Zinc-bromine energy storage battery based on four-electron conversion reaction

Abstract

The invention belongs to the technical field of batteries, and particularly discloses a zinc-bromine energy storage battery based on a four-electron conversion reaction, which comprises a battery cell formed by mutually compounding a positive electrode, a diaphragm and a negative electrode, and an electrolyte for soaking the battery cell, the positive electrode comprises a current collector and a positive electrode material compounded on the surface of the current collector, and the diaphragm comprises a positive electrode material compounded on the surface of the current collector; the positive electrode material contains an additive A # imgabs0 #; the electrolyte at least contains zinc sulfate; the positive electrode material and / or the electrolyte also contains an additive C; the additive C is an electrolyte; anions of the additive A and the additive C at least comprise Br <-> and anions a capable of forming interbromides. The battery provided by the invention can obtain excellent electrochemical properties such as capacity, rate and the like based on a brand new four-electron mechanism.

Description

Technical Field

[0001] The present invention relates to a zinc-bromine battery in chemical energy storage technology, and in particular to the technical field of zinc-bromine batteries. Background Art

[0002] By storing and releasing energy into the grid through energy storage systems, intermittent renewable electricity can be transformed into a stable, safe, and efficient clean energy source, becoming a key technology for transforming my country's energy structure and ensuring energy supply security. In this context, the development of green and environmentally friendly, high-density energy storage batteries is particularly important. Halogen-based aqueous batteries offer inherently high safety, and the abundance of halogens, coupled with the fact that their production process does not require anhydrous conditions, further ensures their low cost. Aqueous electrolytes offer higher ionic conductivity than organic systems, resulting in higher power density and greater competitiveness in the field of large-scale energy storage. Zinc-iodine batteries are a classic type of halogen-based aqueous battery, attracting significant attention for their high safety, long life, and low cost. In recent years, a type of zinc-iodine battery that utilizes the four-electron conversion reaction of iodine molecules has been proposed, significantly improving the battery's energy and power density. Although bromine also has multiple valence states, allowing for the construction of electrodes with multi-electron conversion reactions to achieve higher energy density, existing zinc-bromine battery technology is still based on single-electron conversion of bromine, primarily due to the stability and solubility issues of the high-valence bromine active species. Summary of the Invention

[0003] In response to the problems existing in the prior art, the present invention provides a zinc-bromine energy storage battery based on a four-electron conversion reaction, aiming to obtain a zinc-bromine energy storage battery with excellent capacity and coulombic efficiency based on the four-electron conversion mechanism based on the adaptive synergy of the positive electrode and the electrolyte.

[0004] A zinc-bromine energy storage battery based on a four-electron conversion reaction, comprising a battery cell composed of a positive electrode, a separator, and a negative electrode, and an electrolyte for soaking the battery cell. The positive electrode comprises a current collector and a positive electrode material composited on its surface, wherein the positive electrode material comprises at least one additive A selected from Formulas 1 to 7.

[0005]

[0006]

[0007] In Formulas 1 to 7, R1 is a C1-C8 alkyl group, R2-R4 are independently H or a C1-C8 alkyl group; n is 1 to 8; and y is 20-1,000,000.

[0008] The electrolyte is an aqueous solution containing an electrolyte salt B (also referred to as additive B), wherein the cations in the electrolyte salt B include at least zinc ions; the cations may also include one or more of sodium, lithium, potassium, magnesium, hydrogen, and guanidine ions; and the anions include sulfate.

[0009] The positive electrode material and / or electrolyte may further contain an additive C; the additive C is an electrolyte;

[0010] The anions of the additives A and C contain at least Br - and anions a capable of forming brominated intermetallic compounds.

[0011] The present invention aims to provide a 2Br - / Br2 0 / 2Br + Zinc-bromine batteries with a four-electron reaction mechanism, however, earlier studies have found that in order to achieve this four-electron reaction mechanism, it is necessary to face implementation difficulties such as four-electron reaction induction, stability of high-valent Br, and dissolution of active substances. In response to this problem, the present invention innovatively combines a positive electrode containing additive A with an electrolyte containing electrolyte salt B, and further cooperates with the combined control of additive C and components, so that a four-electron reaction mechanism can be induced and a bromide intermetallic compound can be formed, thereby improving the stability of the high-valent bromine active substance. In addition, its dissolution can be suppressed, so that it is effectively confined to the positive electrode. In the present invention, through the combination of the additives A to C components and the addition method, an adaptive synergistic effect can be achieved, and the electrochemical capacity, voltage and coulombic efficiency of the battery can be significantly improved based on the new electrochemical mechanism.

[0012] In the present invention, the combination of the additive A having the structure described above in the positive electrode material and the electrolyte containing the electrolyte salt B, and the further combined control of the additive C dispersed in the positive electrode material and / or the electrolyte are the key to synergistically inducing the new four-electron reaction mechanism, improving the stability of its high-valent bromine, and reducing its dissolution.

[0013] In the additive A, R1 to R4 may be methyl, ethyl, propyl, butyl, pentyl, or hexyl. n may be an integer from 1 to 3. y may be 20,000 to 50,000.

[0014] As a preference, in the additive A, the X can be F - 、Cl - Br - , I - 、SCN - 、OTf - TFSI - At least one of, preferably Br - .

[0015] In the present invention, the additive C contains an electrolyte containing at least one cation selected from zinc, sodium, lithium, potassium, magnesium, calcium, aluminum, hydrogen, guanidine ion, and ammonium ion; wherein the anion is preferably F - 、Cl - Br - , I - 、SCN - 、OTf - TFSI - At least one of .

[0016] In the present invention, the additive A and the additive C contain at least Br and an anion (anion a) capable of forming a bromide intermetallic compound, wherein the anion a is, for example, F - 、Cl - , I - 、SCN - 、OTf - TFSI - The brominated compound formed can be, for example, at least one of BrI, BrCl, BrI, BrSCN, and BrOTf. In addition, it should be noted that the additives A and C provide Br - In addition to anion a, other anions are also allowed to be provided.

[0017] For example, in an embodiment of the present invention, the additive A provides at least Br - , the additive C at least provides anion a; or the additive C at least provides Br - , the additive A at least provides anion a. Alternatively, the additive A or additive C simultaneously provides Br - and anion a.

[0018] In the present invention, by further jointly controlling the composition and addition method of the additives A, electrolyte salt B and additive C in combination, the synergy can be unexpectedly improved, and the performance of the battery with the new reaction mechanism can be further improved to a certain extent.

[0019] Preferably, the additive A comprises at least an additive of formula 1. Research in the present invention shows that the preferred additive a, when added to the positive electrode material, unexpectedly exhibits better compatibility and synergy with the additive C and the electrolyte salt B contained in the electrolyte, unexpectedly further improving the efficiency and stability of the new four-electron reaction and reducing its dissolution, thereby further improving the electrochemical performance of the battery with the new reaction mechanism.

[0020] In the present invention, in the positive electrode material, the content of the additive A is above 20 wt.%, preferably 30 to 70 wt.%, and more preferably 35 to 60 wt.%.

[0021] In the present invention, the positive electrode material may further contain an additive C;

[0022] Preferably, in the positive electrode material, the weight ratio of the additive C to the additive A is 0.5 to 4:1, more preferably 0.5 to 1.5:1.

[0023] In the present invention, the positive electrode material further comprises a conductive agent and a binder;

[0024] In the present invention, the binder is a water-soluble polymer, a natural polymer or a mixture thereof, more preferably at least one of polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose and sodium carboxymethyl cellulose;

[0025] In the present invention, the amount of the binder can be adjusted according to conventional principles. For example, the amount of the binder used in the positive electrode material is less than or equal to 15 wt.%, and can further be 1 to 10 wt.%.

[0026] In the present invention, the conductive agent is at least one of carbon powder and carbon fiber; the carbon powder is at least one of Super P, acetylene black, carbon nanotubes, graphite, activated carbon, and Ketjen black; the carbon fiber is carbon fiber chopped strands with a length of 0.5 to 12 mm and a diameter of 5 to 10 μm. Preferably, the carbon fiber chopped strands are 1 to 3 mm and 7 μm in diameter.

[0027] In the present invention, the content of the conductive agent in the positive electrode material is less than or equal to 20 wt.%, and can further be 5 to 15 wt.%.

[0028] In the present invention, in the electrolyte, the cations in the electrolyte salt B contain at least zinc ions; the cations may also contain one or more of sodium, lithium, potassium, magnesium, hydrogen, and guanidine ions; the anions are sulfate, and F is also allowed to exist. - 、Cl - Br - , I - 、SCN - 、OTf - TFSI -At least one of the following; research in the present invention demonstrates that the addition of this preferred electrolyte salt B to the electrolyte unexpectedly further synergistically facilitates the localized storage of bromide and fluoride in the positive electrode, inhibiting their dissolution loss. This unexpectedly further improves the performance of the zinc-bromine battery based on the novel four-electron mechanism. Further preferably, the electrolyte salt B comprises at least zinc sulfate and optionally at least one of sodium chloride and sodium sulfate.

[0029] Preferably, the concentration of the electrolyte salt B in the electrolyte is greater than or equal to 1M until saturation. Considering the processing cost, it can be further 1 to 15M, more preferably 1 to 5M, and even more preferably 2.5 to 5M. Studies have shown that under the optimal ratio, Br + By stabilizing the electrons and confining them to the cathode, the performance can be further improved based on the four-electron mechanism.

[0030] In a preferred embodiment of the present invention, the electrolyte may further contain the additive C.

[0031] Preferably, the concentration of the additive C in the electrolyte is above 0.1M, and can further be 0.1-2M.

[0032] In the present invention, the zinc-bromine battery, except for the positive electrode containing additive A, the electrolyte containing additive C, and the additive C dispersed in the positive electrode and the electrolyte, other components, materials and battery structure can be conventional.

[0033] For example, in the present invention, the separator is one of a glass fiber membrane, a cellulose membrane, a polytetrafluoroethylene porous membrane, a polypropylene porous membrane, and a polyvinylidene fluoride porous membrane.

[0034] In the present invention, the negative electrode is zinc metal, zinc powder or a carbon material current collector that does not contain metallic zinc.

[0035] In the present invention, the zinc-bromine energy storage battery based on the four-electron conversion reaction refers to the 2Br - -Br2 0 -2Br + A zinc-bromine static battery with a four-electron conversion reaction;

[0036] In the present invention, the zinc-bromine energy storage battery is a zinc-bromine static battery.

[0037] During charging, the zinc-bromine battery of the present invention first oxidizes bromide ions to zero-valent bromine. With the help of nucleophilic anions, the zero-valent bromine is further oxidized to a halogen compound with a higher valent bromine. During this process, the active bromine species interact with the additive A in the positive electrode, while the cations of the inorganic salt migrate into the electrolyte, depositing zinc ions on the negative electrode surface. The reverse occurs during discharge. Because the higher valent bromine element is stored in the positive electrode material as an halogen compound, the decomposition and dissolution of the higher valent bromine is reduced, surpassing the specific capacity and voltage of traditional zinc-bromine batteries, thereby achieving higher energy and power density.

[0038] Beneficial effects

[0039] The present invention innovatively combines a positive electrode containing additive A and an electrolyte containing electrolyte salt B, and further cooperates with additive C and the combined control of the components therein, thereby inducing the formation of a four-electron reaction mechanism and forming a bromide intermetallic compound, improving the stability of the high-valent bromine active substance, and confining it in the positive electrode, effectively inhibiting its dissolution, thereby significantly improving the electrochemical capacity, voltage and coulombic efficiency of the battery based on the said new electrochemical mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 1 is a typical charge and discharge curve diagram of each case of Example 1, Example 2 and Comparative Example 1, wherein Curve 1 is Example 1, Curve 2 is Example 2, and Curve 3 is Comparative Example 1;

[0041] Figure 2 2 are typical charge and discharge curves of Comparative Example 2 and Comparative Example 3, wherein Curve 4 is for Comparative Example 2 and Curve 5 is for Comparative Example 3; DETAILED DESCRIPTION

[0042] The present invention is described below by way of examples.

[0043] In the present invention, the positive electrode may be a coated positive electrode, which comprises a conventional current collector and a positive electrode material loaded on its surface. The positive electrode may also be obtained by slurrying, coating, drying and solidifying the positive electrode material in a conventional manner.

[0044] In the present invention, the positive electrode material contains the additive A and may also contain the additive C. In addition, it may further contain a conductive agent and a binder. The conductive agent and binder may be conventional in the industry.

[0045] In the present invention, the additive A can be at least one substance in the above formula 1 to formula 7, preferably a substance in formula 1. The additive A also needs to provide Br - Or at least one anion among anions a.

[0046] In the present invention, the electrolyte is preferably an aqueous solution containing zinc sulfate and additive C.

[0047] In the present invention, the additive C is allowed to be added to the positive electrode material, is allowed to be added to the electrolyte, and is also allowed to be added to the positive electrode material and the electrolyte at the same time.

[0048] In the present invention, the additives A and C need to provide at least Br - and anions a capable of forming bromide intermetallic compounds, and on this basis, other anions are also allowed to exist.

[0049] In the present invention, the zinc-bromine battery can be a conventional static battery, comprising a battery cell comprising a positive electrode, a separator, and a negative electrode, which are sequentially composited, and an electrolyte in which the battery cell is immersed. The separator, negative electrode, etc. can all be conventional in the industry. For example, in addition to the characteristic statement, as an example embodiment, the separator can be a glass fiber separator, and the negative electrode can be zinc foil.

[0050] Example 1

[0051] Positive electrode material: comprising conductive carbon, binder, additive A and additive C;

[0052] The conductive carbon used was Super P and 1 mm carbon fiber chopped strands (7 μm), with a mass ratio of 3:1, and the total conductive carbon content in the positive electrode material was 15 wt.%.

[0053] The binder is polyacrylamide (Aladdin, Mw 2 million to 14 million), and the binder accounts for 3 wt.% of the weight of the positive electrode material.

[0054] Additive A (Formula 1 (R1 = hexyl; R2 = H, X is Br - )), a mixture of additive C (zinc chloride) in a molar ratio of 1:1, the mixture accounting for 82wt.% of the total mass of the positive electrode;

[0055] The electrolyte is an aqueous solution in which electrolyte salt B (zinc sulfate in this case) is dissolved, and its molar concentration is 3M;

[0056] The negative electrode uses 0.01mm zinc foil from Qingyuan Metal Materials Co., Ltd.

[0057] Figure 1 The charge and discharge curves of the battery are provided (curve 1).

[0058] The zinc-bromine battery assembled by the technical solution of the present invention can generate 100mAg -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity was 657 mAh g-1 according to the mass of bromine.-1 , the median discharge voltage is 1.87V and the Coulomb efficiency is 99.8%.

[0059] Example 2

[0060] Compared with Example 1, the only difference is that the additive A is changed to the substance of formula 7 (Formula 7 (R1~R4 are all ethyl, X is Br - )), and the dosage is the same as in Example 1.

[0061] Figure 1 The charge and discharge curve of the battery is provided (curve 2). -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 421 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.86V and the Coulomb efficiency is 89.5%.

[0062] Example 3

[0063] Compared with Example 1, the only difference is that the type of additive A is changed. The type of additive A is the same as that of Example 1. The experimental groups are:

[0064] Group A: Additive A is of formula 2 (wherein R2 is ethyl, X is Br - , n is 2);

[0065] The assembly test was carried out according to the method of Example 1. The results were as follows: -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 571 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.87V and the Coulomb efficiency is 99.7%.

[0066] Group B: Additive A is of formula 3 (wherein the para position of the pyridine ring is connected to the polyethylene chain, R1 is ethyl, X is Br-, and y is 20000);

[0067] The assembly test was carried out according to the method of Example 1. The results were as follows: -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 544 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.86V and the Coulomb efficiency is 99.5%.

[0068] Group C: Additive A is of formula 4 (wherein, R1 to R2 are ethyl, R3 is H, and X is Br-);

[0069] The assembly test was carried out according to the method of Example 1. The results were as follows: -1The charge and discharge test was carried out at a current density of 1000 mAh g. -1 , the median discharge voltage is 1.87V and the Coulomb efficiency is 95.1%.

[0070] Group D: Additive A is of formula 5 (wherein R1-R2 are ethyl groups, X is Br - , n is 2);

[0071] The assembly test was carried out according to the method of Example 1. The results were as follows: -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity was 545 mAh g-1 according to the mass of bromine. -1 , the median discharge voltage is 1.86V and the coulombic efficiency is 95.5%.

[0072] Group E: Additive A is Formula 6 (wherein R1 is ethyl, X is Br - , y is 50000);

[0073] The assembly test was carried out according to the method of Example 1. The results were as follows: -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity was 528 mAh g-1 according to the mass of bromine. -1 , the median discharge voltage is 1.85V and the Coulomb efficiency is 94.8%.

[0074] Example 4

[0075] Compared with Example 1, the only difference is that the additive C is not added to the positive electrode material, but is added only to the electrolyte, and the amount of the additive C is the same as that in Example 1.

[0076] At room temperature with 100mAg -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 646 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.87V and the Coulomb efficiency is 99.8%.

[0077] Example 5

[0078] Compared with Example 1, the only difference is that the additive C in the positive electrode material is changed to sodium chloride, and the molar amount of the additive C is the same as that in Example 1.

[0079] At room temperature with 100mAg -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity reached 635 mAh g-1 based on the mass of bromine. -1 , the median discharge voltage is 1.86V and the Coulomb efficiency is 99.5%.

[0080] Example 6

[0081] Compared with Example 1, the only difference is that the molar concentration of zinc sulfate in the electrolyte is changed to 1.5M.

[0082] At room temperature with 100mAg -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity reached 436 mAh g-1 based on the mass of bromine. -1 , the median discharge voltage is 1.82V and the Coulomb efficiency is 94.3%.

[0083] Example 7

[0084] Compared with Example 1, the only difference is that the electrolyte salt B in the electrolyte is a mixture of magnesium sulfate and zinc sulfate, and the molar concentrations thereof are 2M and 1M, respectively.

[0085] At room temperature with 100mAg -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 642 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.87V and the Coulomb efficiency is 99.8%.

[0086] Comparative Example 1

[0087] Compared with Example 1, the only difference is that the additive C in the positive electrode material is changed, zinc bromide is used instead of zinc chloride, and the molar amount of zinc bromide is the same as that in Example 1.

[0088] Figure 1 The charge and discharge curve of the battery is provided (curve 3). -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity was 316 mAh g-1 according to the mass of bromine. -1 , the median discharge voltage is 1.67V and the Coulomb efficiency is 99.2%.

[0089] Comparative Example 2

[0090] Compared with Example 1, the only difference is that zinc perchlorate is used in the electrolyte instead of zinc sulfate in equal moles. Other operations and parameters are the same as those in Example 1. The charge and discharge curve is shown in FIG. Figure 2 Curve 1, at room temperature with 100mA g -1 The charge and discharge test was carried out at a current density of 1000 mAh g, and the specific capacity was 344 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.80V and the Coulomb efficiency is 59.9%.

[0091] Comparative Example 3

[0092] Compared with Example 1, the only difference is that zinc nitrate is used in the electrolyte instead of zinc sulfate in an equal molar amount. Other operations and parameters are the same as those in Example 1. The charge and discharge curve is shown in FIG. Figure 2 Curve 2, at room temperature with 100mA g -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity reached 280 mAh g-1 based on the mass of bromine. -1 , the median discharge voltage is 1.59V and the Coulomb efficiency is 67.4%.

[0093] Comparative Example 4

[0094] Compared with Example 1, the only difference is that the additive A is not added to the positive electrode material, but is directly dissolved in the electrolyte, and the amount of additive A is the same as that of Example 1 (the electrolyte of Example 1 is used to dissolve the additive A). -1 The charge and discharge test was carried out at a current density of 1000 nm, and the specific capacity reached 325 mAh g according to the mass of bromine. -1 , the median discharge voltage is 1.65V and the Coulomb efficiency is 94.8%.

Claims

1. A zinc-bromine energy storage battery based on a four-electron conversion reaction, comprising a battery cell in which a positive electrode, a separator and a negative electrode are mutually composited, and an electrolyte for soaking the battery cell, wherein the positive electrode comprises a current collector and a positive electrode material composited on its surface, characterized in that: The positive electrode material comprises at least one additive A in Formula 1 to Formula 7; In Formulae 1 to 7, R1 is a C1-C8 alkyl group, R2-R4 are independently H or a C1-C8 alkyl group; n is 1 to 8; y is 20-1000000; The electrolyte is an aqueous solution containing electrolyte salt B, wherein the cations in the electrolyte salt B at least contain zinc ions; the cations may also contain one or more of sodium, lithium, potassium, magnesium, hydrogen, and guanidine ions; and the anions contain sulfate; The positive electrode material and / or electrolyte may also contain an additive C; the additive C is an electrolyte; The anions of the additive A and the additive C contain at least Br - and an anion a capable of forming a bromide intermetallic compound.

2. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to claim 1, characterized in that: The additive A comprises at least an additive of formula 1; Preferably, the X and anion a are F - , Cl - Br - ,I - 、SCN - ,OTf - TFSI - At least one of .

3. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to claim 1, characterized in that: The additive C is an electrolyte containing at least one cation selected from zinc, sodium, lithium, potassium, magnesium, calcium, aluminum, hydrogen, guanidine ion, and ammonium ion; wherein the anion is preferably F - , Cl - Br - ,I - 、SCN - ,OTf - TFSI - At least one of .

4. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to claim 1, characterized in that: The anion a is F - , Cl - ,I - 、SCN - ,OTf - TFSI - At least one of .

5. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to any one of claims 1 to 4, characterized in that: In the positive electrode material, the content of the additive A is above 20 wt.%, preferably 30 to 70 wt.%.

6. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to claim 5, characterized in that: The positive electrode material may also contain an additive C. Preferably, in the positive electrode material, the weight ratio of the additive C to the additive A is 0.5 to 4:1; Preferably, the positive electrode material further comprises a conductive agent and a binder; Preferably, the binder is a water-soluble polymer, a natural polymer or a mixture thereof, and more preferably at least one of polyacrylamide, polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose and sodium carboxymethyl cellulose; Preferably, the weight content of the binder in the positive electrode material is less than or equal to 15 wt.%; Preferably, the conductive agent is at least one of carbon powder and carbon fiber; the carbon powder is at least one of Super P, acetylene black, carbon nanotubes, graphite, activated carbon, and Ketjen black; the carbon fiber is carbon fiber chopped strands with a length of 0.5 to 12 mm and a diameter of 5 to 10 um, preferably carbon fiber chopped strands with a length of 1 to 3 mm and a diameter of 7 um; Preferably, in the positive electrode material, the content of the conductive agent is less than or equal to 20 wt %, and may further be 5 to 15 wt %.

7. The zinc-bromine energy storage battery based on four-electron conversion reaction according to claim 1, characterized in that: In the electrolyte, the cations in the electrolyte salt B at least include zinc ions; the cations may also include one or more of sodium, lithium, potassium, magnesium, hydrogen, and guanidine ions; the anions are sulfate; Preferably, the concentration of the electrolyte salt B in the electrolyte solution is greater than or equal to 1M, preferably 1 to 15M.

8. The zinc-bromine energy storage battery based on the four-electron conversion reaction according to claim 7, characterized in that: The electrolyte may also contain the additive C; Preferably, the concentration of the additive C in the electrolyte is above 0.1M, and may further be 0.1-2M.

9. The zinc-bromine energy storage battery based on four-electron conversion reaction according to claim 1, characterized in that: The diaphragm is one of a glass fiber membrane, a cellulose membrane, a polytetrafluoroethylene porous membrane, a polypropylene porous membrane, and a polyvinylidene fluoride porous membrane; Preferably, the negative electrode is zinc metal, zinc powder or a carbon material current collector that does not contain metallic zinc.

10. The zinc-bromine energy storage battery based on a four-electron conversion reaction according to any one of claims 1 to 9, characterized in that: The zinc-bromine energy storage battery based on the four-electron conversion reaction refers to the 2Br - -Br2 0 -2Br + A zinc-bromine static battery with a four-electron conversion reaction; Preferably, the zinc-bromine energy storage battery is a zinc-bromine static battery.

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