A low-concentration electrolyte containing non-corrosive organic halide and its application in zinc-iodine battery

Abstract

The application belongs to the technical field of batteries, and discloses a low-concentration electrolyte containing non-corrosive organic halide and application of the electrolyte in a zinc-iodine battery. The electrolyte comprises zinc sulfate, deionized water and organic halide; the molar ratio of zinc sulfate to organic halide is 3:(0.3-1); and the organic halide is one or more of 2-bromoacetamide, 2-bromopropionamide and 3-bromopropionamide. The organic halide can activate I 0 / I + a redox pair, form a new type of chemical bond (C-Br-I) between organic halides different from the previous I-Br bond, and have faster kinetics, and significantly inhibit the hydrolysis and shuttling of the compound between organic halides under low-concentration conditions. The application avoids the problems of high cost, point corrosion of the zinc negative electrode and slow iodine conversion kinetics caused by the viscous electrolyte in the previous high-concentration halogen ion electrolyte, and significantly improves the energy density, power density and cycle life of the four-electron iodine conversion type zinc-iodine battery, and has good practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a low-concentration electrolyte containing non-corrosive organic halides and application thereof in zinc-iodine batteries. Background Art

[0002] Large-scale grid-connected utilization of renewable energy is a key component in achieving carbon neutrality. Compared to the currently widely used pumped storage technology, the spatiotemporal flexibility of electrochemical energy storage better accommodates the intermittent nature of renewable energy generation, making it crucial for large-scale energy storage applications. Currently, commercial organic lithium-ion batteries still dominate large-scale electrochemical energy storage. However, limited lithium reserves and safety concerns associated with the use of flammable organic electrolytes are increasingly exposing their limitations in large-scale energy storage applications.

[0003] Low-cost, high-safety aqueous zinc batteries are a new electrochemical energy storage technology that has emerged in recent years and are highly anticipated for large-scale energy storage applications. However, traditional insertion and removal type positive electrodes (manganese and vanadium oxides) have low voltages (below 1.4V) and low capacities (less than 300mA hg -1 ), resulting in the overall battery energy density being less than ideal (100Wh kg -1 In contrast, the use of iodine conversion type positive electrode with variable valence can achieve both high capacity and high energy density of the battery. In particular, when I - / I 0 and I 0 / I + When both redox pairs are excited, a four-electron transfer process can be achieved, and a high current of 422.2 mA hg -1 The specific capacity and 420Wh kg -1 energy density. In this process, the high voltage I 0 / I + The redox couple contributes more than half of the capacity and energy density. - / I 0 Based on the redox pair, the excitation I 0 / I + Redox pairs have very important practical value.

[0004] In previous studies, high-valence I 0 / I + Redox couple excitation usually requires the use of a high concentration of halogen ions (Br - 、Cl - ) electrolyte. Although this type of electrolyte can stimulate and stabilize I +However, their high viscosity and low ionic conductivity significantly affect the battery reaction kinetics. In particular, these electrolytes are often extremely corrosive, causing the zinc anode to rapidly degrade due to severe pitting corrosion. These factors have seriously hindered the practical application of four-electron iodine conversion zinc-iodine batteries. Summary of the Invention

[0005] Based on the problems existing in the above background technology, the present invention provides a low-concentration electrolyte containing non-corrosive organic halides, which activates I by means of the C-Br bond in the additive. 0 / I + Redox pairs form C-Br-I chemical bonds, which stimulate and stabilize I 0 / I + The effect of redox couple enables the battery to maintain I for a long time at high current density 0 / I + The capacity contribution of the redox couple is improved, thereby obtaining a zinc-iodine battery with high specific energy, high specific power and long life.

[0006] Another object of the present invention is to provide a method for preparing the above-mentioned low-concentration electrolyte containing non-corrosive organic halides.

[0007] Another object of the present invention is to provide a four-electron iodine conversion zinc-iodine battery assembled based on the low-concentration electrolyte containing organic halides, wherein the positive electrode can excite reversible I - / I 0 and I 0 / I + Redox couple.

[0008] The purpose of the present invention is achieved through the following technical solutions:

[0009] A low-concentration electrolyte containing non-corrosive organic halide comprises zinc sulfate, deionized water and organic halide; the molar ratio of the zinc sulfate to the organic halide is 3:(0.3-1); and the organic halide is one or more of 2-bromoacetamide, 2-bromopropionamide or 3-bromopropionamide.

[0010] Preferably, the concentration of the electrolyte is greater than 0 and less than or equal to 5 mol / L.

[0011] The method for preparing the low-concentration electrolyte containing non-corrosive organic halides comprises the following specific steps:

[0012] S1. Zinc sulfate was added to deionized water and stirred at room temperature to prepare a zinc sulfate solution;

[0013] S2. Add an organic halide to a zinc sulfate solution and stir at room temperature to prepare a low-concentration electrolyte containing a non-corrosive organic halide.

[0014] Preferably, the stirring time in step S1 is 1 to 2 hours, and the stirring time in step S2 is 2 to 4 hours.

[0015] A four-electron iodine conversion type zinc-iodine battery comprises a positive electrode, a negative electrode, a diaphragm and a low-concentration electrolyte containing a non-corrosive organic halide.

[0016] Preferably, the positive electrode is an iodine composite material encapsulated by activated carbon, the negative electrode is a zinc metal sheet, and the separator is glass fiber.

[0017] Preferably, the activated carbon-encapsulated iodine composite material is activated carbon and iodine element supported thereon.

[0018] The present invention is the first to use a low-concentration zinc sulfate electrolyte (0-5 mol / L) containing a non-corrosive organic halide additive (2-bromoacetamide, 2-bromopropionamide or 3-bromopropionamide) to replace the previous high-concentration halogen ion electrolyte (15-30 mol / L). The electrolyte does not contain highly corrosive free halogen ions (Br - or Cl - ), which stimulates I 0 / I + The redox couple relies on a C-Br-I chemical bond, rather than a conventional IX (X=Br, Cl) interhalogen compound, to form. Compared to conventional interhalogen bonds, the C-Br-I bond exhibits faster kinetics and is less susceptible to hydrolysis and the shuttle effect. As a result, the assembled four-electron zinc-iodine battery achieves high energy density, high power density, and long cycle life, providing a novel solution for the development of four-electron iodine conversion zinc-iodine batteries.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention is the first in the industry to propose the use of organic halogen chemical bonds (C-Br-I) to stimulate high voltage I 0 / I + Redox couple, and with conventional I - / I 0 The redox pair combines to form a high-capacity four-electron iodine conversion zinc-iodine battery. Compared with the previous I based on conventional halogen chemical bond excitation 0 / I + Redox couple, dependent on I excited by C-Br-I 0 / I + The redox couple has faster reaction kinetics, and the formed organic halogen compounds are less susceptible to hydrolysis and shuttle effects in low-concentration electrolytes.

[0021] 2. The low-concentration electrolyte containing non-corrosive organic halides of the present invention is lower in cost, less corrosive, and has higher ionic conductivity than conventional aqueous electrolytes containing high-concentration halogen ions. This avoids the severe pitting corrosion of the zinc negative electrode by the high-concentration halogen ion aqueous electrolyte, which leads to its rapid degradation.

[0022] 3. The present invention optimizes the ratio of zinc sulfate and organic halide additives in the electrolyte to achieve a four-electron iodine conversion zinc iodine battery at a super high rate (60A g -1 ) charge and discharge under the condition of 40Ag, which significantly improved the energy density and energy efficiency of the four-electron iodine conversion zinc-iodine battery under fast charge conditions; -1 Under high current density, a long life of more than 16,000 cycles can be achieved, which is conducive to reducing battery use costs; the optimized electrolyte can support a high loading capacity (24mg cm) far exceeding the current industry reports. -2 ) The iodine positive electrode realizes four-electron conversion, and I 0 / I + The high-voltage discharge platform capacity contributed by the redox couple can be maintained at around 48%, which helps to obtain high-energy single cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The relationship between viscosity and ionic conductivity and concentration of Comparative Example 3 and Example 1 as well as the high-concentration salt electrolyte reported in the current industry;

[0024] Figure 2 The cost comparison chart of Comparative Example 1, Comparative Example 3, Examples 1-3, and a high-concentration salt electrolyte system (above 10 mol / L) is shown;

[0025] Figure 3 is the Tafel curve of zinc negative electrode in different electrolytes;

[0026] Figure 4 High-definition digital photos of the battery shell and zinc sheet after 500 cycles of zinc-iodine batteries assembled using the electrolytes in Application Example 1 and Comparative Examples 1 and 3;

[0027] Figure 5 The cycling performance of Zn / / Zn symmetrical cells assembled using the three electrolytes in Comparative Examples 1, 3 and Example 1 is shown;

[0028] Figure 6 Cyclic voltammetry curves of zinc-iodine batteries assembled using the electrolytes in Comparative Examples 1-3 and Application Examples 1-3;

[0029] Figure 7 The charge transfer activation energy of zinc-iodine batteries assembled using the electrolytes in Application Example 1 and Comparative Example 3 respectively;

[0030] Figure 8High-definition digital photos of zinc-iodine batteries assembled using the electrolytes in Application Example 1 and Comparative Example 3 after one cycle of charge and discharge in a beaker battery;

[0031] Figure 9 The rate performance of zinc-iodine batteries assembled using the electrolytes in Application Example 1 and Comparative Example 3 is shown;

[0032] Figure 10 The charge and discharge curves of zinc-iodine batteries assembled using the electrolytes in Application Example 1 and Comparative Example 3 at different currents are shown;

[0033] Figure 11 The electrolytes in Application Example 1 and Comparative Examples 1 and 3 are used to assemble zinc-iodine batteries at 2Ag -1 Cycling performance at different current densities;

[0034] Figure 12 To assemble zinc-iodine battery with the electrolyte in Application Example 1 at 20Ag -1 and 40Ag -1 Cycling performance at different current densities;

[0035] Figure 13 To investigate the rate performance of zinc-iodine batteries assembled using the electrolyte in Application Example 1 at different iodine loadings;

[0036] Figure 14 The charge and discharge curves of the zinc-iodine battery assembled with the electrolyte in Application Example 1 under high iodine loading;

[0037] Figure 15 The zinc-iodine battery assembled with the electrolytes in Application Example 1 and Comparative Example 3 was tested at a high iodine loading (14.65 mg cm -2 ) under the cycle performance;

[0038] Figure 16 This is a comparison of the iodine positive electrode loading of zinc-iodine batteries assembled using application example 1 and high-concentration salt electrolytes currently used in the industry. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0040] Example 1

[0041] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0042] 2. Add 0.097 g of 2-bromoacetamide to the above zinc sulfate solution and stir at room temperature for 2 to 4 hours to prepare an aqueous electrolyte containing 2-bromoacetamide, wherein the concentration of 2-bromoacetamide is 0.7 mol / L.

[0043] Example 2

[0044] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0045] 2. Add 0.106 g of 2-bromopropionamide to the above zinc sulfate solution, stir at room temperature for 2 to 4 hours, and take the supernatant to prepare an aqueous low-concentration electrolyte containing 2-bromopropionamide, wherein the concentration of 2-bromopropionamide is 0.7 mol / L.

[0046] Example 3

[0047] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0048] 2. Add 0.106 g of 3-bromopropionamide to the above zinc sulfate solution, stir at room temperature for 2 to 4 hours, and take the supernatant to prepare an aqueous low-concentration electrolyte containing 3-bromopropionamide, wherein the concentration of 3-bromopropionamide is 0.7 mol / L.

[0049] Comparative Example 1

[0050] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0051] 2. At room temperature, a supercapacitor activated carbon-encapsulated iodine composite material (I@AC), acetylene black (Super P) conductive additive, and sodium carboxymethyl cellulose binder (CMC aqueous solution) in a mass ratio of 8:1:1 were ground and thoroughly mixed to form a slurry. The slurry was then coated on a carbon cloth current collector and dried to produce the I@AC electrode.

[0052] 3. Use the obtained zinc sulfate solution as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode to assemble a zinc-iodine battery, abbreviated as ZSO.

[0053] Comparative Example 2

[0054] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0055] 2. Add 0.041 g of acetamide to the above zinc sulfate solution and stir at room temperature for 2 to 4 hours to prepare an aqueous low-concentration electrolyte containing 0.7 mol / L acetamide.

[0056] 3. At room temperature, an aqueous solution of I@AC, Super P, and CMC in a mass ratio of 8:1:1 was ground and thoroughly mixed to form a slurry, which was then applied to a carbon cloth current collector and dried to obtain an I@AC electrode.

[0057] 4. A zinc-iodine battery (abbreviated as Ace) was assembled using the resulting low-concentration aqueous electrolyte containing acetamide as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode. Comparative Example 2 does not contain halogen and cannot activate the four-electron reaction, eliminating interference from the amide group.

[0058] Comparative Example 3

[0059] 1. Add 0.863 g of zinc sulfate to 1 mL of deionized water and stir at room temperature for 2 h to prepare a 3 mol / L zinc sulfate solution.

[0060] 2. Add 0.079 g zinc bromide to the above zinc sulfate solution and stir at room temperature for 2 to 4 hours to prepare an aqueous low-concentration electrolyte containing 0.7 mol / L zinc bromide.

[0061] 3. At room temperature, an aqueous solution of I@AC, Super P, and CMC in a mass ratio of 8:1:1 was ground and thoroughly mixed to form a slurry, which was then applied to a carbon cloth current collector and dried to obtain an I@AC electrode.

[0062] 4. Using the obtained low-concentration aqueous electrolyte containing zinc bromide as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode, a zinc-iodine battery is assembled, abbreviated as ZnBr2.

[0063] Application Example 1

[0064] 1. Activated carbon and iodine powder in a mass ratio of 1:1 were fully ground to prepare I@AC composite material.

[0065] 2. At room temperature, a solution of I@AC, Super P, and CMC in a mass ratio of 8:1:1 was ground and thoroughly mixed to form a slurry. The slurry was then applied to a carbon cloth current collector and dried to produce the I@AC electrode.

[0066] 3. At room temperature, a zinc-iodine battery (abbreviated as BrAce) was assembled using the aqueous low-concentration electrolyte containing organic halides obtained in Example 1 as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode.

[0067] Application Example 2

[0068] 1. Activated carbon and iodine powder in a mass ratio of 1:1 were fully ground to prepare I@AC composite material.

[0069] 2. At room temperature, a solution of I@AC, Super P, and CMC in a mass ratio of 8:1:1 was ground and thoroughly mixed to form a slurry. The slurry was then applied to a carbon cloth current collector and dried to produce the I@AC electrode.

[0070] 3. At room temperature, a zinc-iodine battery (abbreviated as 2-BrPace) was assembled using the aqueous low-concentration electrolyte containing the organic halide additive obtained in Example 2 as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode.

[0071] Application Example 3

[0072] 1. Activated carbon and iodine powder in a mass ratio of 1:1 were fully ground to prepare I@AC composite material.

[0073] 2. At room temperature, a solution of I@AC, Super P, and CMC in a mass ratio of 8:1:1 was ground and thoroughly mixed to form a slurry. The slurry was then applied to a carbon cloth current collector and dried to produce the I@AC electrode.

[0074] 3. At room temperature, a zinc-iodine battery (abbreviated as 3-BrPace) was assembled using the aqueous low-concentration electrolyte containing the organic halide additive obtained in Example 3 as the electrolyte, the I@AC electrode as the positive electrode, and the metal zinc sheet as the negative electrode.

[0075] Figure 1 The relationship between the viscosity and ionic conductivity of high-concentration salt electrolyte reported in Example 1, Comparative Example 3 and the concentration is shown in Table 1. Figure 1 It can be seen that the aqueous electrolyte containing 2-bromoacetamide in Example 1 has low viscosity and high ion conductivity, and has good application prospects. Figure 2 The figure is a cost comparison chart of comparative examples 1 and 3 and embodiments 1-3 and a high-concentration salt electrolyte system. Figure 2 It can be seen that compared with traditional high-concentration salt electrolytes, Example 1 has lower costs and has good commercial prospects.

[0076] Figure 3 The Tafel curves of zinc negative electrode in different electrolytes are shown in Figure 2, with a scan rate of 1 mV s. -1 .Depend on Figure 3 It can be seen that compared with Comparative Examples 1 and 3, the corrosion potential of the zinc negative electrode in Example 1 is more positive and the corrosion current is smaller, indicating that the low-concentration aqueous electrolyte containing non-corrosive organic halide additives is more conducive to reducing the corrosion of the zinc negative electrode. Figure 4 This is a high-definition digital photo of the zinc sheet negative electrode after 500 electrochemical cycles of the zinc-iodine battery assembled in Application Example 1 and Comparative Example 3. Figure 4It can be seen that the zinc sheet of Comparative Example 3 has extremely serious pitting corrosion and has been perforated, while the zinc sheet of Application Example 1 is relatively intact, indicating that the use of a low-concentration electrolyte containing a non-corrosive organic halide additive avoids the problem of conventional electrolytes containing free Br. - Effect of aqueous electrolyte on pitting corrosion of zinc sheet negative electrode.

[0077] Figure 5 The cycling performance of Zn / / Zn symmetrical batteries assembled using the three electrolytes in Comparative Examples 1 and 3 and Example 1, the areal current density and areal capacity are 5 mA cm -2 and 1mAh cm -2 .Depend on Figure 5 It can be seen that compared with Comparative Examples 1 and 3, the Zn / / Zn symmetrical battery using the non-corrosive low-concentration electrolyte in Example 1 exhibits lower polarization and longer cycle life. Figure 6 For Application Examples 1-3 and Comparative Examples 1-3 at 1mV s -1 Cyclic voltammetry curves at different scan rates. Figure 6 It can be seen that the comparative example 3 and application examples 1-3 all showed the corresponding 0 / I + The redox peak of the conversion was not found in Comparative Examples 1-2, indicating that the free Br - Both organic bromides can activate I 0 / I + Compared with Comparative Example 3, the corresponding 1 in Application Example 1 0 / I + The redox peak current of the conversion is higher, and there is no Br2 precipitation, which means that organic bromide is more conducive to the excitation of I 0 / I + conversion, and the electrochemical stability of the additive itself within the same voltage window can be guaranteed.

[0078] Figure 7 The charge transfer activation energy of the zinc-iodine battery assembled with the electrolyte in Application Example 1 and Comparative Example 3 was calculated using the Arrhenius equation. Figure 7 It can be seen that compared with Comparative Example 3, the charge transfer activation energy of Application Example 1 is lower and the kinetics is faster. Figure 8 This is a digital photo of the zinc-iodine battery assembled with the electrolytes in Application Example 1 and Comparative Example 3 after one cycle of charge and discharge in a beaker battery. Figure 8 It can be seen that compared with Comparative Example 3, the electrolyte in Application Example 1 has no obvious color change, indicating that the organic halide additive can effectively inhibit the shuttling of charge and discharge active products.

[0079] Figure 9 The rate performance of the zinc-iodine battery assembled with the electrolytes in Application Example 1 and Comparative Example 3 is shown. Figure 9It can be seen that the rate performance of Application Example 1 is much better than that of Comparative Example 3. -1 At current densities of 100,000, the battery capacities are 355, 342, 331, 310, 287, 264, 233, 221, and 180 mA h g -1 . Figure 10 The charge and discharge curves of the zinc-iodine battery assembled with the electrolytes in Application Example 1 and Comparative Example 3 at different current densities are shown. Figure 10 It can be seen that even at 60A g -1 Under the ultra-high current density, the stimulating effect of the organic halide additive on iodine conversion in Application Example 1 can still be maintained.

[0080] Figure 11 The zinc-iodine battery assembled with the electrolyte in Application Example 1 and Comparative Examples 1 and 3 is 2Ag -1 Cycling performance diagram under current density. Figure 11 It can be seen that the capacity retention rate of Application Example 1 is as high as 90% after 2000 cycles, while the capacity retention rate of Comparative Example 3 is only 50.3% after 2000 cycles. This shows that the cycle stability of Application Example 1 is much better than that of Comparative Example 3. Figure 12 The zinc-iodine battery assembled with the electrolyte in Application Example 1 was tested at 20A g -1 and 40A g -1 Cycling performance under current density. Figure 12 It can be seen that in application example 1, -1 and 40Ag -1 Under high current density, they can stably cycle for 8000 and 16000 cycles respectively.

[0081] Figure 13 The figure shows the rate performance of the zinc-iodine battery assembled with the electrolyte in Application Example 1 at different iodine loadings. Figure 13 It can be seen that in Application Example 1, even at 24 mg cm -2 It still has excellent rate performance under high iodine loading, showing good application prospects. Figure 14 The charge and discharge curves of the zinc-iodine battery assembled with the electrolyte in Application Example 1 under high iodine loading are shown. It can be seen that even at 9.8 mg cm -2 Even at high iodine loading, Application Example 1 can still maintain sufficient four-electron reversible conversion reaction. Figure 15 The zinc-iodine battery assembled with the electrolytes in Application Example 1 and Comparative Example 3 was tested at a high iodine loading (14.65 mg cm -2 ) under the cycle performance diagram. Figure 15 It can be seen that the high-load battery assembled in Comparative Example 3 failed after 7 cycles of activation, while the high-load zinc-iodine battery assembled in Application Example 1 can provide up to 3.9 mAh cm -2The capacity can be cycled stably for 400 times without attenuation. Figure 16 The figure is a comparison chart of iodine loading mass compatible with Application Example 1 and high-concentration salt electrolyte system. Figure 16 It can be seen that Application Example 1 is as high as 24 mg cm -2 The iodine loading capacity is compatible with that of the conventional zinc-iodine battery, far exceeding the relevant results of the four-electron iodine conversion type zinc-iodine battery currently reported in the industry.

[0082] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A low-concentration electrolyte containing a non-corrosive organic halide, characterized in that: The electrolyte includes zinc sulfate, deionized water and an organic halide; the molar ratio of the zinc sulfate to the organic halide is 3:(0.3~1); the organic halide is one or more of 2-bromoacetamide, 2-bromopropionamide or 3-bromopropionamide; and the concentration of the electrolyte is greater than 0 and less than or equal to 5 mol / L.

2. The method for preparing a low-concentration electrolyte containing a non-corrosive organic halide according to claim 1, wherein: The specific steps include: S1. Zinc sulfate was added to deionized water and stirred at room temperature to obtain a zinc sulfate solution; S2. Add an organic halide to a zinc sulfate solution and stir at room temperature to prepare a low-concentration electrolyte containing a non-corrosive organic halide.

3. The method for preparing a low-concentration electrolyte containing a non-corrosive organic halide according to claim 2, wherein: The stirring time in step S1 is 1 to 2 h, and the stirring time in step S2 is 2 to 4 h.

4. A four-electron iodine conversion zinc-iodine battery, characterized in that: The zinc-iodine battery comprises a positive electrode, a negative electrode, a separator and the low-concentration electrolyte containing non-corrosive organic halide according to claim 1.

5. The four-electron iodine conversion zinc-iodine battery according to claim 4, characterized in that: The positive electrode is an iodine composite material encapsulated by activated carbon, the negative electrode is a zinc metal sheet, and the diaphragm is glass fiber.

6. The four-electron iodine conversion zinc-iodine battery according to claim 5, characterized in that: The activated carbon-encapsulated iodine composite material comprises activated carbon and iodine element loaded thereon.

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