An organic active substance and a preparation method and negative electrode electrolyte based thereon

Abstract

The present application relates to the technical field of aqueous organic liquid flow battery electrolytes, and discloses an organic active substance and a preparation method and negative electrode electrolyte based thereon, wherein the preparation method of the organic active substance comprises: dispersing substance A, substance B and Pd catalyst in an organic solvent, stirring the reaction to obtain a mixed liquid, solid-liquid separation, drying, dispersing the obtained precipitate in concentrated sulfuric acid, reflux reaction, lowering the temperature after the reaction, centrifuging, collecting the solid precipitate, and obtaining the organic active substance. The active organic matter prepared by this method can transfer 4 electrons per molecule during the battery reaction process, which can effectively improve the energy density of the electrolyte. In addition, sulfonation can also effectively increase the solubility of the active organic matter in aqueous solvents, further improving the energy density of the electrolyte.

Description

Technical Field

[0001] The present application relates to the technical field of aqueous organic liquid flow battery electrolytes, and in particular to an organic active substance and a preparation method and a negative electrode electrolyte based thereon. Background Art

[0002] Liquid flow batteries are a type of energy storage system with high cycle efficiency and controllable properties, which holds great promise. Organic liquid flow batteries use a water-based electrolyte, eliminating the risk of fire or explosion. Compared to common all-vanadium liquid flow batteries, organic active substances can be mass-produced through simple chemical synthesis without relying on rare metals. The electrolyte is based on elements such as carbon, hydrogen, oxygen, and nitrogen, and the synthesis process is environmentally friendly and recyclable. They offer excellent properties such as low cost, diverse types, and strong controllability. However, the active substances in organic liquid flow batteries have poor solubility and low energy efficiency in aqueous solvents, which directly affects the efficiency and capacity of aqueous organic liquid flow batteries, leading to increased construction and operating costs. Summary of the Invention

[0003] The purpose of this application is to provide an organic active substance and a preparation method and negative electrode electrolyte based thereon, by adjusting the structure of the organic active substance, increasing the number of electrons in the redox transfer of a single molecule of the active substance; by modifying the functional groups of the organic active substance, improving the solubility, and thus solving the problems of poor solubility and low energy efficiency of the organic active substance in aqueous solvents.

[0004] To achieve the above objectives, this application provides the following technical solutions:

[0005] In a first aspect, an embodiment of the present application provides an organic active substance, wherein the structure of the organic active substance is:

[0006] .

[0007] In a second aspect, embodiments of the present application provide a method for preparing the aforementioned organic active material, comprising: dispersing substance A, substance B, and a Pd catalyst in an organic solvent, stirring the mixture to obtain a mixed solution, separating the solid and liquid, drying the mixture, dispersing the resulting precipitate in concentrated sulfuric acid, refluxing the mixture, and, after completion of the reaction, lowering the temperature, centrifuging the mixture, and collecting the solid precipitate to obtain an organic active material (DPZ). The substance generated by the reaction of substance A and substance B contains four phenazine nitrogen atoms. During the redox reaction during battery charge and discharge, a single molecule can provide four electron transfers. The reaction process is as follows:

[0008]

[0009] Under conditions of constant electrolyte concentration, this can effectively increase the energy density of the electrolyte. Alternatively, under conditions of constant energy density, the electrolyte concentration can be maintained at a low level, promoting the mass transfer rate during the battery's redox reaction, reducing concentration polarization, and improving battery efficiency. The introduction of sulfonic acid groups is an electrophilic substitution reaction. The benzene ring of phenazine, especially the carbon atom at the para position, is less susceptible to the electron-withdrawing effect of the nitrogen atom, making it more conducive to the growth of sulfonic acid groups. Through the action of concentrated sulfuric acid, sulfonic acid groups can be grown on organic molecules. Sulfonic acid groups contain three highly polar oxygen atoms (two double-bonded oxygen atoms and one single-bonded oxygen). These oxygen atoms can form multiple hydrogen bonds with water molecules, effectively increasing the solubility of active organic compounds in aqueous solvents.

[0010] Preferably, the basic structure of the molecular formula of substance A contains a benzene ring, a nitro group, and other substituents, the nitro group and other substituents are in the ortho position and directly connected to the benzene ring, and is selected from one of 2-bromonitrobenzene, 2-nitrobenzonitrile, o-nitrophenol, 1-fluoro-2-nitrobenzene, 1-iodo-2-nitrobenzene, and 2-nitrophenylacetic acid; the substance B is a benzidine substance selected from 3,3'-diaminobenzidine, 3,3'-dihydroxybenzidine, and 3,3'-methoxybenzidine; and the organic solvent is one of acetone, benzene, and N,N-dimethylformamide.

[0011] Preferably, the mass ratio of substance A, substance B, Pd catalyst and organic solvent is 1: (0.5-1): (0.01-0.03): (10-50).

[0012] Preferably, the mass ratio of the precipitate to concentrated sulfuric acid is 1:(20-100); the temperature of the reflux reaction is 70-100° C., and the time is 12-24 hours.

[0013] In a third aspect, an embodiment of the present application provides a negative electrode electrolyte, wherein the negative electrode electrolyte is made from the organic active substance described above or the organic active substance prepared by the preparation method described above.

[0014] Preferably, the negative electrode electrolyte further includes an alkaline solution and a composite additive.

[0015] Preferably, the concentration of the organic active substance in the negative electrode electrolyte is 0.1-1 mol / L.

[0016] Preferably, the alkaline solution is one of potassium hydroxide solution and sodium hydroxide solution, and the concentration of the alkaline solution in the negative electrode electrolyte is 0.5-3 mol / L.

[0017] Preferably, the composite additive comprises an inorganic additive and an organic additive in a mass ratio of 1:(0.05-0.5), wherein the inorganic additive is sodium sulfite or potassium sulfite, and the organic additive is polyvinylpyrrolidone (PVP) with a K value of less than 60. The content of the composite additive in the negative electrolyte is 1-10 g / L. Under strong alkaline conditions, sodium sulfite or potassium sulfite releases reducing sulfur dioxide gas, which effectively prevents oxidation of the negative electrolyte and improves the battery's energy efficiency and capacity retention. Polyvinylpyrrolidone, a water-soluble polymer, exhibits film-forming, adhesive, hygroscopic, and solubilizing properties, enhancing material transport and dispersion in the electrolyte, thereby improving battery efficiency. However, it is worth noting that higher molecular weight and concentration of PVP can increase electrolyte viscosity, adversely affecting battery performance, necessitating controlled molecular weight and concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of a method for preparing a negative electrode electrolyte in the present application. DETAILED DESCRIPTION

[0019] To make the objectives, technical solutions, and advantages of this application more clearly understood, this application is further described in detail below with reference to the accompanying drawings and examples. However, it should be understood that the specific embodiments described herein are merely intended to illustrate this application and are not intended to limit the scope of this application. In addition, descriptions of well-known structures and technologies are omitted in the following description to avoid unnecessary confusion regarding the concepts of this application.

[0020] like Figure 1As shown, a negative electrode electrolyte is composed of an organic active substance with a concentration of 0.1~1 mol / L, an alkaline solution with a concentration of 0.5~3 mol / L, and a composite additive with a concentration of 1~10 g / L. The preparation method of the organic active substance comprises: dispersing substance A, substance B, a Pd catalyst (the Pd catalyst and 1,1'-binaphthyl-2,2'-bisdiphenylphosphine may also be present) and an organic solvent in an organic solvent at a mass ratio of 1:(0.5-1):(0.01-0.03):(10-50), stirring to react to obtain a mixed solution, separating the solid and the liquid, and drying; dispersing the obtained precipitate with concentrated sulfuric acid at a mass ratio of 1:(20-100), and reflux reaction at 70-100°C for 12-24 hours. After the reaction is completed, the temperature is lowered, centrifugation is performed, and the solid precipitate is collected to obtain the organic active substance. The basic molecular structure of substance A contains a benzene ring, a nitro group, and other substituents, wherein the nitro group and other substituents are located in the ortho position and directly connected to the benzene ring; substance B is a benzidine-type substance. The alkaline solution is one of potassium hydroxide solution and sodium hydroxide solution. The composite additive consists of an inorganic additive and an organic additive in a mass ratio of 1:(0.05-0.5). The inorganic additive is either sodium sulfite or potassium sulfite, and the organic additive is polyvinylpyrrolidone with a K value less than 60. Substance A is either 2-bromonitrobenzene, 2-nitrobenzonitrile, o-nitrophenol, 1-fluoro-2-nitrobenzene, 1-iodo-2-nitrobenzene, or 2-nitrophenylacetic acid. Substance B is either 3,3'-diaminobenzidine, 3,3'-dihydroxybenzidine, or 3,3'-methoxybenzidine. The organic solvent is either acetone, benzene, or N,N-dimethylformamide.

[0021] Example 1: The negative electrolyte of this embodiment is prepared by the following scheme

[0022] A negative electrode electrolyte is composed of an organic active substance with a concentration of 0.1 mol / L, a potassium hydroxide solution with a concentration of 0.5 mol / L, and a composite additive composed of sodium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.05 with a concentration of 1 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0023] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: 2-bromonitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and acetone are dispersed in an organic solvent in a mass ratio of 1:0.5:0.01:10, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying. The obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:20, and the temperature is refluxed at 100°C for 12 hours. After the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0024] Example 2: The negative electrolyte of this embodiment is prepared using the following scheme

[0025] A negative electrode electrolyte is composed of an organic active substance with a concentration of 1 mol / L, a sodium hydroxide solution with a concentration of 3 mol / L, and a composite additive composed of potassium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.5 at a concentration of 10 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0026] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: 2-nitrobenzonitrile, 3,3'-dihydroxybenzidine, Pd catalyst and benzene are dispersed in an organic solvent in a mass ratio of 1:1:0.03:50, stirred for reaction to obtain a mixed solution, solid-liquid separation, and drying. The obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:100, and refluxed at 70°C for 24 hours. After the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0027] Example 3: The negative electrolyte of this embodiment is prepared using the following scheme

[0028] A negative electrode electrolyte is composed of an organic active substance with a concentration of 0.3 mol / L, a potassium hydroxide solution with a concentration of 1 mol / L, and a composite additive composed of sodium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.1 at a concentration of 50 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0029] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: o-nitrophenol, 3,3'-methoxybenzidine, Pd catalyst and N,N-dimethylformamide are dispersed in an organic solvent in a mass ratio of 1:0.7:0.02:20, stirred for reaction to obtain a mixed solution, solid-liquid separation, and drying. The obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:60, and the reaction is refluxed at 80°C for 15 hours. After the reaction is completed, the temperature is lowered, centrifugation is performed, and the solid precipitate is collected to obtain the organic active material.

[0030] Example 4: The negative electrode electrolyte of this embodiment is prepared using the following scheme

[0031] A negative electrode electrolyte is composed of an organic active substance with a concentration of 0.5 mol / L, a potassium hydroxide solution with a concentration of 2 mol / L, and a composite additive composed of sodium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.3 at a concentration of 8 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0032] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: 1-fluoro-2-nitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and N,N-dimethylformamide are dispersed in an organic solvent in a mass ratio of 1:0.8:0.03:40, stirred for reaction to obtain a mixed solution, solid-liquid separation, and drying. The obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:70, and the reaction is refluxed at 80°C for 20 hours. After the reaction is completed, the temperature is lowered, centrifugation is performed, and the solid precipitate is collected to obtain the organic active material.

[0033] Example 5: The negative electrode electrolyte of this embodiment is prepared using the following scheme

[0034] A negative electrode electrolyte is composed of an organic active substance with a concentration of 0.8 mol / L, a potassium hydroxide solution with a concentration of 2 mol / L, and a composite additive composed of potassium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.4 at a concentration of 7 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0035] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: 1-iodo-2-nitrobenzene, 3,3'-dihydroxybenzidine, Pd catalyst and benzene are dispersed in an organic solvent in a mass ratio of 1:0.7:0.03:35, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying. The obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:40, and the reaction is refluxed at 80°C for 22 hours. After the reaction is completed, the temperature is lowered, centrifugation is performed, and the solid precipitate is collected to obtain the organic active material.

[0036] Example 6: The negative electrolyte of this embodiment is prepared using the following scheme

[0037] A negative electrode electrolyte is composed of an organic active substance with a concentration of 1 mol / L, a potassium hydroxide solution with a concentration of 2 mol / L, and a composite additive composed of sodium sulfite and polyvinyl pyrrolidone with a mass ratio of 1:0.5 with a concentration of 4 g / L. The solution formed by the three is the negative electrode electrolyte of this embodiment.

[0038] The preparation method of the organic active material used in the negative electrode electrolyte of this embodiment is as follows: 2-nitrophenylacetic acid, 3,3'-diaminobenzidine, Pd catalyst, 1,1'-binaphthyl-2,2'-bisdiphenylphosphine and N,N-dimethylformamide are dispersed in an organic solvent in a mass ratio of 1:0.5:0.02:0.02:30, stirred for reaction to obtain a mixed solution, solid-liquid separation, and drying. The obtained precipitate is dispersed with concentrated sulfuric acid in a mass ratio of 1:80, refluxed at 90°C for 24 hours, and the reaction is completed. After the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0039] Comparative Example 1: The preparation process of the negative electrode electrolyte in this comparative example differs from that in Example 1 in that phenazine is used as the organic active material. A negative electrode electrolyte solution comprising 0.1 mol / L phenazine, 0.5 mol / L potassium hydroxide solution, and a 1 g / L composite additive consisting of sodium sulfite and polyvinyl pyrrolidone in a mass ratio of 1:0.05 is prepared. The resulting solution is the negative electrode electrolyte in this comparative example.

[0040] Comparative Example 2: The preparation process of the negative electrode electrolyte in this comparative example differs from that in Example 1 in that no composite additive is added. A negative electrode electrolyte is prepared by combining a 0.1 mol / L organic active substance and a 0.5 mol / L potassium hydroxide solution. The solution formed by the three is the negative electrode electrolyte in this comparative example.

[0041] The preparation method of the organic active material used in the negative electrode electrolyte of this comparative example is as follows: 2-bromonitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and acetone are dispersed in an organic solvent in a mass ratio of 1:0.5:0.01:10, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying; the obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:20, refluxed at 100°C for 12 hours, and after the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0042] Comparative Example 3: The preparation process of the negative electrode electrolyte in this comparative example differs from that in Example 1 in that the composite additive does not include an organic additive. A negative electrode electrolyte solution comprising 0.1 mol / L organic active material, 0.5 mol / L potassium hydroxide solution, and 1 g / L sodium sulfite is used as the negative electrode electrolyte in this comparative example.

[0043] The preparation method of the organic active material used in the negative electrode electrolyte of this comparative example is as follows: 2-bromonitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and acetone are dispersed in an organic solvent in a mass ratio of 1:0.5:0.01:10, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying; the obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:20, refluxed at 100°C for 12 hours, and after the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0044] Comparative Example 4: The preparation process of the negative electrode electrolyte in this comparative example differs from that in Example 1 in that the composite additive does not include an inorganic additive. A negative electrode electrolyte solution comprising 0.1 mol / L organic active material, 0.5 mol / L potassium hydroxide solution, and 0.05 g / L polyvinyl pyrrolidone is used as the negative electrode electrolyte in this comparative example.

[0045] The preparation method of the organic active material used in the negative electrode electrolyte of this comparative example is as follows: 2-bromonitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and acetone are dispersed in an organic solvent in a mass ratio of 1:0.5:0.01:10, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying; the obtained precipitate and concentrated sulfuric acid are dispersed in a mass ratio of 1:20, refluxed at 100°C for 12 hours, and after the reaction is completed, the temperature is lowered, centrifuged, and the solid precipitate is collected to obtain the organic active material.

[0046] Comparative Example 5: The preparation process of the organic active material used in the negative electrode electrolyte of this comparative example differs from that of Example 1 in that concentrated sulfuric acid treatment is not used for precipitation. A negative electrode electrolyte comprising 0.1 mol / L organic active material, 0.5 mol / L potassium hydroxide solution, and a 1 g / L composite additive consisting of sodium sulfite and polyvinyl pyrrolidone in a mass ratio of 1:0.05 is used as the negative electrode electrolyte of this comparative example.

[0047] The preparation method of the organic active substance in the negative electrode electrolyte of this comparative example is as follows: 2-bromonitrobenzene, 3,3'-diaminobenzidine, Pd catalyst and acetone are dispersed in an organic solvent in a mass ratio of 1:0.5:0.01:10, stirred for reaction to obtain a mixed liquid, solid-liquid separation, and drying. The obtained precipitate is the organic active substance of this comparative example.

[0048] Comparative Example 6: All-vanadium redox flow battery was used as a control.

[0049] Saturation concentration test: The organic active substances prepared in Examples 1 to 6 and Comparative Examples 1 to 6 were added at a constant temperature of 25°C at a rate of 0.01 mol (the corresponding molar amount was calculated based on the weight of the precipitate not treated with concentrated sulfuric acid) into 100 mL of 1 mol / L sodium hydroxide solution. The mixture was stirred and dissolved until saturated. The saturation concentration of the organic active substance was tested.

[0050] Battery efficiency test: Using the negative electrode electrolyte prepared in Examples 1 to 6 and Comparative Examples 1 to 6 as the negative electrode and controlling the theoretical capacity of the active material to be consistent, and using 0.3 mol / L potassium ferrocyanide as the positive electrode, charge and discharge were carried out under the same operating conditions to test the coulombic efficiency, energy efficiency, voltage efficiency, maximum discharge capacity and capacity retention rate of the battery.

[0051] The test results are shown in Table 1:

[0052] Table 1 Summary of test results

[0053] Test indicators Saturation concentration (mol / L) Coulombic efficiency (%) Energy efficiency (%) Voltage efficiency (%) Capacity retention after 500 cycles (%) Example 1 1.57 99.97 82.32 82.34 98% Example 2 1.53 99.99 81.24 81.24 96% Example 3 1.41 99.98 82.11 82.12 99% Example 4 1.48 99.96 82.20 82.23 99% Example 5 1.55 99.99 81.74 81.75 98% Example 6 1.62 99.98 81.42 81.44 96% Comparative Example 1 0.02 - - - - Comparative Example 2 1.56 98.66 79.31 80.39 83% Comparative Example 3 1.52 98.92 80.74 81.62 92% Comparative Example 4 1.58 99.08 80.85 81.60 88% Comparative Example 5 0.03 - - - - Comparative Example 6 - 96.85 83.72 86.49 68%

[0054] Note: (1) Comparative Examples 1 and 5 were not able to charge and discharge normally because of low concentrations, and no battery data was collected;

[0055] (2) In Comparative Example 6, the all-vanadium liquid flow battery is an acidic aqueous solution, and the conditions cannot be kept consistent, so the solubility test was not performed.

[0056] It can be seen from the saturation concentration test results in Table 1 that the solubility of the active organic matter prepared by the method of the present application is significantly better than that of the same type of pyrazine, mainly because the water solubility of the active organic matter is improved by growing sulfonic acid groups on the molecular structure. In addition, it can be seen from Comparative Examples 2 to Comparative Examples 4 that as the degree of sulfonation increases, the solubility of the active organic matter also gradually increases. It can be seen from the efficiency results in Table 1 that as the concentration of the negative electrode electrolyte increases, the energy efficiency and voltage efficiency decrease. Therefore, under conditions of equal energy density, if the negative electrode electrolyte can be maintained at a low concentration, the material transfer rate during the battery redox reaction can be effectively promoted, the concentration polarization can be reduced, and the efficiency of the battery can be improved. At the same time, polyvinyl pyrrolidone, as a water-soluble polymer compound, has film-forming properties, adhesion, hygroscopicity and solubilization, which can improve the material transfer and dispersibility of the negative electrode electrolyte, thereby improving the efficiency of the battery. In addition, it can be seen from the capacity retention results in Table 1 that the addition of composite additives can effectively improve the capacity retention of the battery. This is mainly because sodium sulfite or potassium sulfite can release reducing sulfur dioxide gas under strong alkaline conditions. These gases can effectively prevent the negative electrode electrolyte from being oxidized, thereby improving the energy efficiency and capacity retention of the battery.

[0057] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements or improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A negative electrode electrolyte, characterized in that The negative electrode electrolyte includes an organic active substance, an alkaline solution, and a composite additive. The preparation method of the organic active substance includes: dispersing substance A, substance B, and a Pd catalyst in an organic solvent, stirring to react, obtaining a mixed solution, separating the solid and the liquid, drying, dispersing the obtained precipitate in concentrated sulfuric acid, refluxing the mixture, lowering the temperature after the reaction, centrifuging, and collecting the solid precipitate to obtain the organic active substance. The substance A is one of 2-bromonitrobenzene, 1-fluoro-2-nitrobenzene, and 1-iodo-2-nitrobenzene; the substance B is 3,3'-diaminobenzidine; and the organic solvent is one of acetone, benzene, and N,N-dimethylformamide. Wherein, the structure of the organic active substance is: ； The sulfonic acid group in the organic active material is directly connected to the para position of the phenazine ring through a C-S bond, and the organic active material provides four electron transfer in a single molecule within the pH range of 7-14; The composite additive is composed of an inorganic additive and an organic additive in a mass ratio of 1:(0.05-0.5); the inorganic additive is one of sodium sulfite and potassium sulfite; the organic additive is polyvinyl pyrrolidone; the content of the composite additive in the negative electrode electrolyte is 1-10 g / L.

2. The negative electrode electrolyte according to claim 1, wherein The mass ratio of the substance A, substance B, Pd catalyst and organic solvent is 1: (0.5-1): (0.01-0.03): (10-50).

3. The negative electrode electrolyte according to claim 1, wherein The mass ratio of the precipitate to concentrated sulfuric acid is 1:(20-100); the temperature of the reflux reaction is 70-100° C., and the time is 12-24 hours.

4. The negative electrode electrolyte according to claim 1, wherein The concentration of the organic active substance in the negative electrode electrolyte is 0.1-1 mol / L.

5. The negative electrode electrolyte according to claim 1, wherein The alkaline solution is one of potassium hydroxide solution and sodium hydroxide solution, and the concentration of the alkaline solution in the negative electrode electrolyte is 0.5-3 mol / L.

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