JP6160087B2 - battery - Google Patents

Description

  The present invention relates to a battery, and more particularly to a battery that charges and discharges by circulating an aqueous electrolyte.

A redox flow battery, which is a kind of the above, is a method in which an active material dissolved in an electrolytic solution is advanced by circulation of the solution. Vanadium-based, ZnBr, ZnCr batteries and the like have been put into practical use. Among these, vanadium-based batteries have characteristics such as high cycle characteristics, but the raw materials are scarce and it is desired to use raw materials that are more abundant. Although the ZnBr battery has relatively abundant raw material resources in nature, there is a problem of dendrite generation at the Zn electrode, and in order to prevent this, an operation of periodically performing full discharge is necessary. A battery using sulfide ions such as sodium sulfide as an active material has abundant raw material resources in nature, and is promising in terms of ease of manufacture and cost reduction. As a system using sulfide ions as a negative electrode active material, a sodium sulfide-bromine battery has been studied as a demonstration plant. There are also reports of flow batteries combined with sodium ferrocyanide cathodes. On the other hand, a battery using sulfide ions as a positive electrode active material and using, for example, a zinc electrode as a negative electrode is a promising battery system such as abundant raw material resources and cost reduction.

When a battery using an aqueous electrolyte solution in which a water-soluble sulfide such as sodium sulfide is dissolved as an active material is charged and discharged, a high voltage is applied in a high oxidation state (low reduction state) of Na ₂ S ₄ or higher, and Na ₂ S ₃ − A two-stage discharge characteristic is exhibited depending on the oxidation state of sulfur, that is, a low voltage in the low oxidation state (high reduction state) of Na ₂ S. Among them, there is a problem that very large polarization occurs in charge and discharge in a low oxidation state, and energy efficiency of charge and discharge is lowered. For example, on the other hand, what reduces overvoltage by carrying | supporting cobalt on carbon as a catalyst is proposed (for example, refer nonpatent literature 1).

Electrochemica Acta, 51, 6304 (2006)

  However, in the battery of Non-Patent Document 1 described above, there is a point in using a catalyst containing cobalt, which is limited in terms of resources, and a manufacturing complexity that a catalyst must be prepared and added. Therefore, there has been a demand for higher energy efficiency by a relatively easy method.

  This invention is made | formed in view of such a subject, and it aims at providing the battery which can improve energy efficiency more in the thing using an aqueous electrolyte solution.

  As a result of diligent research to achieve the above-mentioned object, the present inventors have added a water-soluble organic substance having a carbonyl group in the molecule to the aqueous electrolyte solution. It has been found that energy efficiency can be improved, and the present invention has been completed.

That is, the battery of the present invention is
A positive electrode;
A negative electrode,
An aqueous electrolyte solution in which a sulfur compound that is an active material and a water-soluble compound that is at least one of aldehydes, ketones, and amides are dissolved;
It is equipped with.

  The battery of the present invention can further increase energy efficiency. The reason why such an effect is obtained is not clear, but is presumed as follows. For example, some interaction is expressed, such as forming a complex between a water-soluble compound having a carbonyl group in the molecule and a sulfur compound, which is an active material present in an aqueous solution, and thereby, on the electrode It is inferred that charge exchange occurs easily. For this reason, it is guessed that the voltage drop at the time of sulfur reduction | restoration is suppressed more, and energy efficiency improves more.

FIG. 3 is an explanatory diagram showing an outline of the configuration of the redox flow battery 10. The charging / discharging measurement result of Examples 1-4 and Comparative Examples 1 and 2. FIG. Explanatory drawing showing the relationship between the density | concentration of DMF, and the voltage difference of a charge voltage and a discharge voltage. The charging / discharging measurement result of Examples 5-7 and Comparative Examples 1 and 3. FIG.

  The battery of the present invention includes a positive electrode, a negative electrode, and an aqueous electrolyte. This aqueous electrolyte solution dissolves a sulfur compound that is an active material and a water-soluble compound that is at least one of aldehydes, ketones, and amides. The battery of the present invention may be a redox flow battery using an electrolytic solution for the positive electrode and the negative electrode. The battery includes, for example, a separator that separates the case into a positive electrode chamber and a negative electrode chamber, and a liquid feeding unit connected to the positive electrode chamber, and the aqueous electrolyte is accommodated in the positive electrode chamber in contact with the positive electrode. The liquid may be distributed by the liquid feeding unit. Further, the aqueous electrolyte solution may be accommodated in the negative electrode chamber in contact with the negative electrode and distributed through the liquid feeding unit. Here, the positive electrode and the negative electrode are determined by the potential difference between the two types of electrodes. If the electrode using the aqueous electrolyte of the present invention has a noble potential with respect to the counter electrode, the positive electrode, and if the electrode has a base potential, the negative electrode It becomes. For example, the former example is a zinc-sodium sulfide battery, and the latter example is a sodium sulfide-bromine battery. Hereinafter, the redox flow battery will be specifically described.

In the battery of the present invention, the aqueous electrolyte solution dissolves a sulfur compound that is an active material and a water-soluble compound that is at least one of aldehydes, ketones, and amides. The water-soluble compound preferably has, for example, at least one of an aldehyde structure, a ketone structure, and an amide structure, of which a ketone structure or an amide structure is included. More preferably. This water-soluble compound may be a compound represented by the general formula, R ¹ —C (═O) —R ² . However, R ^1, R ² are each optionally functional group be different even in the same, hydrogen, is any one or more of the hydrocarbon group and -NR ³ R ^4. R ³ and R ⁴ may be the same as or different from each other, and may be the same as or different from any one of R ¹ and R ^2. Any one or more. The hydrocarbon group may be a straight chain, and may have a branched chain or a substituent. Moreover, as a hydrocarbon group, when the solubility to water is considered, it is preferable that it is C3 or less, and 2 or less is more preferable. The hydrocarbon group is preferably a saturated hydrocarbon group (alkyl group), and examples thereof include a methyl group, an ethyl group, and a propyl group. In addition, as a structure that improves water solubility even when the number of carbon atoms is larger, a substituent connected by an ether bond, for example, an ethylene glycol structure can be used, and this structure is preferable from the viewpoint of non-volatility and ensuring stability. . Among water-soluble compounds, examples of aldehydes include saccharides such as glucose in addition to formaldehyde and acetaldehyde. For example, since glucose has a structure having an aldehyde group as a chain in an equilibrium state, this glucose is suitable from the viewpoint that it is effective, nonvolatile and stable for a long period of time.
Examples of ketones include acetone and diethyl ketone. Of these, acetone is preferred. Examples of amides include dimethylformamide (DMF) and diethylformamide. Among these, dimethylformamide is preferable.

  In the battery of the present invention, the amount of water-soluble compound dissolved in the aqueous electrolyte is not particularly limited, but is preferably in the range of 10% by volume or more, and 15% by volume or more with respect to the aqueous electrolyte. Is more preferable. When the water-soluble compound dissolved in the aqueous electrolyte is dimethylformamide (DMF), the amount of DMF dissolved is preferably 15% by volume or more, more preferably 20% by volume or more with respect to the aqueous electrolyte. In this range, energy efficiency can be further increased. The amount of DMF dissolved is preferably 50% by volume or less with respect to the aqueous electrolyte. Within this range, the decrease in conductivity can be further suppressed, which is preferable. When the water-soluble compound dissolved in the aqueous electrolyte is acetone, the amount of acetone dissolved is preferably 10% by volume or more, more preferably 15% by volume or more with respect to the aqueous electrolyte. If it is 10 volume% or more, energy efficiency can be improved more. The amount of acetone dissolved is preferably 30% by volume or less, more preferably 20% by volume or less, based on the aqueous electrolyte. When it is 30% by volume or less, two-layer separation between water and acetone can be further suppressed, which is preferable. When the water-soluble compound dissolved in the aqueous electrolyte is glucose, the amount of glucose dissolved is preferably 10% by mass or more, more preferably 15% by mass or more based on the aqueous electrolyte. In this range, energy efficiency can be further increased. Moreover, as this dissolution amount, it is preferable that it is 50 mass% or less. In this range, the decrease in conductivity can be further suppressed.

  In the battery of the present invention, the sulfur compound as an active material dissolved in the aqueous electrolyte is preferably, for example, one or more of an alkali metal sulfide and an alkali metal polysulfide. Examples of the alkali metal sulfide include one or more of sodium sulfide, lithium sulfide, potassium sulfide, and the like. Examples of the alkali metal polysulfide include one or more of sodium polysulfide, lithium polysulfide, and potassium polysulfide. Of these, a sulfide containing sodium is more preferable. This sulfur compound is water-soluble, but it is not necessary that all of the sulfur compound is dissolved in the aqueous electrolyte solution, and it can also be used in a partially precipitated state in a saturated state. The amount of the sulfur compound contained in the aqueous electrolyte is, for example, preferably in the range of 1% by mass to 20% by mass and more preferably in the range of 5% by mass to 15% by mass with respect to the aqueous solution. preferable.

  In the battery of the present invention, the aqueous electrolyte is preferably neutral and alkaline, and may dissolve an alkaline solution such as sodium hydroxide or potassium hydroxide, or the pH may be neutral using a buffer solution. The alkali range may be controlled. It is not preferable that the aqueous electrolyte is acidic because generation of hydrogen sulfide is a concern. The aqueous electrolyte solution preferably has a pH of 9 or more. The aqueous electrolyte is preferably an alkali hydroxide solution of 0.1 N or more and 4 N or less, for example.

  In the battery of the present invention, the electrode includes an electrode current collector that contacts the aqueous electrolyte. The electrode current collector is not particularly limited as long as it can exchange electrons with an active material (sulfur compound). For example, carbon blacks such as ketjen black and acetylene black, natural graphite such as flaky graphite, It may include graphite such as artificial graphite and expanded graphite, and conductive fibers such as carbon fiber and metal fiber. The electrode current collector may be a metal such as platinum, copper, silver, nickel, or aluminum, or may be an organic conductive material such as a polyphenylene derivative. Alternatively, a hole through which the aqueous electrolyte solution can permeate may be provided in the electrode current collector, and electrons may be exchanged between the electrode current collector and the aqueous electrolyte solution through this hole.

  In the battery of the present invention, when using an aqueous electrolyte solution in which a sulfur compound and a water-soluble compound are dissolved as a positive electrode, a material that is electrochemically stable in the potential range when the negative electrode active material used is charged and discharged is used. For example, a zinc metal plate may be used. At this time, the aqueous electrolyte solution of the negative electrode may be an aqueous solution according to the material of the negative electrode, and may include, for example, zinc ions. The negative electrode and the aqueous electrolyte solution for the negative electrode may be appropriately selected in consideration of battery performance.

  In the battery of the present invention, the separator is not particularly limited as long as it has a composition that can withstand the use conditions of the battery. For example, an ion conductive polymer film that can conduct ions or an ion conductive solid electrolyte film is used. Can do. Examples of the ion conductive polymer membrane include a perfluorocarbon material (tetrafluoroethylene-perfluorovinyl copolymer) composed of a hydrophobic tetrafluoroethylene skeleton composed of carbon-fluorine and a perfluoro side chain having a sulfonic acid group. ) And the like. Examples of the ion conductive solid electrolyte membrane include cation conductive glass (oxide glass).

  In the battery of the present invention, the liquid feeding unit may be a liquid feeding pump, for example. The aqueous electrolyte solution for the positive electrode and the negative electrode may be circulated in a predetermined amount using a liquid feed pump, and the predetermined flow rate can be appropriately set according to the battery scale. In addition, the liquid feeding unit may include a circulation path connected to the positive electrode chamber, the liquid feeding pump, and the electrolytic solution tank, and circulate the positive aqueous electrolyte solution. In addition, the liquid feeding unit may include a circulation path connected to the negative electrode chamber, the liquid feeding pump, and the electrolyte tank, and circulate the aqueous electrolyte solution of the negative electrode.

  FIG. 1 is an explanatory diagram showing an outline of the configuration of the redox flow battery 10. The redox flow battery 10 includes a case 12, a separator 18 that separates the inside of the case 12 into a positive electrode chamber 14 and a negative electrode chamber 16, a positive current collector 20 disposed in the positive electrode chamber 14, and a negative electrode chamber 16. The negative electrode current collector plate 22 was provided. In the redox flow battery 10, a positive electrode side circulation path 26 is provided between the positive electrode chamber 14 and a positive electrode aqueous electrolyte tank 24 that stores the positive electrode aqueous electrolyte, and a positive electrode side circulation pump is provided in the middle of the positive electrode side circulation path 26. 28 is attached. On the other hand, a negative electrode side circulation path 32 is provided between the negative electrode chamber 16 and the negative electrode aqueous electrolyte solution tank 30 for storing the negative electrode aqueous electrolyte solution, and a negative electrode side circulation pump 34 is attached in the middle of the negative electrode side circulation path 32. Yes. In this redox flow battery 10, a case where an aqueous electrolyte solution in which a sulfur compound and a water-soluble compound are dissolved is used as a positive electrode will be described as an example. The positive electrode aqueous electrolyte solution includes a sulfur compound as an active material, an aldehyde, A water-soluble compound which is at least one of ketones and amides is dissolved. The positive electrode-side circulation pump 28 circulates the positive electrode aqueous electrolyte and the negative electrode-side circulation pump 34 circulates the negative electrode aqueous electrolyte so that charging and discharging are performed. In addition, when combining with a more noble electrode such as using a bromine-based electrolyte, a redox flow battery having the same configuration in which the aqueous electrolyte of the present invention is used as a negative electrode electrolyte can be used.

  The battery of the present invention described in detail above includes an aqueous electrolyte solution in which a sulfur compound as an active material and a water-soluble compound that is at least one of aldehydes, ketones, and amides are dissolved. Efficiency can be further increased. The reason why such an effect is obtained is that, for example, there is some interaction such as forming a complex between a water-soluble compound having a carbonyl group in the molecule and a sulfur compound which is an active material present in the aqueous solution. It is assumed that the charge exchange on the electrode occurs easily, thereby suppressing the voltage drop during sulfur reduction and further improving the energy efficiency.

  It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be implemented in various modes as long as it belongs to the technical scope of the present invention.

  For example, in the above-described embodiment, the redox flow battery has been described. However, the present invention is not particularly limited thereto, and the electrolytic solution may not be circulated. Even in this case, since the aqueous electrolyte contains a sulfur compound that is an active material and a water-soluble compound, energy efficiency can be further improved.

  Below, the example which produced the redox flow battery of this invention concretely is demonstrated as an Example.

[Evaluation cell]
The redox flow cell shown in FIG. 1 was produced. The configuration of the cell will be described below. A zinc metal plate was used as the negative electrode, and a 0.5N sodium hydroxide aqueous solution in which zinc oxide was suspended and saturated was used as the aqueous electrolyte solution for the negative electrode. A carbon-impregnated carbon felt was used as the positive electrode current collector, and a 0.5N sodium hydroxide aqueous solution containing 10% by mass of sodium sulfide was used as the aqueous electrolyte solution of the positive electrode. The electrode was 2.5 cm square. A cation exchange membrane Nafion N324 (registered trademark) was used as a diaphragm separating the aqueous electrolyte solution of the positive electrode and the aqueous electrolyte solution of the negative electrode. Using the redox flow cell of FIG. 1, the positive and negative electrode electrolytes were respectively flowed at a rate of 5.5 ml / min using a roller pump, and the current was changed in the order of 50 mA, 20 mA, 10 mA, 5 mA, 2 mA, 1 mA, and 15 Charging for 30 minutes, discharging for 30 seconds and discharging for 15 minutes were repeated, and charging and discharging waveforms were measured. In FIG. 1, the aqueous electrolyte solution flows through the surface of the current collector. However, in this experiment, the aqueous electrolyte solution was circulated so that the aqueous electrolyte solution passed through the carbon felt. In addition, this time, in order to examine the effect of adding a water-soluble compound to the sulfide electrolyte, the negative electrode was evaluated using a zinc metal plate so that the potential was constant. However, other negative electrodes can be used as a counter electrode. Alternatively, an aqueous bromide solution or the like may be used as the positive electrode electrolyte, and an aqueous electrolyte solution in which sulfides and water-soluble compounds are dissolved may be used as the negative electrode electrolyte solution.

[Examples 1 to 4]
Dimethylformamide (DMF) was used as a water-soluble compound, and the aqueous electrolyte solution (10% by mass) of the positive electrode was adjusted so that the DMF concentrations were 15% by volume, 20% by volume, 35% by volume, and 50% by volume, respectively. A predetermined amount of DMF was added to and mixed with sodium sulfide / 0.5N aqueous sodium hydroxide solution). The redox flow cells using this positive electrode aqueous electrolyte were designated as Examples 1 to 4, respectively.

[Comparative Examples 1 and 2]
The cells obtained through the same steps as in Example 1 except that the concentration of DMF was 0% by volume and 10% by volume were used as Comparative Examples 1 and 2, respectively.

[Examples 5 to 7]
Acetone was used instead of dimethylformamide as an additive, and the aqueous electrolyte solution of the positive electrode (10% by mass sodium sulfide / 0.5N sodium hydroxide) was adjusted so that the concentrations were 10% by volume, 15% by volume, and 20% by volume, respectively. The cells obtained through the same steps as in Example 1 except that a predetermined amount of acetone was added to the aqueous solution) and mixed were designated as Examples 5 to 7, respectively.

[Examples 8 and 9]
Glucose is used as an additive in place of dimethylformamide, and glucose is added to the aqueous electrolyte solution (10% by mass sodium sulfide / 0.5N sodium hydroxide aqueous solution) of the positive electrode so that the concentration becomes 10% by mass and 20% by mass, respectively. A cell obtained through the same steps as in Example 1 except that a predetermined amount was mixed was designated as Examples 8 and 9, respectively.

[Comparative Example 3]
Acetone was used in place of dimethylformamide as an additive, and a predetermined amount of acetone was added to the positive electrode aqueous electrolyte solution (10 mass% sodium sulfide / 0.5N sodium hydroxide aqueous solution) and mixed so that the concentration became 5% by volume. A cell obtained through the same steps as in Example 1 was used as Comparative Example 3 except for the above.

[Comparative Examples 4 to 8]
Implemented except that 20% by volume of isopropyl alcohol (i-PrOH), dimethyl sulfoxide (DMSO), sulfolane (SUL) or 20% by mass of sodium formate (FOR) and sodium acetate (Ac) were added as water-soluble compounds. Cells obtained through the same steps as in Example 1 were designated as Comparative Examples 4 to 8, respectively.

(Measurement result)
Using the non-aqueous electrolytes of Examples 1 to 4 and Comparative Examples 1 and 2 described above, charge / discharge waveforms were measured under the above conditions. FIG. 2 shows the charge / discharge measurement results when the redox flow batteries of Examples 1 to 4 and Comparative Examples 1 and 2 were used and the current value was 1 mA. FIG. 3 is an explanatory diagram showing the relationship between the DMF concentration and the voltage difference between the charge voltage and the discharge voltage. As shown in FIG. 3, it was found that in Comparative Examples 1 and 2 (no DMF added and low concentration), polarization of 100 to 200 mV occurred even at a low current. Since the charging voltage at this time is around 0.7V, it was found that a loss of 15 to 30% was lost in terms of energy efficiency. On the other hand, when DMF is 15% by volume, more preferably 20% by volume or more, the polarization is drastically reduced to about 1/10 compared to the case of no addition, with only 20 mV at 1 mA. Therefore, it was found that the addition of DMF is effective in improving energy efficiency. In addition, when DMF was added to an aqueous solution containing sodium sulfide, the color of the solution changed, and some interaction occurred, such as forming a complex between the alkali metal sulfide present in the aqueous solution and DMF. Therefore, it is assumed that charge exchange on the electrode occurs easily. With respect to this DMF concentration, 50% by volume is effective for reducing the polarization of 1 mA, but according to the results of measurement omitted at 50 mA, an increase in charge voltage and a decrease in discharge voltage were observed. This was presumably because the conductivity of the electrolyte decreased with increasing DMF concentration. As for the density | concentration of DMF, it turned out that a lower density | concentration is more favorable about the use for which a big current is calculated | required. Therefore, it was found that the additive concentration of the water-soluble compound is more preferably 15% by volume or more and 50% by volume or less.

  FIG. 4 shows charge / discharge measurement results when the redox flow batteries of Examples 5 to 7 and Comparative Examples 1 and 3 were used and the current value was 1 mA. It was found that when acetone was used, a polarization reduction effect was exhibited at 10% by volume. However, on the high concentration side, acetone was uniformly dissolved at 20% by volume, but was not dissolved at 50% by volume and was separated into two layers. For this reason, when dissolving acetone in aqueous electrolyte solution, it turned out that it is more preferable to make 30 volume into the maximum, More preferably, it shall be 20 volume% or less.

  The results of evaluating the effect of adding various water-soluble compounds are shown in Table 1. Table 1 shows the charge / discharge voltage difference at a current value of 2 mA at 20% by volume or 20% by mass of each of the examples and comparative examples. As shown in Table 1, it was found that all the comparative examples except acetone, DMF, and glucose had a small polarization reduction effect. Note that “there is a polarization reduction effect” does not indicate that the polarization is zero, and the charge / discharge voltage difference at a low current (for example, 2 mA) when no water-soluble compound is added is “1”. In this case, it means that the value is smaller than this. For example, a state in which the value is suppressed to at least half (0.5 or less) is more preferable.

  In Example 8 in which 10% by mass of glucose was added as an additive, the charge / discharge voltage difference at a current of 2 mA was 133 mV, which was 0.36 V compared to 370 mV in Comparative Example 1 without addition. From this, it was found that the concentration of glucose showed a polarization reduction effect at 10% by mass or more. Moreover, when 20 mass% was added, as shown in Example 9, the polarization reduction effect was high, and the charge / discharge voltage difference was 0.60 mV. It was found that the glucose concentration was more preferably 15% by mass or more.

  From the above experimental results, the water-soluble compounds to be added are organic substances having a carbonyl group, specifically, ketones such as acetone, amides such as dimethylformamide, aldehydes such as glucose, and supporting salts. It was found that it is preferable to dissolve at least 10% by volume in an aqueous solution in which the sulfide active material is dissolved. In consideration of solubility in water, it was presumed that a compound having a short carbon chain (for example, having 6 or less carbon atoms) was preferable. Alcohols such as isopropyl alcohol which is a reduced form of acetone have no effect, and oxidants such as sodium acetate and sodium formate have no effect. Further, dimethyl sulfoxide and sulfolane having an oxygen double bond were not effective, and were considered to be specific effects for carbonyl structures such as ketones. The concentration is preferably 10% by volume or more, and the upper limit is preferably a range in which the water-soluble compound and water are uniformly mixed. At a high concentration, the resistance of the electrolytic solution itself increases, and voltage loss due to the resistance occurs, so 50% by volume was considered the upper limit.

  The present invention is applicable to the battery industry.

10 redox flow battery, 12 case, 14 positive electrode chamber, 16 negative electrode chamber, 18 separator, 20 positive electrode current collector plate, 22 negative electrode current collector plate, 24 positive electrode aqueous electrolyte tank, 26 positive electrode side circulation path, 28 positive electrode side circulation pump, 30 negative electrode aqueous electrolyte tank, 32 negative electrode side circulation path, 34 negative electrode side circulation pump.

Claims (5)

A positive electrode;
A negative electrode,
A separator that separates into a positive electrode chamber and a negative electrode chamber;
An aqueous system in which a sulfur compound which is one or more of alkali metal sulfides and alkali metal polysulfides and which is an active material and a water-soluble compound which is at least one of aldehydes, ketones and amides are dissolved An electrolyte solution,
When the water-soluble compound is an amide, the content of the amide in the aqueous electrolyte is 15% by volume or more,
When the water-soluble compound is an aldehyde, the content of the aldehyde in the aqueous electrolyte is 10% by mass or more,
Wherein when the water-soluble compound is a ketone state, and are the content of the ketones of the water-based electrolytic solution is more than 10% by volume,
A liquid feeding part connected to the positive electrode chamber, wherein the aqueous electrolyte solution is accommodated in the positive electrode chamber in contact with the positive electrode and circulated by the liquid feeding part, or connected to the negative electrode chamber; The battery is provided with a liquid feeding section, and the aqueous electrolyte is contained in the negative electrode chamber in contact with the negative electrode and is distributed by the liquid feeding section . When the water-soluble compound is an amide, the content of the amide in the aqueous electrolyte is 50% by volume or less,
When the water-soluble compound is an aldehyde, the content of the aldehyde in the aqueous electrolyte is 50% by mass or less,
2. The battery according to claim 1, wherein when the water-soluble compound is a ketone, the content of the ketone in the aqueous electrolyte is 30% by volume or less. The water-based electrolyte includes R ¹ —C (═O) —R ² (wherein R ¹ and R ² may be the same as or different from each other, hydrogen, hydrocarbon group and — Any one of NR ³ R ⁴ (provided that R ³ and R ⁴ may be the same or different, and each may be the same or different from either R ¹ or R ² , The battery according to claim 1 or 2, wherein any one of hydrogen and hydrocarbon groups)) is dissolved. The aldehydes include one or more sugars including formaldehyde, acetaldehyde and glucose,
The amides include one or more of dimethylformamide and diethylformamide,
The battery according to claim 1, wherein the ketones include one or more of acetone and diethyl ketone. The battery is a zinc-sodium sulfide battery, and the aqueous electrolyte is present in the positive electrode,
The battery according to any one of claims 1 to 4, wherein the battery is a sodium sulfide-bromine battery, and the aqueous electrolyte solution is present in a negative electrode.

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