JPH0413831B2

JPH0413831B2 -

Info

Publication number: JPH0413831B2
Application number: JP61169903A
Authority: JP
Inventors: Kenichiro Jinnai
Original assignee: Meidensha Electric Manufacturing Co Ltd
Current assignee: Meidensha Electric Manufacturing Co Ltd
Priority date: 1986-07-21
Filing date: 1986-07-21
Publication date: 1992-03-10
Also published as: JPS6326966A

Description

[Detailed description of the invention]

Ａ産業上の利用分野この発明は、電解液循環形亜鉛−臭素電池の運
転方法に関し、とくに負極電極上に析出する亜鉛
デンドライトの抑制に効果の大きいデントライト
の抑制剤を使用した運転方法に関するものであ
る。Ｂ発明の概要この発明は、亜鉛−臭素電池の負極表面に電析
して電池効率を低下させる亜鉛のデンドライト抑
制法に効果ある電池の運転方法として、通常の基
準電解液に、鉛（以下Pbとする）、スズ（以下Sn
とする）、インジウム（以下Inとする）及びタリ
ウム（以下Tlとする）のうちの２種の金属イオ
ンを含む無機溶液と、メチルドテシルモルホリニ
ウムブロマイド（以下MDMBとする）の有機溶
液との混合溶液を添加した複合電解液を用い、放
電終止電圧を1.0V／セルと設定して、放電後の
電極電圧が１セル当たり1.0Vになると直ちに充
電操作に移る連続運転方法を提供するものであ
る。Ｃ従来の技術第５図は良く知られている亜鉛−臭素電池の構
成説明図である。図において、１は電池反応槽
（１セル分）、２は正極室、３は負極室、４は隔膜
（セパレータ）、５は正極、６は負極、７は正極電
解液、８は負極電解液、９及び１０はそれぞれ正
極及び負極側の電解液タンク、１１及び１２はそ
れぞれ正極及び負極側の循環用ポンプである。上記の亜鉛−臭素電池において、前記亜鉛デン
ドライトの抑制を目的として、負極電解液８にデ
ンドライト抑制剤を添加した例は、発明者による
特願昭60−44899号に記載された亜鉛−臭素電池
の電解液がある。しかし、亜鉛デンドライト抑制
を主眼として、これに基づく亜鉛−臭素電池の運
転方法を提供した従来の技術はない。Ｄ発明の解決しようとする問題点上記の亜鉛−臭素電池における通常運転におい
ては、負極電極表面に亜鉛の電析及び溶解反応が
行われる。ここでの亜鉛電析はデンドライト析出
し易く、これが電池効率を低下させる一因となつ
ている。この問題は放電終了後（通常1.0V／セ
ルになつた時）に直ちに充電を行うような連続サ
イクルにおいて顕著である。このデンドライト成長を抑制する手段として
は、これまで、放電後一度電極に残留している亜
鉛をすべて溶解してしまうために完全放電という
処理を行つてから次の充電を行うことが必要であ
る。この完全放電は通常２〜３時間を要するもの
であり、またこの時間中ポンプは作動しているた
めに、これは電池のエネルギー損失につながるも
のである。このような処理工程をとらねばならな
いことは電池運動のモードを複雑化し、さらに補
器を含めた全体のエネルギー効率も低下させてい
ることが問題点とされている。とくに、電力貯蔵用電池としての場合は、月曜
日〜金曜日の間すなわち１日１サイクルで最低５
サイクルの連続運転が望まれている。さらに、電
気自動車用にいたつては、上記完全放電を必要と
する運転方法はその目的性質上非常に不利なもの
であり、完全な解決策を要望されていた問題であ
る。Ｅ問題点を解決するための手段この発明は上記問題点を解決するためになされ
たもので、亜鉛−臭素電池の基準電解液に、Pb、
Sn、In及びTlのうちの２種の金属イオンを実験
でえられた最適濃度を含む無機質溶液とMDMB
を最適濃度含む有機質溶液の混合液をデンドライ
ト抑制剤として添加した複合電解液を用い、運転
に当つて、放電終止電圧を1.0V／セルに設定し
て、上記の完全放電を含まない充放電操作を上記
デンドライト抑制剤を用いて可能にする電池運転
方法である。Ｆ作用この発明においては、亜鉛のデンドライト抑制
剤を上記のように特定の無機質と有機質溶剤を混
合して複合化したので、従来のように完全放電を
用いることなく、比較的高い所定の放電終止電圧
を設定して充電に移る操作を行うことができ、電
池の連続運転性能を高め得るものである。このデ
ンドライト抑制剤に用いる各成分元素や物質はデ
ンドライト抑制において下記の機能をもつ。すな
わち Pb及びTlは、亜鉛（以下Znとする）と共析
するため均一電着性を促進する。 Sn及びInは、Znと共析するとともに、充電
時に生成される酸化物を還元（例えば、Snの
場合、Sn²⁺→Sn⁴⁺のように）することにより
均一な放電表面を形成させるので、放電後の電
着性が向上する。 MDMBは析出物に吸着し小さな析出物又は
その種をまぶす作用をもち、デンドライトの生
長を抑制する。そして均一な溶解表面をつくり
出すのに役立つ。このため放電後の電着性が向
上する。以上３つの機能が複合化によつてさらに相乗効
果を生み、総合的に優れたデンドライト抑制を達
成せしめる。上記の効果を説明するために、第１図に従来と
本発明による場合の充放電の連続運転パターンを
グラフによつて比較して示した。第１図ａは従来
の運転方法によるパターンで、第１図ｂは完全放
電によらない新しいパターンを示す。図の横軸は
充放電時間、縦軸はセル電圧である。第１図において、従来はａのようにデンドライ
ト抑制を完全にするため、前述の完全放電操作を
必要としたが、本発明の複合デンドライト抑制剤
を使用することによつて、ｂに示したパターンの
ように放電でセル電圧が1.0Vの放電終止電圧に
達したとき、ただちに充電に移行する通常方法に
おいても、デンドライト抑制が効率よく達成され
て、正常な充放電のサイクル数の性能向上が得ら
れる。なお、このような完全放電を用いない場合
を、無完全放電と呼んでいる。Ｇ発明の実施例以下、この発明による亜鉛−臭素電池の運転方
法に関して検討実験を行つた結果を下記実施例及
び比較例によつて説明する。実験はすべて電極面
積800cm²の10積層電池によつて行い、充放電電流
密度はｉ＝20ｍＡ／cm²である。実験条件としてお
もにデンドライト抑制剤の組成（濃度を含む）を
かえた試料11種類を、添加した基準の電解液の組
成及び濃度とともに第１表に示した。また、第１
表には、デンドライト抑制剤の種類別に試料番号
１〜11を番号付けして示した。 A. Industrial Application Field This invention relates to a method of operating a circulating electrolyte zinc-bromine battery, and in particular to a method of operating a zinc-bromine battery using a dendrite inhibitor that is highly effective in suppressing zinc dendrites deposited on the negative electrode. It is. B. Summary of the Invention This invention provides a battery operating method that is effective in suppressing zinc dendrites, which are electrodeposited on the negative electrode surface of zinc-bromine batteries and reduce battery efficiency. ), tin (hereinafter referred to as Sn
), an inorganic solution containing two metal ions of indium (hereinafter referred to as In) and thallium (hereinafter referred to as Tl), and an organic solution of methyldotecylmorpholinium bromide (hereinafter referred to as MDMB). Provides a continuous operation method that uses a composite electrolyte to which a mixed solution of is added, sets the discharge end voltage to 1.0V/cell, and immediately starts charging operation when the electrode voltage after discharge reaches 1.0V per cell. It is. C. Prior Art FIG. 5 is an explanatory diagram of the configuration of a well-known zinc-bromine battery. In the figure, 1 is a battery reaction tank (one cell), 2 is a positive electrode chamber, 3 is a negative electrode chamber, 4 is a diaphragm (separator), 5 is a positive electrode, 6 is a negative electrode, 7 is a positive electrode electrolyte, and 8 is a negative electrode electrolyte. , 9 and 10 are electrolyte tanks on the positive and negative electrode sides, respectively, and 11 and 12 are circulation pumps on the positive and negative electrode sides, respectively. In the above zinc-bromine battery, an example in which a dendrite inhibitor is added to the negative electrode electrolyte 8 for the purpose of suppressing the formation of zinc dendrites is an example of the zinc-bromine battery described in Japanese Patent Application No. 44899/1989 by the inventor. There is an electrolyte. However, there is no prior art that provides a method for operating a zinc-bromine battery based on the suppression of zinc dendrites. D Problems to be Solved by the Invention During normal operation of the zinc-bromine battery described above, zinc electrodeposition and dissolution reactions occur on the surface of the negative electrode. Zinc electrodeposition here tends to cause dendrite precipitation, which is one of the causes of lowering battery efficiency. This problem is most noticeable in continuous cycles where charging is performed immediately after discharging (usually when the voltage reaches 1.0 V/cell). As a means of suppressing this dendrite growth, it has been necessary to perform a complete discharge process to dissolve all the zinc remaining on the electrode after discharge, and then perform the next charge. This complete discharge usually takes 2 to 3 hours, and since the pump is running during this time, this results in a loss of energy in the battery. The problem is that the necessity of such processing steps complicates the mode of battery movement and further reduces the overall energy efficiency including auxiliary devices. In particular, when used as an energy storage battery, at least 5
Continuous operation of the cycle is desired. Furthermore, when it comes to electric vehicles, the driving method that requires complete discharge is extremely disadvantageous due to its purpose, and a complete solution has been desired. E. Means for Solving the Problems This invention was made to solve the above problems, and includes Pb, Pb, and
An inorganic solution containing two metal ions of Sn, In, and Tl at the optimum concentration obtained experimentally and MDMB.
Using a composite electrolyte containing a mixture of organic solutions containing the optimum concentration as a dendrite inhibitor, the final discharge voltage was set to 1.0 V/cell during operation, and the charge/discharge operation without complete discharge was performed as described above. This is a battery operation method that enables the use of the above-mentioned dendrite inhibitor. F Effect In this invention, since the zinc dendrite inhibitor is compounded by mixing a specific inorganic substance and an organic solvent as described above, a relatively high predetermined discharge termination can be achieved without using a complete discharge as in the conventional case. The battery can be operated to set the voltage and start charging, which can improve the continuous operation performance of the battery. Each component element or substance used in this dendrite inhibitor has the following functions in dendrite inhibition. That is, Pb and Tl promote uniform electrodeposition because they co-deposit with zinc (hereinafter referred to as Zn). Sn and In form a uniform discharge surface by eutectoiding with Zn and reducing the oxides generated during charging (for example, Sn ²⁺ → Sn ⁴⁺ in the case of Sn). , the electrodeposition after discharge is improved. MDMB has the effect of adsorbing to precipitates and scattering small precipitates or their seeds, thereby suppressing the growth of dendrites. and helps create a uniform melting surface. Therefore, the electrodepositability after discharge is improved. By combining the above three functions, a synergistic effect is produced, and comprehensively excellent dendrite suppression can be achieved. In order to explain the above effects, FIG. 1 graphically compares the continuous charging/discharging operation patterns of the conventional case and the present invention. FIG. 1a shows a pattern based on the conventional operating method, and FIG. 1b shows a new pattern that does not involve complete discharge. The horizontal axis of the figure is charge/discharge time, and the vertical axis is cell voltage. In FIG. 1, in order to completely suppress dendrites as shown in a, the above-mentioned complete discharge operation was required in the past, but by using the composite dendrite suppressant of the present invention, the pattern shown in b is obtained. Even with the normal method of immediately transitioning to charging when the cell voltage reaches the end-of-discharge voltage of 1.0V during discharging, dendrite suppression is efficiently achieved and the performance of the number of normal charge/discharge cycles is improved. It will be done. Note that the case where such complete discharge is not used is called non-complete discharge. G Examples of the Invention Hereinafter, the results of experiments conducted regarding the operating method of the zinc-bromine battery according to the present invention will be explained with reference to the following examples and comparative examples. All experiments were conducted using a 10-layer battery with an electrode area of 800 cm ² and a charging/discharging current density of i=20 mA/cm ² . Table 1 shows 11 types of samples in which the composition (including concentration) of the dendrite inhibitor was changed as experimental conditions, along with the composition and concentration of the standard electrolyte solution added. Also, the first
In the table, sample numbers 1 to 11 are numbered and shown according to the type of dendrite inhibitor.

【表】比較例１第２図は、第１表に示した試料No.１（無添加）
及びNo.２（Pb：１×10^-4）のサイクル充放電の挙
動を示すグラフである。図において、横軸は充放
電時間、縦軸はセル電圧である。無添加（No.１の
試料、グラフは実線）のものは、２サイクル目
で、図にみられるように、放電末期の電位が緩慢
になり約2Vの段がみられ、効率が低下した。こ
の場合、運転を中止し、放電終了後電池を解体し
て観察した結果、膜にかなりのデンドライト状亜
鉛が付着していた。一方Pbを１×10^-4mol／添
加（No.２の試料、グラフは点線）したものは、３
サイクル目で無添加のものと同様な結果がみられ
た。この場合、３サイクル目放電終了後、完全放
電を行い再度充放電を行つたが、電池効率は回復
しなかつた。比較例２ここで、試料No.３に示したPbを１×10^-4及び
Snを１×10^-3mol／添加したものは10サイクル
まで電池効率の低下がみられなかつたが、11サイ
クル目で比較例１と同様の結果を示した。実施例１第３図は第１表に示すNo.４の試料すなわちPb1
×10^-4mol／、Sn1×10^-3mol／及び
MDMB1.5×10^-3mol／をデンドライト抑制剤
として添加した複合電解液によるサイクル充放電
のサイクル数と電池効率の関係グラフである。図
の横軸はサイクル数、縦軸は効率である。図にお
いて、白丸印の曲線はクーロン（電流）効率で
Ceffで表し、半白丸印の曲線は電圧効率Veff、
黒丸印の曲線はエネルギー効率Eeffである。図か
ら明らかなように、この試料によるものでは、80
サイクルまで電池効率の低下がみられず、連続充
放電が可能である特性を示した。図示したように
84サイクル目で効率低下をみたが、この時点で完
全放電操作を行つた結果効率は回復した。すなわ
ち、上記比較例１及び２の系よりも電池の損傷が
少なかつたと判断される。図示は省略したが、以
後150サイクルまで効率の低下はみられず、その
後も連続運転中である。なお、第１表の試料No.５及び６を除く試料No.
７、No.８、No.９、No.10及びNo.11について、同様の
実験を行つた結果を第２表にまとめて示した。[Table] Comparative Example 1 Figure 2 shows sample No. 1 (no additives) shown in Table 1.
and No. 2 (Pb: 1×10 ^-4 ) is a graph showing the behavior of cycle charging and discharging. In the figure, the horizontal axis is charge/discharge time, and the vertical axis is cell voltage. In the case of the sample without additives (sample No. 1, solid line in the graph), in the second cycle, as seen in the figure, the potential at the end of discharge slowed down to a level of about 2 V, and the efficiency decreased. In this case, operation was stopped, the battery was disassembled after discharging, and observation revealed that a considerable amount of dendrite-like zinc had adhered to the membrane. On the other hand, the sample to which 1×10 ^-4 mol/Pb was added (sample No. 2, the graph is a dotted line) had a concentration of 3
Results similar to those without additives were observed in the second cycle. In this case, after the third cycle of discharge was completed, the battery was completely discharged and charged and discharged again, but the battery efficiency did not recover. Comparative Example 2 Here, Pb shown in sample No. 3 was added to 1×10 ^-4 and
In the case where 1×10 ^-3 mol/Sn was added, no decrease in battery efficiency was observed up to the 10th cycle, but the same results as Comparative Example 1 were obtained at the 11th cycle. Example 1 Figure 3 shows sample No. 4 shown in Table 1, that is, Pb1.
×10 ^-4 mol/, Sn1×10 ^-3 mol/ and
It is a graph showing the relationship between the number of cycles of charging and discharging and battery efficiency using a composite electrolytic solution containing 1.5×10 ⁻³ mol/MDMB as a dendrite inhibitor. The horizontal axis of the figure is the number of cycles, and the vertical axis is efficiency. In the figure, the curve marked with a white circle is the coulomb (current) efficiency.
It is expressed as Ceff, and the curve marked with a half-white circle is the voltage efficiency Veff,
The curve marked with a black circle is the energy efficiency Eeff. As is clear from the figure, for this sample, 80
There was no decrease in battery efficiency until cycle time, and the battery exhibited characteristics that allowed continuous charging and discharging. as shown
Efficiency decreased at the 84th cycle, but as a result of performing a complete discharge operation at this point, efficiency was restored. That is, it is judged that the battery was less damaged than the systems of Comparative Examples 1 and 2 above. Although not shown in the figure, no decrease in efficiency was observed up to 150 cycles, and the system continued to operate continuously thereafter. In addition, sample No. except for sample No. 5 and 6 in Table 1.
Similar experiments were conducted on Samples No. 7, No. 8, No. 9, No. 10, and No. 11, and the results are summarized in Table 2.

【表】＊最終サイクル〓完全放電なしで効率低下
のなかつたサイクル数
第２表にみられるように、試料No.７、８、及び
９のように金属元素２種にMDMBを添加したも
のは、No.４の試料と同様に非常に良い結果を得
た。これに対して、No.10及び11のように無機系だ
けのデンドライト抑制剤では、サイクル数が約３
であり著しく小さいことがわかり、連続運転に使
用できないことになる。また無機系のみのものは
組合せによつては無添加（No.１の試料）のものと
同等のものがあつた。したがつて、本電池の連続
運転には、いずれの場合もMDMBの添加が必要
であることが重要な鍵となる。実施例２ここでは、放電終止電圧を0V／セル、1.0V／
セル及び1.5V／セルと設定して、連続運転時の
効率を調べた。第４図は実施例１のデンドライト
抑制剤を用いた系での放電終止電圧と効率の関係
グラフである。図において、横軸は放電終止電
圧、縦軸は効率であり、第３図と同様にクーロン
効率Ceff、電圧効率Veff及びエネルギー効率Eeff
を示した。図に示されるように、電圧効率は各電
圧ともほとんど差がみられないが、クーロン効率
はOVで著しく低下している。これは電池電圧が
低くなると、残留亜鉛量が減少し、臭素の酸化反
応がおこりやすくなるためである。このため、放
電末期に負極中の臭素濃度が増加し、次の充電時
に自己放電が増えてクーロン効率が低下するもの
である。また、1.5Vとした場合は残留亜鉛が多
いため、クーロン効率は増加するが、サイクル寿
命が短くなつている。したがつて放電終止電圧は
1V／セルが最も効率が高く連続サイクル数も多
いことがわかり、この電圧を連続運転の放電終止
電圧に設定することとした。Ｈ発明の効果この発明は以上説明したとおり、デンドライト
抑制剤を複合化して放電終止電圧を1.0V／セル
に設定したことにより、完全放電を用いない運転
で80サイクルの充放電が達成された。これによつ
て、従来から実施されていた完全放電を用いたデ
ンドライト抑制法を用いない充放電サイクルが可
能となり、完全放電の時間を省略することによる
エネギー損失を防止し、かつ全体のエネルギー効
率を高めることができる効果がある。また、放電終止電圧を１セル当り1.0Vに設定
して連続運転することにより、放電末期の負極上
の臭素発生を抑えることができ、また残留亜鉛が
次の放電においても活用されクーロン効率の増大
が得られる効果がある。[Table] * Final cycle = Number of cycles without complete discharge and no efficiency decrease As with sample No. 4, very good results were obtained. On the other hand, with inorganic-only dendrite inhibitors such as Nos. 10 and 11, the number of cycles is approximately 3.
It turns out that it is extremely small and cannot be used for continuous operation. Also, depending on the combination of inorganic-only products, there were some that were equivalent to additive-free products (sample No. 1). Therefore, the key to continuous operation of this battery is that MDMB must be added in any case. Example 2 Here, the discharge end voltage is set to 0V/cell and 1.0V/cell.
The efficiency during continuous operation was investigated by setting the cell and 1.5V/cell. FIG. 4 is a graph showing the relationship between discharge end voltage and efficiency in a system using the dendrite inhibitor of Example 1. In the figure, the horizontal axis is the end-of-discharge voltage, and the vertical axis is the efficiency. As in Figure 3, the coulomb efficiency Ceff, voltage efficiency Veff, and energy efficiency Eeff
showed that. As shown in the figure, there is almost no difference in voltage efficiency at each voltage, but Coulomb efficiency decreases significantly at OV. This is because as the battery voltage decreases, the amount of residual zinc decreases, making it easier for the bromine oxidation reaction to occur. For this reason, the bromine concentration in the negative electrode increases at the end of discharge, and self-discharge increases during the next charge, resulting in a decrease in coulombic efficiency. Furthermore, when the voltage is set to 1.5V, there is a large amount of residual zinc, so although the coulombic efficiency increases, the cycle life is shortened. Therefore, the discharge end voltage is
It was found that 1V/cell had the highest efficiency and the highest number of continuous cycles, so we decided to set this voltage as the discharge end voltage for continuous operation. H. Effects of the Invention As explained above, in this invention, by combining a dendrite inhibitor and setting the discharge end voltage to 1.0 V/cell, 80 cycles of charging and discharging were achieved in an operation without complete discharge. This makes it possible to perform charge/discharge cycles without using the conventional dendrite suppression method that uses complete discharge, prevents energy loss due to omitting the complete discharge time, and improves overall energy efficiency. There are effects that can be enhanced. In addition, by setting the discharge end voltage to 1.0V per cell and operating continuously, it is possible to suppress the generation of bromine on the negative electrode at the end of discharge, and the remaining zinc is utilized in the next discharge, increasing Coulombic efficiency. There is an effect that can be obtained.

[Brief explanation of drawings]

第１図はこの発明を構成する連続運転サイクル
の充放電パターンを示す特性グラフ、第２図はデ
ンドライト抑制不十分の場合のサイクル充放電の
挙動を示す特性グラフ、第３図は本発明の一実施
例の特性を示す連続充放電のサイクル−効率特性
図、第４図は本発明の一実施例による放電終止電
圧−効率特性図、第５図は従来の亜鉛−臭素電池
の構成説明図である。 Fig. 1 is a characteristic graph showing the charging/discharging pattern of the continuous operation cycle constituting this invention, Fig. 2 is a characteristic graph showing the behavior of cycle charging/discharging when dendrite suppression is insufficient, and Fig. 3 is a characteristic graph showing the charging/discharging pattern of the continuous operation cycle constituting the present invention. FIG. 4 is a continuous charge/discharge cycle-efficiency characteristic diagram showing the characteristics of the embodiment. FIG. 4 is an end-of-discharge voltage-efficiency characteristic diagram according to an embodiment of the present invention. FIG. 5 is an explanatory diagram of the configuration of a conventional zinc-bromine battery. be.

Claims

[Scope of Claims] 1. Zinc made by using electrode plates made of carbon plastic consisting of polyethylene in a mixing ratio of 60 to 80% by weight and carbon black in a range of 20 to 40% by weight for the positive and negative electrodes. - In a method for operating a bromine battery, two elements selected from the metal elements lead, tin, indium, and thallium are added to an electrolytic solution consisting of a mixed solution of ZnBr ₂ , a bromine complexing agent, and a conductivity improver _NH 4 Cl. An inorganic solution with an ion concentration range of 5×10 ^-5 to 1×10 ^-3 mol/of each of the above elements, and an inorganic solution with a concentration range of 1×10 ^-3 to 3×10 ^-3 mol/
A composite electrolyte containing an organic solution of methyldodecylmorpholinium bromide and a dendrite inhibitor added thereto was used, and the final discharge voltage was set to 1.
1. A method of operating a zinc-bromine battery, which comprises repeatedly and continuously performing an operation of setting the voltage to 1.0 V per cell and immediately starting charging when the discharge end voltage is reached after the start of discharging. 2 The dendride inhibitor has a concentration of 1×
The method according to claim 1, which is a mixed solution of 10 ^-4 mol/lead, 1 x 10 ^-3 mol/tin, and 1.5 x 10 ^-3 mol/methyldodecylmorpholinium bromide. how to drive. 3 The dendrite inhibitor has a concentration of 1×
The operating method according to claim 1, which is a mixed solution of lead at a concentration of 10 ^-4 mol/, indium at a concentration of 1 x 10 ^-3 mol/, and methyldodecylmorpholinium bromide at a concentration of 1.5 x 10 ^-3 mol/. . 4 The dendrite inhibitor has a concentration of 1×
10 ^-4 mol/thallium and concentration 1×10 ^-3 mol/
The operating method according to claim 1, which is a mixed solution of tin and methyldodecylmorpholinium bromide at a concentration of 1.5×10 ^-3 mol/. 5 The dendrite inhibitor has a concentration of 1×
10 ^-4 mol/thallium and concentration 1×10 ^-3 mol/
2. The operating method according to claim ¹ , wherein the mixed solution is indium of 6 The concentration of each metal element used in the dendrite inhibitor is 5×10 ^-5 to 1× lead and thallium.
10 ^-4 mol/, tin and indium 5 x 10 ^-5 ~
The operating method according to claim 1, wherein the amount is in the range of 1×10 ^-3 mol/.