウム−マグネシウム合金等のリチウムを含む合
金、リチウム金属間化合物、リチウムを含むマンガン酸
化物、コバルト酸化物、ニッケル酸化物、バナジウム酸
化物等の複合酸化物、リチウムを含む硫化チタン、セレ
ン化ニオブ、硫化モリブデン等のカルコゲナイト、リチ
ウムを含む炭素から選ばれる少なくとも１つ以上の物質
を用いることが好ましい。卑な電位をもつ金属として、
リチウム以外に、ナトリウム、カリウム等のアルカリ金
属、カルシウム、マグネシウム等のアルカリ土類金属、
イットリウム、ネオジウム等の希土類金属または、これ
らの金属を含む物質をリチウムの場合と同様に自然電位
を下げる物質として用いてもよい。In the present invention, the method of lowering the natural potential of the electrode by introducing lithium into the activated carbon electrode is not particularly limited, but the electrode body may be formed by an electrochemical method, a chemical method, a physical method, or the like. Can be added. For example, as one of the simple methods, a lithium-containing electrode made of a material containing lithium or lithium which is a very noble metal, a carbonaceous electrode mainly containing activated carbon,
In an electrochemical cell composed of a separator and a non-aqueous electrolyte, lithium is introduced into an activated carbon electrode by short-circuiting a lithium-containing electrode and a carbonaceous electrode or charging the lithium-containing electrode as a positive electrode and the carbonaceous electrode as a negative electrode. Can be. Examples of the substance containing lithium include, but are not particularly limited to, an alloy containing lithium such as a lithium-aluminum alloy and a lithium-magnesium alloy, a lithium intermetallic compound, a manganese oxide containing lithium, a cobalt oxide, and nickel. It is preferable to use at least one substance selected from oxides, composite oxides such as vanadium oxide, lithium-containing titanium sulfide, niobium selenide, chalcogenite such as molybdenum sulfide, and lithium-containing carbon. As a metal with a low potential,
In addition to lithium, alkali metals such as sodium and potassium, alkaline earth metals such as calcium and magnesium,
A rare earth metal such as yttrium or neodymium or a substance containing these metals may be used as a substance for lowering the natural potential as in the case of lithium.
【００１３】こうして得たリチウムが導入された活性炭
電極を少なくとも１つの極に用いて、電気二重層キャパ
シターを組み立てる。一方の極のみリチウムが導入され
た活性炭電極を用いると、動作が不安定になるため好ま
しくない。電極中の微量なリチウム量の定量は、ＩＣＰ
発光分析装置、原子吸光分光光度計等を用いることによ
り可能である。リチウムを添加した電極体の充電後の正
極及び負極の電位測定は、通常の電気化学的手法を用い
て行われる。非水系での電位測定は、水溶液での標準水
素電極のような電位基準は厳密には定義されていない
が、実際には、銀−塩化銀電極、白金電極、リチウム電
極等の電極を用いて一般に広く行われている。本発明に
おいても同様な方法で測定可能である。An electric double layer capacitor is assembled by using the thus obtained activated carbon electrode into which lithium has been introduced as at least one electrode. It is not preferable to use an activated carbon electrode in which lithium is introduced into only one of the electrodes, because the operation becomes unstable. The quantification of the trace amount of lithium in the electrode is determined by ICP
This is possible by using an emission spectrometer, an atomic absorption spectrophotometer, or the like. The potential measurement of the positive electrode and the negative electrode after the charging of the electrode body to which lithium is added is performed using a normal electrochemical method. In the measurement of potential in non-aqueous systems, the potential reference such as a standard hydrogen electrode in an aqueous solution is not strictly defined, but in practice, silver-silver chloride electrodes, platinum electrodes, lithium electrodes, and other electrodes are used. Generally done widely. In the present invention, it can be measured by a similar method.
【００１４】電極中のリチウムの含有量を０．０１重量
％以上２重量％以下、特に好ましくは０．２重量％以
上、２重量％以下にすることにより、活性炭の嵩密度、
比表面積、表面性状等により若干異なるにしても、活性
炭電極の充電後の電位が、正極側（酸化側）が３．８Ｖ
以上４．２Ｖ以下（対Ｌｉ／Ｌｉ+ ）かつ負極側（負極
側）での電位が０．１Ｖ以上０．８Ｖ以下（対Ｌｉ／Ｌ
ｉ+ ）となり非水系電解液の分解が起こりにくい電位範
囲に調節することができる。特に、キャパシター用電極
に好適な比表面積が約３００〜２３００ｍ2 ／ｇの活性
炭を電極に用いる場合、リチウムの含有量が０．０１重
量％以上１．５０重量％以下より好ましくは０．２重量
％以上、２重量％以下であることが好ましい。リチウム
の含有量が２重量％より大きい場合、キャパシターの充
放電時に、電極上への金属リチウム、リチウム化合物の
析出がおこり容量の低下を起こす場合がある。By setting the content of lithium in the electrode to 0.01% by weight or more and 2% by weight or less, particularly preferably 0.2% by weight or more and 2% by weight or less, the bulk density of the activated carbon is improved.
The potential after charging of the activated carbon electrode is 3.8 V on the positive electrode side (oxidation side) even if it slightly differs depending on the specific surface area, surface properties, etc.
4.2 V or less (vs. Li / Li + ) and the potential on the negative electrode side (negative electrode side) is 0.1 V or more and 0.8 V or less (vs. Li / L).
i + ) and can be adjusted to a potential range where decomposition of the non-aqueous electrolyte does not easily occur. In particular, when activated carbon having a specific surface area of about 300 to 2300 m 2 / g suitable for a capacitor electrode is used for the electrode, the lithium content is preferably 0.01% by weight or more and 1.50% by weight or less, more preferably 0.2% by weight or less. % Or more and 2% by weight or less. If the lithium content is more than 2% by weight, metal lithium or a lithium compound may be deposited on the electrode during charging and discharging of the capacitor, resulting in a decrease in capacity.
【００１５】リチウムを導入する前の活性炭は、電気二
重層キャパシターを大容量とするために比表面積の大き
な活性炭を用いるのが好ましい。活性炭の比表面積は大
きすぎると嵩密度が低下してエネルギー密度が低下する
ので、２００〜３０００ｍ2／ｇが好ましく、さらに好
ましくは３００〜２３００ｍ2 ／ｇである。活性炭の原
料としては、植物物系の木材、のこくず、ヤシ殻、パル
プ廃液、化石燃料系の石炭、石油重質油、あるいはそれ
らを熱分解した石炭および石油系ピッチ、タールピッチ
を紡糸した繊維、合成高分子、フェノール樹脂、フラン
樹脂、ポリ塩化ビニル樹脂、ポリ塩化ビニリデン樹脂、
ポリイミド樹脂、ポリアミド樹脂、液晶高分子、プラス
チック廃棄物、廃タイヤ等多種多用である。これらの原
料を炭化後、賦活するが、賦活法は、ガス賦活と薬品賦
活に大別される。ガス賦活法は、薬品賦活が化学的な活
性化であるのに対して、物理的な活性化ともいわれ、炭
化された原料を高温で水蒸気、炭酸ガス、酸素、その他
の酸化ガスなどと接触反応させて、活性炭が得られる。
薬品賦活法は、原料に賦活薬品を均等に含侵させて、不
活性ガス雰囲気中で加熱し、薬品の脱水および酸化反応
により活性炭を得る方法である。使用される薬品として
は、塩化亜鉛、りん酸、りん酸ナトリウム、塩化カルシ
ウム、硫化カリウム、水酸化カリウム、水酸化ナトリウ
ム、炭酸カリウム、炭酸ナトリウム、硫酸ナトリウム、
硫酸カリウム、炭酸カルシウム等がある。活性炭の製法
に関しては、上記に各種あげたが、特に問わない。活性
炭はの形状は、破砕、造粒、顆粒、繊維、フェルト、織
物、シート状等各種の形状があるが、いずれも本発明に
使用することができる。これらの活性炭のうち、ＫＯＨ
を用いた薬品賦活で得られる活性炭は、水蒸気賦活品と
比べて容量が大きい傾向にあることから、特に好まし
い。さらに好ましくは、水蒸気賦活後にＫＯＨ賦活する
ことである。As the activated carbon before lithium is introduced, it is preferable to use activated carbon having a large specific surface area in order to increase the capacity of the electric double layer capacitor. Since the specific surface area of the activated carbon is decreased is too large the bulk density energy density decreases, 200~3000m 2 / g are preferred, more preferably 300~2300m 2 / g. The raw materials of activated carbon were spun wood, wood, sawdust, coconut husk, pulp waste liquid, fossil fuel coal, petroleum heavy oil, or thermally decomposed coal, petroleum pitch, and tar pitch. Fiber, synthetic polymer, phenolic resin, furan resin, polyvinyl chloride resin, polyvinylidene chloride resin,
Polyimide resin, polyamide resin, liquid crystal polymer, plastic waste, waste tire, etc. These carbonized materials are activated after carbonization. Activation methods are roughly classified into gas activation and chemical activation. In the gas activation method, chemical activation is chemical activation, whereas physical activation is also called physical activation, and the carbonized raw material is contact-reacted with steam, carbon dioxide, oxygen, and other oxidizing gases at high temperatures. Then, activated carbon is obtained.
The chemical activation method is a method in which a raw material is uniformly impregnated with an activation chemical, heated in an inert gas atmosphere, and activated carbon is obtained by a dehydration and oxidation reaction of the chemical. The chemicals used include zinc chloride, phosphoric acid, sodium phosphate, calcium chloride, potassium sulfide, potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, sodium sulfate,
There are potassium sulfate, calcium carbonate and the like. Various methods for producing activated carbon have been described above, but are not particularly limited. Activated carbon has various shapes such as crushed, granulated, granulated, granular, fiber, felt, woven, and sheet shapes, and any of them can be used in the present invention. Of these activated carbons, KOH
Activated carbon obtained by chemical activation using is particularly preferable because it tends to have a larger capacity than a steam activated product. More preferably, KOH activation is performed after steam activation.
【００１６】賦活処理後の活性炭を、窒素、アルゴン、
ヘリウム、キセノン等の不活性雰囲気下で、５００〜２
５００℃、好ましくは７００〜１５００℃で熱処理し、
不要な表面官能基を除去したり、炭素の結晶性を発達さ
せて電子伝導性を増加させても良い。粒状の活性炭の場
合、電極の嵩密度の向上、内部抵抗の低減という点で、
平均粒子径は３０μｍ以下が好ましい。活性炭を主体と
する分極性電極は、活性炭、導電剤とバインダーから構
成される。分極性電極は、従来より知られている方法に
より成形することが可能である。例えば、活性炭とアセ
チレンブラックの混合物に、ポリテトラフルオロエチレ
ンを添加・混合した後、プレス成形して得られる。ま
た、導電剤、バインダーを用いず、活性炭のみを焼結し
て分極性電極とすることも可能である。電極は、薄い塗
布膜、シート状または板状の成形体、さらには複合物か
らなる板状成形体のいずれであっても良い。After the activation treatment, activated carbon is replaced with nitrogen, argon,
500 to 2 under an inert atmosphere such as helium or xenon
Heat treatment at 500C, preferably 700-1500C,
The electron conductivity may be increased by removing unnecessary surface functional groups or by developing the crystallinity of carbon. In the case of granular activated carbon, in terms of improving the bulk density of the electrode and reducing the internal resistance,
The average particle size is preferably 30 μm or less. A polarizable electrode mainly composed of activated carbon is composed of activated carbon, a conductive agent and a binder. The polarizable electrode can be formed by a conventionally known method. For example, it is obtained by adding and mixing polytetrafluoroethylene to a mixture of activated carbon and acetylene black, followed by press molding. Further, it is also possible to form a polarizable electrode by sintering only activated carbon without using a conductive agent and a binder. The electrode may be any of a thin coating film, a sheet-like or plate-like molded body, and a plate-like molded body made of a composite.
【００１７】分極性電極に用いられる導電剤として、ア
セチレンブラック、ケッチェンブラック等のカーボンブ
ラック、天然黒鉛、熱膨張黒鉛、炭素繊維、酸化ルテニ
ウム、酸化チタン、アルミニウム、ニッケル等の金属フ
ァイバーからなる群より選ばれる少なくとも一種の導電
剤が好ましい。少量で効果的に導電性が向上する点で、
アセチレンブラック及びケッチェンブラックが特に好ま
しく、活性炭との配合量は、活性炭の嵩密度により異な
るが多すぎると活性炭の割合が減り容量が減少するた
め、活性炭の重量の５〜５０％、特には１０〜３０％程
度が好ましい。バインダーとしては、ポリテトラフルオ
ロエチレン、ポリフッ化ビニリデン、カルボキシメチル
セルロース、フルオロオレフィン共重合体架橋ポリマ
ー、ポリビニルアルコール、ポリアクリル酸、ポリイミ
ド、石油ピッチ、石炭ピッチ、フェノール樹脂のうち少
なくとも１種類以上用いるのが好ましい。The conductive agent used for the polarizable electrode includes a group consisting of carbon black such as acetylene black and Ketjen black, natural graphite, thermally expanded graphite, carbon fiber, and metal fiber such as ruthenium oxide, titanium oxide, aluminum and nickel. At least one kind of conductive agent selected from the above is preferable. In terms of improving conductivity effectively with a small amount,
Acetylene black and Ketjen black are particularly preferred, and the amount of the activated carbon varies depending on the bulk density of the activated carbon. However, if the amount is too large, the proportion of the activated carbon is reduced and the capacity is reduced. About 30% is preferable. As the binder, it is preferable to use at least one or more of polytetrafluoroethylene, polyvinylidene fluoride, carboxymethylcellulose, a crosslinked polymer of fluoroolefin copolymer, polyvinyl alcohol, polyacrylic acid, polyimide, petroleum pitch, coal pitch, and phenol resin. preferable.
【００１８】集電体は電気化学的及び化学的に耐食性が
あればよく、特に限定するものではないが、例えば、正
極ではステンレス、アルミニウム、チタン、タンタルが
あり、負極では、ステンレス、ニッケル、銅等が好適に
使用される。非水系電解液の溶質は特に限定するもので
はないが、Ｒ４Ｎ+ 、Ｒ４Ｐ+ （ただし、ＲはＣn Ｈ
2n+1で示されるアルキル基）、トリエチルメチルアンモ
ニウムイオン等でなる第４級オニウムカチオン及び、リ
チウムイオン、カリウムイオン等のアルカリ金属カチオ
ンと、ＢＦ4 - 、ＰＦ6 - 、ＣｌＯ4 - 、またはＣＦ3
ＳＯ3 - なるアニオンとを組み合わせた塩を使用するの
が好ましい。これらの塩の非水系電解液中の濃度は電気
二重層キャパシターの特性が十分引き出せるように、
０．１〜２．５モル／リットル、特に、０．３〜２．０
モル／リットルが好ましい。また、非水系電解液の溶質
は特に限定するものではないが、プロピレンカーボネー
ト、エチレンカーボネート、ブチレンカーボネート、ジ
メチルカーボネート、メチルエチルカーボネート、ジエ
チルカーボネート、スルホラン、メチルスルホラン、γ
−ブチロラクトン、γ−バレロラクトン、Ｎ−メチルオ
キサゾリジノン、ジメチルスルホキシド、及びトリメチ
ルスルホキシドから選ばれる１種類以上からなる有機溶
媒が好ましい。電気化学的及び化学的安定性、電気伝導
性に優れる点から、プロピレンカーボネート、エチレン
カーボネート、ブチレンカーボネート、ジメチルカーボ
ネート、メチルエチルカーボネート、ジエチルカーボネ
ート、スルホラン、メチルスルホラン、γ−ブチロラク
トンから選ばれる１種類以上の有機溶媒が特に好まし
い。高い耐電圧が得られるように、非水系電解液中の水
分は２００ｐｐｍ以下、さらには５０ｐｐｍ以下が好ま
しい。The current collector is not particularly limited as long as it has corrosion resistance electrochemically and chemically. Examples of the current collector include stainless steel, aluminum, titanium and tantalum for the positive electrode, and stainless steel, nickel and copper for the negative electrode. Etc. are preferably used. Although the solute of the non-aqueous electrolyte is not particularly limited, R4N + , R4P + (where R is C n H
A quaternary onium cation such as an alkyl group represented by 2n + 1 ), triethylmethylammonium ion, or the like; and an alkali metal cation such as lithium ion or potassium ion, and BF 4 − , PF 6 − , ClO 4 − , or CF. Three
SO 3 - becomes preferable to use a combined salt and anion. The concentration of these salts in the non-aqueous electrolyte solution is adjusted so that the characteristics of the electric double layer capacitor can be sufficiently obtained.
0.1-2.5 mol / l, especially 0.3-2.0
Mole / liter is preferred. Further, the solute of the non-aqueous electrolyte is not particularly limited, but propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, sulfolane, methyl sulfolane, γ
Preferred is an organic solvent comprising at least one selected from -butyrolactone, γ-valerolactone, N-methyloxazolidinone, dimethyl sulfoxide, and trimethyl sulfoxide. At least one selected from propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, sulfolane, methyl sulfolane, and γ-butyrolactone from the viewpoint of excellent electrochemical and chemical stability and electric conductivity. Is especially preferred. In order to obtain a high withstand voltage, the water content in the non-aqueous electrolyte is preferably 200 ppm or less, more preferably 50 ppm or less.
【００１９】[0019]
【実施例】以下、本発明を具体的な実施例で説明する
が、本発明は以下の実施例により限定されない。 （実施例１）はじめに、活性炭電極へのリチウムの添加
方法について述べる。ＫＯＨ賦活処理して得られたリチ
ウム元素を含まないコークス系活性炭粉末（比表面積１
５５０ｍ2 ／ｇ、平均粒子径１０μｍ）８０重量％、ア
セチレンブラック１０重量％、ポリテトラフルオロエチ
レン１０重量％からなる混合物を混練した後、日本分光
製錠剤成型器を用い、油圧プレスで直径１０ｍｍ，厚さ
０．５ｍｍとなるように５０ｋｇｆ／ｃｍ2 の圧力で加
圧成形して円盤状の成型体を得た。この成型体を０．１
ｔｏｒｒ以下の真空中、３００℃で３時間乾燥し電極体
とした。この方法で作製した２枚の電極の間に三菱化学
製ポリエチレン製セパレータを入れた後、集電体に使う
白金板２枚で全体を挟み込み、さらに集電体、活性炭電
極、セパレータがよく接触するように一番外側から２枚
の厚さ５ｍｍで４個のボルト孔をもつテフロン板で挟み
込んで、オープンセル型キャパシターを組み立てた。こ
うして得たオープンセル型キャパシターと白金板の先端
に金属リチウム箔を圧着することにより作製したリチウ
ム極をビーカー内の１モル／リットルの濃度のＬｉＢＦ
4 のプロピレンカーボネート溶液中に浸漬させた。次
に、リチウム極と活性炭電極をリード線でつなぎ、約１
時間短絡させた。その後、電極部を分解して活性炭電極
体２枚を取り出した。得た活性炭電極中のリチウム含有
量をバリアンインスツルメントリミテッド社製Ｓｐｅｃ
ｔｒ ＡＡ−４０Ｐ型原子吸光分光光度計により定量し
たところ、０．２６重量％であった。また、オープンセ
ル型キャパシターに北斗電工製充放電装置「ＨＪ２０１
−Ｂ」を用いて、室温下で３．４Ｖの電圧を１時間印加
した後の正極側の電位は４．０Ｖ（対Ｌｉ／Ｌｉ+ ）、
負極側の電位は０．６Ｖ（対Ｌｉ／Ｌｉ+ ）を示した。
同様に、３．８Ｖを印加した場合、正極側は、４．２Ｖ
（対Ｌｉ／Ｌｉ+ ）、負極側は０．４Ｖ（対Ｌｉ／Ｌｉ
+ ）の電位を示した。EXAMPLES Hereinafter, the present invention will be described with reference to specific examples, but the present invention is not limited to the following examples. (Example 1) First, a method of adding lithium to an activated carbon electrode will be described. Coke-based activated carbon powder not containing lithium element obtained by KOH activation treatment (specific surface area 1
550 m 2 / g, average particle diameter 10 μm) After kneading a mixture consisting of 80% by weight, acetylene black 10% by weight, and polytetrafluoroethylene 10% by weight, using a tablet press made by JASCO, a hydraulic press was used to make a 10 mm diameter, Pressure molding was performed at a pressure of 50 kgf / cm 2 so as to have a thickness of 0.5 mm to obtain a disk-shaped molded body. 0.1%
The electrode was dried at 300 ° C. for 3 hours in a vacuum of not more than torr. A polyethylene separator made by Mitsubishi Chemical is put between the two electrodes made by this method, and then the whole is sandwiched between two platinum plates used for the current collector, and the current collector, the activated carbon electrode, and the separator come into good contact. Thus, an open-cell capacitor was assembled by sandwiching two Teflon plates having a thickness of 5 mm and four bolt holes from the outermost side. The open-cell capacitor thus obtained and a lithium electrode produced by crimping a metal lithium foil on the tip of a platinum plate were connected to a 1 mol / liter LiBF in a beaker.
4 was immersed in a propylene carbonate solution. Next, connect the lithium electrode and the activated carbon electrode with a lead wire.
Short-circuited for hours. Thereafter, the electrode portion was disassembled and two activated carbon electrode bodies were taken out. The lithium content in the obtained activated carbon electrode was measured by using Spec manufactured by Varian Instruments Limited.
It was 0.26% by weight as determined by tr AA-40P type atomic absorption spectrophotometer. In addition, Hokuto Denko's charge / discharge device “HJ201
-B ", the potential on the positive electrode side after applying a voltage of 3.4 V for 1 hour at room temperature is 4.0 V (vs. Li / Li + );
The potential on the negative electrode side was 0.6 V (vs. Li / Li + ).
Similarly, when 3.8 V is applied, 4.2 V is applied to the positive electrode side.
(Vs. Li / Li + ), 0.4 V (vs. Li / Li) on the negative electrode side
+ ) Potential.
【００２０】次に、リチウムを添加した活性炭電極を用
いたキャパシターの作製方法について述べる。上記の方
法で得たリチウムを含有する活性炭電極２枚に１モル／
リットルの濃度の（Ｃ2 Ｈ5 ）4 ＮＢＦ4 のプロピレン
カーボネート＋エチレンカーボネート溶液を充分に含浸
させたものを各々正極、負極とし、ポリエチレンセパレ
ータを両極間に配置して図１に示すようなコインセル型
電気二重層キャパシターを得た。得た電気二重層キャパ
シターに、北斗電工製充放電装置「ＨＪ２０１−Ｂ」を
用いて、室温下で３．４Ｖの電圧を１時間印加した後、
１．１６ｍＡで１．０Ｖまで定電流放電して求めた初期
のエネルギー密度は、１５．１Ｗｈ／ｌであった。同様
に３．８Ｖを印加したときのエネルギー密度は、１９．
２Ｗｈ／ｌであった。電圧印加条件下におけるキャパシ
ターの長期的な作動信頼性を評価するため、このキャパ
シターを３．４Ｖの電圧を印加し、５００時間経過後の
エネルギー密度は１４．５Ｗｈ／ｌ（−４％）となり殆
ど低下はなかった。また、印加電圧３．８Ｖで５００時
間経過後のエネルギー密度は、１８．２Ｗｈ／ｌ（−５
％）であり初期の密度と比べて殆ど変化はなかった。Next, a method of manufacturing a capacitor using an activated carbon electrode to which lithium is added will be described. 1 mol / mol is applied to two lithium-containing activated carbon electrodes obtained by the above method.
A coin cell as shown in FIG. 1 was obtained by sufficiently impregnating a liter concentration of (C 2 H 5 ) 4 NBF 4 in propylene carbonate + ethylene carbonate to form a positive electrode and a negative electrode, respectively, and a polyethylene separator disposed between both electrodes. Type electric double layer capacitor was obtained. A voltage of 3.4 V was applied to the obtained electric double layer capacitor at room temperature for 1 hour at room temperature using a charging / discharging device “HJ201-B” manufactured by Hokuto Denko.
The initial energy density obtained by performing a constant current discharge to 1.0 V at 1.16 mA was 15.1 Wh / l. Similarly, the energy density when 3.8 V is applied is 19.
It was 2 Wh / l. In order to evaluate the long-term operation reliability of the capacitor under voltage application conditions, a voltage of 3.4 V was applied to the capacitor, and after 500 hours, the energy density became 14.5 Wh / l (-4%). There was no decline. The energy density after 500 hours at an applied voltage of 3.8 V is 18.2 Wh / l (−5
%) And hardly changed compared to the initial density.
【００２１】（実施例２）活性炭粉末を石炭ピッチをＫ
ＯＨ賦活して得られたもの（比表面積１５５０ｍ 2 ／
ｇ、平均粒子径１０μｍ）とした以外は実施例１と同様
な電気二重層キャパシターを構成した。活性炭両極中の
リチウム含有量は０．１６重量％であった。３．４Ｖで
充電後の正極側の電位は３．９Ｖ（対Ｌｉ／Ｌｉ+ ）、
負極極側の電位は０．５Ｖ（対Ｌｉ／Ｌｉ+ ）を示し
た。同様に、３．８Ｖで充電した場合、正極の電位は、
４．１Ｖ（対Ｌｉ／Ｌｉ+）、負極極側の電位は０．３
Ｖ（対Ｌｉ／Ｌｉ+ ）を示した。得た電気二重層キャパ
シターの初期のエネルギー密度は、印加電圧３．４Ｖの
場合では１０．５Ｗｈ／ｌ、印加電圧３．８Ｖの場合で
は、１３．４Ｗｈ／ｌを示した。５００時間後のエネル
ギー密度は、印加電圧３．４Ｖの場合では１０．０Ｗｈ
／ｌ（−５％）、印加電圧３．８Ｖの場合では、１２．
５Ｗｈ／ｌ（−７％）を示した。(Example 2) Activated carbon powder was converted to coal pitch K
OH activation (specific surface area 1550m Two/
g, average particle diameter of 10 μm)
A simple electric double layer capacitor was constructed. Activated carbon in both poles
The lithium content was 0.16% by weight. At 3.4V
The potential on the positive electrode side after charging is 3.9 V (vs. Li / Li+),
The potential on the negative electrode side is 0.5 V (vs. Li / Li+)
Was. Similarly, when charged at 3.8 V, the potential of the positive electrode is
4.1 V (vs. Li / Li+), The potential on the negative electrode side is 0.3
V (vs. Li / Li+)showed that. Obtained electric double layer capacity
The initial energy density of the sitter is as follows:
In the case of 10.5 Wh / l and the applied voltage of 3.8 V
Showed 13.4 Wh / l. Enel after 500 hours
The energy density is 10.0 Wh at an applied voltage of 3.4 V.
/ L (-5%) and 3.8V applied voltage, 12.
5 Wh / l (-7%) was shown.
【００２２】（実施例３）活性炭粉末を石炭ピッチをＫ
ＯＨ賦活して得られたもの（比表面積５５０ｍ2／ｇ、
平均粒子径１０μｍ）としたことと、キャパシターの電
解液をトリエチルメチルアンモニウム系電解液とした以
外は実施例１と同様な電気二重層キャパシターを構成し
た。活性炭両極中のリチウム含有量は０．２０重量％で
あった。３．４Ｖで充電後の正極側の電位は３．９Ｖ
（対Ｌｉ／Ｌｉ+ ）、負極極側の電位は０．５Ｖ（対Ｌ
ｉ／Ｌｉ+ ）を示した。同様に、３．８Ｖで充電した場
合、正極の電位は、４．１Ｖ（対Ｌｉ／Ｌｉ+）、負極
極側の電位は０．３Ｖ（対Ｌｉ／Ｌｉ+ ）を示した。得
た電気二重層キャパシターの初期のエネルギー密度は、
印加電圧３．４Ｖの場合では１６．６Ｗｈ／ｌ、印加電
圧３．８Ｖの場合では、２３．３Ｗｈ／ｌを示した。５
００時間後のエネルギー密度は、印加電圧３．４Ｖの場
合では１６．０Ｗｈ／ｌ（−４％）、印加電圧３．８Ｖ
の場合では、２１．５Ｗｈ／ｌ（−８％）を示した。Example 3 Activated carbon powder was converted to coal pitch K
What was obtained by OH activation (specific surface area 550 m 2 / g,
An electric double layer capacitor was formed in the same manner as in Example 1 except that the average particle diameter was 10 μm) and the electrolytic solution of the capacitor was a triethylmethylammonium-based electrolytic solution. The lithium content in both electrodes of the activated carbon was 0.20% by weight. The potential on the positive electrode side after charging at 3.4 V is 3.9 V
(Vs. Li / Li + ), the potential on the negative electrode side is 0.5 V (vs. L
i / Li + ). Similarly, when charged at 3.8 V, the potential of the positive electrode was 4.1 V (vs. Li / Li + ), and the potential of the negative electrode was 0.3 V (vs. Li / Li + ). The initial energy density of the obtained electric double layer capacitor is
In the case of the applied voltage of 3.4 V, 16.6 Wh / l, and in the case of the applied voltage of 3.8 V, 23.3 Wh / l. 5
The energy density after 00 hours was 16.0 Wh / l (-4%) when the applied voltage was 3.4 V, and the applied voltage was 3.8 V
In the case of, 21.5 Wh / l (-8%) was shown.
【００２３】（比較例１）リチウム極と活性炭極の短絡
処理を２８時間行った以外は実施例１と同様な電気二重
層キャパシターを構成した。活性炭両極中のリチウム含
有量は２．３重量％であった。得た電気二重層キャパシ
ターに３．４Ｖ及び３．８Ｖの電圧を印加したところ１
時間以内に電圧降下が起こりエネルギー密度を測定する
ことができなかった。(Comparative Example 1) An electric double layer capacitor similar to that of Example 1 was constructed except that the lithium electrode and the activated carbon electrode were short-circuited for 28 hours. The lithium content in both electrodes of the activated carbon was 2.3% by weight. When voltages of 3.4 V and 3.8 V were applied to the obtained electric double layer capacitor,
A voltage drop occurred within hours, and the energy density could not be measured.
【００２４】（比較例２）リチウム極と活性炭極の短絡
処理を２０秒間行った以外は実施例１と同様な電気二重
層キャパシターを構成した。活性炭両極中のリチウム含
有量は０．００５重量％であった。また、３．４Ｖで充
電後の正極側の電位は、４．５Ｖ（対Ｌｉ／Ｌｉ+ ）、
負極側は１．１Ｖ（対Ｌｉ／Ｌｉ+ ）を示した。３．８
Ｖで充電した場合、正極側は４．６Ｖ（対Ｌｉ／Ｌ
ｉ+ ）、負極側は０．８Ｖを示した。得た電気二重層キ
ャパシターの初期のエネルギー密度は、印加電圧３．４
Ｖの場合では１０．９Ｗｈ／ｌ、印加電圧３．８Ｖの場
合では、１３．７Ｗｈ／ｌを示した。５００時間後のエ
ネルギー密度は、印加電圧３．４Ｖの場合では６．２Ｗ
ｈ／ｌ（−４３％）、印加電圧３．８Ｖの場合では、
６．４Ｗｈ／ｌ（−５３％）を示し、大幅なエネルギー
密度の低下が見られた。(Comparative Example 2) An electric double layer capacitor similar to that of Example 1 was constructed except that the lithium electrode and the activated carbon electrode were short-circuited for 20 seconds. The lithium content in both electrodes of the activated carbon was 0.005% by weight. The potential on the positive electrode side after charging at 3.4 V is 4.5 V (vs. Li / Li + ),
The negative electrode showed 1.1 V (vs. Li / Li + ). 3.8
When charged with V, the positive electrode side is 4.6 V (vs. Li / L)
i + ) and 0.8 V on the negative electrode side. The initial energy density of the obtained electric double layer capacitor was 3.4 applied voltage.
In the case of V, 10.9 Wh / l and in the case of an applied voltage of 3.8 V, 13.7 Wh / l. The energy density after 500 hours is 6.2 W when the applied voltage is 3.4 V.
h / l (-43%) and an applied voltage of 3.8 V,
6.4 Wh / l (-53%), indicating a significant decrease in energy density.
【００２５】（比較例３）リチウム極と活性炭極の短絡
処理を行わない以外は実施例１と同様な電気二重層キャ
パシターを構成した。３．４Ｖで充電後の正極側の電位
は４．６Ｖ（対Ｌｉ／Ｌｉ+ ）、負極側は１．２Ｖ（対
Ｌｉ／Ｌｉ+ ）を示した。得た電気二重層キャパシター
の初期のエネルギー密度は、印加電圧３．４Ｖの場合で
は１０．８Ｗｈ／ｌ、印加電圧３．８Ｖの場合では、１
３．７Ｗｈ／ｌを示した。５００時間後のエネルギー密
度は、印加電圧３．４Ｖの場合では５．５Ｗｈ／ｌ（−
４９％）、印加電圧３．８Ｖの場合では、５．５Ｗｈ／
ｌ（−６０％）を示し、大幅なエネルギー密度の低下が
見られた。Comparative Example 3 An electric double layer capacitor similar to that of Example 1 was constructed except that the short-circuiting process between the lithium electrode and the activated carbon electrode was not performed. After charging at 3.4 V, the potential on the positive electrode side was 4.6 V (vs. Li / Li + ), and the potential on the negative electrode side was 1.2 V (vs. Li / Li + ). The initial energy density of the obtained electric double layer capacitor was 10.8 Wh / l at an applied voltage of 3.4 V, and 1 at a applied voltage of 3.8 V.
3.7 Wh / l was shown. The energy density after 500 hours is 5.5 Wh / l (−) when the applied voltage is 3.4 V.
49%), and 5.5 Wh /
1 (−60%), and a significant decrease in energy density was observed.
【００２６】[0026]
【発明の効果】本発明により、３．３５Ｖ以上の高電圧
をかけることのできる電気二重層キャパシターを提供で
きる。According to the present invention, an electric double layer capacitor capable of applying a high voltage of 3.35 V or more can be provided.
【図１】図１は本発明の実施例１で測定用に用いたコイ
ンセル型キャパシターの模式図である。FIG. 1 is a schematic diagram of a coin cell type capacitor used for measurement in Example 1 of the present invention.
１：ステンレス製容器のケース ２：活性炭成型体 ３：ガスケット ４：セパレータ ５：活性炭成型体 ６：ステンレス製容器の上蓋 1: Case of stainless steel container 2: Activated carbon molded body 3: Gasket 4: Separator 5: Activated carbon molded body 6: Top cover of stainless steel container
Claims (3)
電極を用いた最大許容印加電圧が３．３５Ｖ以上の電気
二重層キャパシターにおいて、活性炭電極両極中に含ま
れるＬｉ量が０．０２重量％以上２重量％以下であるこ
とを特徴とする電気二重層キャパシター。1. In an electric double layer capacitor in which a non-aqueous solution is used as an electrolytic solution and an activated carbon electrode is used for both electrodes and the maximum allowable applied voltage is 3.35 V or more, the amount of Li contained in both electrodes of the activated carbon electrode is 0.02% by weight. % To 2% by weight or less.
した時の該電解液中での正極側の電位がＬｉ／Ｌｉ+ を
対極とした場合、３．５Ｖ以上４．２Ｖ以下であり、か
つ該電解液中での負極側での電位がＬｉ／Ｌｉ+ を対極
とした場合、０．１Ｖ以上０．８Ｖ以下であること特徴
とする請求項１記載の電気二重層キャパシター。2. When the maximum allowable applied voltage is applied to the activated carbon electrode, the potential on the positive electrode side in the electrolyte is 3.5 V or more and 4.2 V or less when Li / Li + is used as a counter electrode; 2. The electric double layer capacitor according to claim 1, wherein the potential on the negative electrode side in the electrolyte is 0.1 V or more and 0.8 V or less when Li / Li + is used as a counter electrode.
項１記載の電気二重層キャパシター。3. The electric double layer capacitor according to claim 1, wherein the amount of Li is 0.2% by weight or more.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30191397A JP3812098B2 (en) | 1997-11-04 | 1997-11-04 | Electric double layer capacitor |
| EP98112660A EP0890963A3 (en) | 1997-07-09 | 1998-07-08 | Electric double-layer capacitor |
| US09/111,765 US6094338A (en) | 1997-07-09 | 1998-07-08 | Electric double-layer capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP30191397A JP3812098B2 (en) | 1997-11-04 | 1997-11-04 | Electric double layer capacitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11145009A true JPH11145009A (en) | 1999-05-28 |
| JP3812098B2 JP3812098B2 (en) | 2006-08-23 |
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ID=17902628
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| Application Number | Title | Priority Date | Filing Date |
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005057597A1 (en) * | 2003-12-10 | 2005-06-23 | Eamex Corporation | Electricity storage device and process for producing the same |
| JP2006351889A (en) * | 2005-06-17 | 2006-12-28 | Mitsubishi Electric Corp | Electric double layer capacitor |
| JP2007324271A (en) * | 2006-05-31 | 2007-12-13 | Matsushita Electric Ind Co Ltd | Electrochemical capacitor and its manufacturing method |
| JP2008117891A (en) * | 2006-11-02 | 2008-05-22 | Matsushita Electric Ind Co Ltd | Electrochemical energy accumulation device |
| JP2008258213A (en) * | 2007-03-30 | 2008-10-23 | Nippon Chemicon Corp | Manufacturing method of electrode for electric double-layer capacitor |
| JP2009158532A (en) * | 2007-12-25 | 2009-07-16 | Mazda Motor Corp | Carbonaceous electrode material and electric storage device using the same |
| JP2010050125A (en) * | 2008-08-19 | 2010-03-04 | Otsuka Chem Co Ltd | Electric double layer capacitor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8784764B2 (en) * | 2008-12-15 | 2014-07-22 | Corning Incorporated | Methods for forming activated carbon material for high energy density ultracapacitors |
-
1997
- 1997-11-04 JP JP30191397A patent/JP3812098B2/en not_active Expired - Fee Related
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2005057597A1 (en) * | 2003-12-10 | 2005-06-23 | Eamex Corporation | Electricity storage device and process for producing the same |
| JP2006351889A (en) * | 2005-06-17 | 2006-12-28 | Mitsubishi Electric Corp | Electric double layer capacitor |
| JP4593379B2 (en) * | 2005-06-17 | 2010-12-08 | 三菱電機株式会社 | Electric double layer capacitor |
| JP2007324271A (en) * | 2006-05-31 | 2007-12-13 | Matsushita Electric Ind Co Ltd | Electrochemical capacitor and its manufacturing method |
| JP2008117891A (en) * | 2006-11-02 | 2008-05-22 | Matsushita Electric Ind Co Ltd | Electrochemical energy accumulation device |
| JP2008258213A (en) * | 2007-03-30 | 2008-10-23 | Nippon Chemicon Corp | Manufacturing method of electrode for electric double-layer capacitor |
| JP2009158532A (en) * | 2007-12-25 | 2009-07-16 | Mazda Motor Corp | Carbonaceous electrode material and electric storage device using the same |
| JP2010050125A (en) * | 2008-08-19 | 2010-03-04 | Otsuka Chem Co Ltd | Electric double layer capacitor |
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| Publication number | Publication date |
|---|---|
| JP3812098B2 (en) | 2006-08-23 |
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