A zinc-nitrate battery with charge-discharge positive electrode switchable and working method thereof

Abstract

The application discloses a zinc-nitrate battery with switchable charging and discharging anodes and a working method thereof. The zinc-nitrate battery comprises a negative electrode chamber and positive electrode chambers arranged on both sides of the negative electrode chamber. One of the positive electrode chambers is provided with a shape stable anode as a positive electrode in a battery charging process, and the other positive electrode chamber is provided with a catalytic material with catalytic activity for the process of electrochemically reducing nitrate to ammonia as a catalytic positive electrode in a battery discharging process. The negative electrode chamber is provided with metal zinc as a negative electrode in the battery charging and discharging processes. The positive electrode chamber and the negative electrode chamber are separated by an anion exchange membrane. The electrolyte of the positive electrode chamber is an alkaline solution containing nitrate, and the electrolyte of the negative electrode chamber is an alkaline solution containing zinc ions. The positive electrode, the catalytic positive electrode and the negative electrode are respectively led out through wires and connected with double-pole double-throw switches. The double-pole double-throw switches are used for switching the positive electrode and the catalytic positive electrode. The application prevents the catalytic material of the positive electrode from being invalid due to oxidation or dissolution in the charging process, and realizes the functional integration of the zinc-nitrate battery.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage and environmental governance technology, specifically a zinc-nitrate battery with a switchable positive electrode for charging and discharging and its working method. Background Technology

[0002] Aqueous zinc-ion batteries have attracted widespread attention in the field of large-scale energy storage due to their high safety, low cost, and environmental friendliness. Currently, research on cathode materials for aqueous zinc-ion batteries mainly focuses on manganese-based oxides and vanadium-based oxides, while electrolytes mostly use zinc sulfate and zinc acetate systems. Their functions are relatively simple, serving only as ion transport media and failing to endow the battery with additional chemical conversion functions. On the other hand, electrocatalytic nitrate reduction (NO3RR) to ammonia synthesis technology can convert water pollutants such as nitrates into high-value ammonia, but this usually requires a separate three-electrode electrolyzer and lacks integration with energy storage devices. Therefore, if nitrates can be directly introduced into the electrolyte of aqueous zinc-ion batteries, it is hoped that a new type of zinc-nitrate battery can be constructed, simultaneously achieving power output and nitrate reduction to ammonia synthesis during discharge.

[0003] In addition, the cathode catalysts commonly used in aqueous zinc-ion batteries (such as copper-based, cobalt-based, and iron-based catalysts) have become a research hotspot in the NO3RR field due to their low cost and excellent activation ability for nitrate ions. However, existing zinc-nitrate batteries face the problem of cathode material stability during the rechargeable process. This is because such materials are prone to oxidation and dissolution under charging conditions, resulting in poor battery cycle stability and limiting their application in rechargeable batteries. To solve this problem, some studies have attempted to develop corrosion-resistant materials or electrolyte additives, but this often comes at the cost of sacrificing capacity or rate performance.

[0004] Therefore, there is an urgent need to propose a three-electrode rechargeable aqueous zinc-ion battery with nitrate as the electrolyte, which can switch the positive electrode during charging and discharging, thereby retaining the functional integration advantages of the Zn-NO3- battery system while solving the failure problem of conventional positive electrode materials during charging. Summary of the Invention

[0005] The purpose of this invention is to provide a zinc-nitrate battery with a switchable positive electrode for charging and discharging and its working method, which not only prevents the positive electrode catalyst material from failing due to oxidation or dissolution during charging, but also realizes the functional integration of the zinc-nitrate battery.

[0006] This invention is achieved through the following technical solution: A zinc-nitrate battery with switchable charge and discharge positive electrode includes a negative electrode chamber and positive electrode chambers disposed on both sides of the negative electrode chamber. One positive electrode chamber uses a shape-stable anode as the positive electrode during the battery charging process, and the other positive electrode chamber uses a catalytic material with high catalytic activity in the electrochemical reduction of nitrate to ammonia as the catalytic positive electrode during the battery discharging process. The negative electrode chamber uses metallic zinc as the negative electrode during both the battery charging and discharging processes. The positive and negative electrode chambers shown are separated by anion exchange membranes. The electrolyte in the positive electrode chamber is an alkaline solution containing nitrates, and the electrolyte in the negative electrode chamber is an alkaline solution containing zinc ions. The positive electrode, catalytic positive electrode, and negative electrode are each led out through three wires and connected to a double-pole double-throw switch, which switches the positive electrode and catalytic positive electrode.

[0007] Furthermore, the shape-stabilized anode is a ruthenium-iridium-titanium electrode, an iridium electrode, a platinum electrode, a PbO2 electrode, an IrO2 electrode, or a RuO2 electrode.

[0008] Furthermore, the catalytic material with high catalytic activity for the electrochemical reduction of nitrate to ammonia is nickel foam-supported copper oxide nanowires.

[0009] Furthermore, the nickel-foamed copper oxide nanowires supported on copper oxide were prepared by the following method: Step 1: Soak the nickel foam in acetone and dilute hydrochloric acid with a concentration of 3 mol / L for ultrasonic treatment, then rinse repeatedly with deionized water, and then dry to obtain the treated nickel foam. Step 2: Using a three-electrode electrochemical workstation, H3BO3, NiSO4·6H2O and CuSO4·5H2O were used as electrodeposition solutions. A constant voltage of -1.5V vs. SHE was applied to the treated nickel foam surface to perform electrodeposition, resulting in a nickel-copper alloy. Step 3: First, prepare an aqueous solution containing NaOH and (NH4)2S2O8, wherein the concentration of NaOH is 2.5 mol / L and the concentration of (NH4)2S2O8 is 0.5 mol / L; then, immerse the nickel-copper alloy in the aqueous solution containing NaOH and (NH4)2S2O8 and let it stand for 20-30 min to obtain nickel foam loaded with copper hydroxide nanowires. Step 4: Place the nickel foam loaded with copper hydroxide nanowires in a muffle furnace and heat it at 1℃·min under an Ar atmosphere. 1 The temperature was increased from room temperature to 200℃ at a rate of 2 h to obtain nickel foam supported copper oxide nanowires, denoted as CuO NW / NF.

[0010] Furthermore, the alkaline solution containing nitrate is a mixed aqueous solution of nitrate and metal alkali salt, wherein the concentration of nitrate is 0.001~1 mol / L.

[0011] Furthermore, the alkaline solution containing nitrate is a mixed aqueous solution of NaNO3 and NaOH / KOH, wherein the concentration of NaNO3 is 0.01 mol / L and the concentration of NaOH or KOH is 3 mol / L.

[0012] Furthermore, the alkaline solution containing zinc ions is a mixed aqueous solution of soluble zinc salt and metal alkali salt, wherein the concentration of soluble zinc salt is 0.01~5 mol / L and the concentration of metal alkali salt is 1~10 mol / L.

[0013] Furthermore, the alkaline solution containing zinc ions is a mixed aqueous solution of Zn(CH3COO)2 and NaOH / KOH, wherein the concentration of Zn(CH3COO)2 is 0.02 mol / L and the concentration of NaOH or KOH is 3 mol / L.

[0014] Furthermore, the anion exchange membrane is a pretreated FAA-3-50. The pretreatment process is as follows: FAA-3-50 is soaked in a 3% H2O2 solution, deionized water, a 1 mol / L H2SO4 solution, and deionized water for 1 hour each, and then taken out for use.

[0015] A method for operating a zinc-nitrate battery with a switchable positive electrode for charging and discharging includes a discharging process and a charging process, wherein: The discharge process is as follows: A double-pole double-throw switch is used to switch to the catalytic positive electrode, connecting the catalytic positive and negative electrodes to form a discharge circuit. An electrocatalytic reduction reaction of nitrate occurs on the surface of the catalytic positive electrode, and an oxidation reaction of metallic zinc occurs on the surface of the negative electrode. The overall reaction equation for the discharge process is expressed as: During the discharge process, electrons flow from the negative electrode to the catalytic positive electrode through the external circuit, thereby generating a discharge current. OH- is generated in the positive electrode chamber. - Migrating through the anion exchange membrane to the negative electrode chamber, and It is trapped in the positive electrode chamber by the anion exchange membrane; The charging process is as follows: A double-pole double-throw switch is used to switch to the positive electrode, connecting the positive and negative electrodes to form a charging circuit. An oxygen evolution reaction occurs on the surface of the positive electrode, and a zinc deposition reaction occurs on the surface of the negative electrode. The overall reaction formula for the charging process is expressed as: During charging, electrons flow from the positive terminal to the negative terminal through the external circuit, generating a charging current. The negative terminal chamber... Restored to This achieves the regeneration of metallic zinc at the negative electrode and the regeneration of the positive electrode chamber. Consumed and thus produced and , It overflows from the positive electrode chamber.

[0016] The present invention has the following beneficial technical effects: The zinc-nitrate battery assembled in this invention is a three-electrode system, including a positive electrode for charging, a catalytic positive electrode for discharging, and a negative electrode for charging and discharging. During charging and discharging, switching between the discharge circuit and the charging circuit is achieved through a double-pole double-throw switch. During discharge, the catalytic positive electrode catalyzes the nitrate reduction reaction (NO3RR) to generate... Simultaneously, it couples with the negative electrode to output electrical energy; during charging, it connects the stable anode and the negative electrode, and disconnects the catalytic positive electrode and the negative electrode, thereby preventing the catalytic material from failing due to oxidation or dissolution during charging, reducing irreversible phase transitions, and significantly improving the cycle stability of the battery; at the same time, it integrates the three functions of nitrate pollution control, green ammonia electrosynthesis and energy storage into one, realizing the co-production of "water treatment-energy storage-green ammonia synthesis". Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the battery device structure of the present invention; Figure 2 To assemble Zn using nickel foam-supported copper oxide nanowires (CuO NW / NF) NO3 Battery OCP; Figure 3 Zn of the present invention NO3 The battery's discharge curve and power density, as well as the discharge curves at different current densities; Figure 4 Zn of the present invention NO3 Discharge curves of the battery at different current densities; Figure 5 Zn of the present invention NO3 The Faraday efficiency and yield of the battery for the electrocatalytic reduction of nitrate to ammonia at different current densities; Figure 6 Zn of the present invention NO3 Constant current discharge-charge cycle curve of the battery in 50 cycles; Figure 7 Zn of the present invention NO3 The battery is at 10 mA·cm-2 The volt-ampere curve at the current density. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments. These descriptions are for explanation purposes only and are not intended to limit the scope of the invention.

[0019] like Figure 1 As shown, a zinc-nitrate battery with switchable charge and discharge positive electrode includes a negative electrode chamber and positive electrode chambers disposed on both sides of the negative electrode chamber. One positive electrode chamber uses a shape-stable anode as the positive electrode during the battery charging process, and the other positive electrode chamber uses a catalytic material with high catalytic activity in the electrochemical reduction of nitrate to ammonia as the catalytic positive electrode during the battery discharging process. The negative electrode chamber uses metallic zinc as the negative electrode during both the battery charging and discharging processes. That is, when assembling the battery, the catalytic positive electrode and the positive electrode are placed in the two positive electrode chambers respectively, and the zinc negative electrode is placed inside the negative electrode chamber. The positive and negative electrode chambers shown are separated by anion exchange membranes. The electrolyte in the positive electrode chamber is an alkaline solution containing nitrates, and the electrolyte in the negative electrode chamber is an alkaline solution containing zinc ions. The positive electrode, catalytic positive electrode, and negative electrode are each led out through three wires and connected to a double-pole double-throw switch. The positive electrode and catalytic positive electrode are switched by the double-pole double-throw switch, thereby realizing the switching between the discharge circuit and the charging circuit.

[0020] Preferably, the shape-stabilized anode is a ruthenium-iridium-titanium electrode, an iridium electrode, a platinum electrode, a PbO2 electrode, or a noble metal oxide electrode including a PbO2 electrode, an IrO2 electrode, and a RuO2 electrode.

[0021] Preferably, the zinc metal is a zinc sheet or zinc foil with the oxide layer removed from its surface. The process of removing the oxide layer is as follows: first, the surface of the zinc sheet or zinc foil is polished with sandpaper, and then ultrasonically cleaned with anhydrous ethanol and deionized water in sequence to remove the oxide layer on the surface of the zinc sheet or zinc foil.

[0022] Preferably, the catalytic material with high catalytic activity for the electrochemical reduction of nitrate to ammonia is nickel foam-supported copper oxide nanowires, which are prepared by the following method: Step 1: Soak the nickel foam in acetone and dilute hydrochloric acid with a concentration of 3 M respectively for ultrasonic treatment, then rinse repeatedly with deionized water, and then dry to obtain the treated nickel foam. Step 2: Using a three-electrode electrochemical workstation, H3BO3, NiSO4·6H2O and CuSO4·5H2O were used as electrodeposition solutions. A constant voltage of -1.5V vs. SHE was applied to the treated nickel foam surface to perform electrodeposition, resulting in a nickel-copper alloy. Step 3: First, prepare an aqueous solution containing NaOH and (NH4)2S2O8, wherein the concentration of NaOH is 2.5 mol / L and the concentration of (NH4)2S2O8 is 0.5 mol / L; then immerse the nickel-copper alloy in the aqueous solution containing NaOH and (NH4)2S2O8 and let it stand for 20-30 min to obtain nickel foam loaded with copper hydroxide nanowires, denoted as CuO NW / NF.

[0023] Preferably, the alkaline solution containing nitrate is an aqueous solution prepared from nitrate and metal alkali salt, wherein the concentration of nitrate is 0.001~1 mol / L.

[0024] Preferably, the nitrate is NaNO3, and the metal alkali salt is NaOH or KOH. Specifically, the alkaline solution containing nitrate is an aqueous solution prepared from NaNO3 and NaOH / KOH, wherein the concentration of NaNO3 is 0.01 mol / L, and the concentration of NaOH or KOH is 3 mol / L.

[0025] Preferably, the alkaline solution containing zinc ions is a mixed aqueous solution of soluble zinc salt and metal alkali salt, wherein the concentration of soluble zinc salt is 0.01~5 mol / L and the concentration of metal alkali salt is 1~10 mol / L.

[0026] Preferably, the soluble zinc salt is Zn(CH3COO)2, and the metal alkali salt is NaOH or KOH. Specifically, the alkaline solution containing zinc ions is a mixed aqueous solution of Zn(CH3COO)2 and KOH / NaOH, wherein the concentration of Zn(CH3COO)2 is 0.02 mol / L, and the concentration of KOH or NaOH is 3 mol / L.

[0027] Preferably, the anion exchange membrane is a pretreated FAA-3-50, wherein the pretreatment process is as follows: the FAA-3-50 is soaked in a 3% H2O2 solution, deionized water, a 1 mol / L H2SO4 solution, and deionized water for 1 hour each, and then taken out for use.

[0028] A method for operating a zinc-nitrate battery with a switchable positive electrode for charging and discharging includes a discharging process and a charging process, wherein: 1) The discharge process is as follows: A double-pole double-throw switch is used to switch to the catalytic positive electrode, thus connecting the catalytic positive electrode and the negative electrode to form a discharge circuit, wherein: The nitrate electrocatalytic reduction reaction (NO3RR) occurs on the surface of the catalytic cathode, with the chemical formula: The negative electrode surface undergoes a zinc oxidation reaction, with the chemical formula: Therefore, the overall reaction equation for the discharge process is: During the discharge process, electrons flow from the negative electrode to the catalytic positive electrode through the external circuit, thereby generating a discharge current. To maintain charge balance, OH groups generated in the positive electrode chamber... - Migrating through the anion exchange membrane to the negative electrode chamber, and It is trapped in the positive electrode chamber by the anion exchange membrane, and after the discharge is complete, it is detected in the electrolyte in the positive electrode chamber. At a potential of -0.8 V vs. SCE, the ammonia production faradaic efficiency can reach over 80%. 2) The charging process is as follows: After discharging, a double-pole double-throw switch is used to switch to the positive terminal, making the positive and negative terminals conductive to form a charging circuit, wherein: An oxygen evolution reaction occurs on the surface of the positive electrode, with the chemical formula: A zinc deposition reaction occurs on the surface of the negative electrode, with the chemical formula: Therefore, the overall reaction equation for the charging process is expressed as: Without considering When oxidized, the charging process is the reverse of the discharging process. Electrons flow from the positive electrode to the negative electrode through the external circuit, thus generating a charging current. The negative electrode chamber... Restored to This achieves the regeneration of metallic zinc at the negative electrode and the regeneration of the positive electrode chamber. Consumed and thus produced and , The electrolyte overflows from the positive electrode chamber and is regenerated.

[0029] The zinc-nitrate battery with switchable charge / discharge positive electrode provided by this invention completely disconnects the catalytic positive electrode from the negative electrode during charging. This effectively prevents the dissolution or irreversible phase transition of the catalytic material with high catalytic activity in the electrochemical reduction of nitrate to ammonia, thus significantly improving the cycle stability of the battery. Experiments show that the battery of this invention retains more than 85% of its capacity after 50 charge-discharge cycles, while the capacity of a traditional two-electrode battery has decayed to less than 50% after 20 cycles.

[0030] To verify the performance of the zinc-nitrate battery with switchable charge / discharge positive electrode proposed in this invention, a zinc-nitrate battery was assembled for testing: Nickel foam-supported copper oxide nanowire material (CuO NW / NF) was used as the catalytic positive electrode during battery discharge; a mixed aqueous solution of NaNO3 and KOH (NaNO3 concentration 0.01 mol / L, KOH concentration 3 mol / L) was used as the electrolyte in the positive electrode chamber; a 2 cm × 3 cm zinc sheet was selected and polished to serve as the negative electrode; a mixed aqueous solution of Zn(CH3COO)2 and KOH (Zn(CH3COO)2 concentration 0.02 mol / L, KOH concentration 3 mol / L) was used as the electrolyte in the negative electrode chamber; a ruthenium-iridium-titanium plate was used as the positive electrode during battery charging; the positive and negative electrode chambers were separated by a pretreated anion exchange membrane (FAA-3-50); during battery assembly, nitrogen gas was introduced into both the positive and negative electrode chambers for 30 minutes. min to remove oxygen from the electrolyte.

[0031] The assembled zinc-nitrate batteries were subjected to charge-discharge tests, which were conducted using a LAND CT2001A battery testing system at room temperature. Constant current discharge (current density 1~30 mA·cm⁻¹) was used during the charge-discharge process. -2 The discharge cutoff potential is -0.2 V vs. Zn. 2+ / Zn, the charging cutoff potential is 1.8 V vs. Zn 2+ / Zn; During charging and discharging, record the battery's discharge capacity, charging capacity, coulombic efficiency, and cycle stability, including: 1) Cycle life test: at 1 mA·cm - 2) Repeated charge-discharge cycles at the current density for more than 50 cycles, recording the discharge capacity decay in each cycle; 2) Rate performance test: At a discharge current density of 2 mA·cm⁻¹ -2 4 mA·cm -2 6 mA·cm -2 8 mA·cm -2 10 mA·cm -2 and 12 mA·cm -2 Constant current discharge tests were conducted, with the charging current density maintained consistent with the discharge current, to examine the capacity retention and voltage plateau changes of the battery at different rates; 3) Ammonia production determination: After discharge, electrolyte from the positive electrode chamber was taken, and the ammonia nitrogen content was determined using ion chromatography or indophenol blue colorimetry, and the Faraday efficiency was calculated; for specific test results, please refer to [link to relevant documentation]. Figures 2-7 ; See Figure 2 The assembled zinc-nitrate battery has an open-circuit potential (OCP) of 1.125 V. See Figure 3At 10 mA·cm -2 At the discharge current, the discharge voltage is +0.88 V, and at 0.44 V vs Zn 2+ At the specified voltage, a maximum power density of 13.18 mW·cm⁻¹ was obtained. -2 ; See Figure 4 Current density from 2 mA·cm -2 Stepwise increase to 24 mA·cm -2 During the process, a stable voltage plateau was observed at each rate, and the voltage decay was approximately linearly related to the current density, indicating that the battery internal resistance was relatively stable. See Figure 5 , in the range of 5~25 mA·cm -2 Within the current density range, the yield of ammonia increases with increasing current density, especially at a current density of 10 mA·cm⁻¹. -2 At that time, the ammonia Faraday efficiency in the NO3RR electrocatalytic process at the catalytic cathode reached 84.5%; See Figure 6 The battery maintained a very small voltage drop during 50 charge-discharge cycles, demonstrating good stability. See Figure 7 At 10 mA·cm -2 At a current density of 280 mV, the overpotential of the ruthenium-iridium-titanium electrode is only 280 mV.

Claims

1. A zinc-nitrate battery with a switchable positive electrode for charging and discharging, characterized in that, It includes a negative electrode chamber and positive electrode chambers disposed on both sides of the negative electrode chamber. One positive electrode chamber uses a shape-stable anode as the positive electrode in the battery charging process, and the other positive electrode chamber uses a catalytic material with high catalytic activity in the electrochemical reduction of nitrate to ammonia as the catalytic positive electrode in the battery discharging process. The negative electrode chamber uses metallic zinc as the negative electrode in both the battery charging and discharging processes. The positive and negative electrode chambers shown are separated by anion exchange membranes. The electrolyte in the positive electrode chamber is an alkaline solution containing nitrates, and the electrolyte in the negative electrode chamber is an alkaline solution containing zinc ions. The positive electrode, catalytic positive electrode, and negative electrode are led out through wires and connected to a double-pole double-throw switch, and the positive electrode and catalytic positive electrode are switched by the double-pole double-throw switch.

2. The zinc-nitrate battery with switchable charge / discharge positive electrode according to claim 1, characterized in that, The shape-stabilized anode is a ruthenium-iridium-titanium electrode, an iridium electrode, a platinum electrode, a PbO2 electrode, an IrO2 electrode, or a RuO2 electrode.

3. The zinc-nitrate battery with switchable charge / discharge positive electrode according to claim 1, characterized in that, The catalytic material with high catalytic activity for the electrochemical reduction of nitrate to ammonia is nickel foam-supported copper oxide nanowires.

4. The zinc-nitrate battery with switchable charge / discharge positive electrode according to claim 3, characterized in that, The nickel foam-supported copper oxide nanowires were prepared by the following method: Step 1: Soak the nickel foam in acetone and dilute hydrochloric acid with a concentration of 3 mol / L for ultrasonic treatment, then rinse repeatedly with deionized water, and then dry to obtain the treated nickel foam. Step 2: Using a three-electrode electrochemical workstation, H3BO3, NiSO4·6H2O and CuSO4·5H2O were used as electrodeposition solutions. A constant voltage of -1.5V vs. SHE was applied to the treated nickel foam surface to perform electrodeposition, resulting in a nickel-copper alloy. Step 3: First, prepare an aqueous solution containing NaOH and (NH4)2S2O8, wherein the concentration of NaOH is 2.5 mol / L and the concentration of (NH4)2S2O8 is 0.5 mol / L; then, immerse the nickel-copper alloy in the aqueous solution containing NaOH and (NH4)2S2O8 and let it stand for 20-30 min to obtain nickel foam loaded with copper hydroxide nanowires. Step 4: Place the nickel foam loaded with copper hydroxide nanowires in a muffle furnace and heat it at 1℃·min under an Ar atmosphere. 1 The temperature was increased from room temperature to 200℃ at a rate of 2 h to obtain nickel foam supported copper oxide nanowires, denoted as CuO NW / NF.

5. The zinc-nitrate battery with switchable charge / discharge positive electrode according to any one of claims 1 to 4, characterized in that, The alkaline solution containing nitrate is a mixed aqueous solution of nitrate and metal alkali salt, wherein the concentration of nitrate is 0.001~1 mol / L.

6. The zinc-nitrate battery with switchable charge / discharge positive electrode according to claim 5, characterized in that, The alkaline solution containing nitrate is a mixed aqueous solution of NaNO3 and NaOH / KOH, wherein the concentration of NaNO3 is 0.01 mol / L and the concentration of NaOH or KOH is 3 mol / L.

7. The zinc-nitrate battery with switchable charge / discharge positive electrode according to any one of claims 1 to 4, characterized in that, The alkaline solution containing zinc ions is a mixed aqueous solution of soluble zinc salt and metal alkali salt, wherein the concentration of soluble zinc salt is 0.01~5 mol / L and the concentration of metal alkali salt is 1~10 mol / L.

8. The zinc-nitrate battery with switchable charge / discharge positive electrode according to claim 7, characterized in that, The alkaline solution containing zinc ions is a mixed aqueous solution of Zn(CH3COO)2 and NaOH / KOH, wherein the concentration of Zn(CH3COO)2 is 0.02 mol / L and the concentration of NaOH or KOH is 3 mol / L.

9. The zinc-nitrate battery with switchable charge / discharge positive electrode according to any one of claims 1 to 4, characterized in that, The anion exchange membrane is a pretreated FAA-3-50. The pretreatment process is as follows: FAA-3-50 is soaked in a 3% H2O2 solution, deionized water, a 1 mol / L H2SO4 solution, and deionized water for 1 hour each, and then taken out for use.

10. A method for operating a zinc-nitrate battery with a switchable charge / discharge positive electrode as described in claim 1, characterized in that, It includes the discharge process and the charging process, wherein: The discharge process is as follows: A double-pole double-throw switch is used to switch to the catalytic positive electrode, connecting the catalytic positive and negative electrodes to form a discharge circuit. An electrocatalytic reduction reaction of nitrate occurs on the surface of the catalytic positive electrode, and an oxidation reaction of metallic zinc occurs on the surface of the negative electrode. The overall reaction equation for the discharge process is expressed as: During the discharge process, electrons flow from the negative electrode to the catalytic positive electrode through the external circuit, thereby generating a discharge current. OH- is generated in the positive electrode chamber. - Migrating through the anion exchange membrane to the negative electrode chamber, and It is trapped in the positive electrode chamber by the anion exchange membrane; The charging process is as follows: A double-pole double-throw switch is used to switch to the positive electrode, connecting the positive and negative electrodes to form a charging circuit. An oxygen evolution reaction occurs on the surface of the positive electrode, and a zinc deposition reaction occurs on the surface of the negative electrode. The overall reaction formula for the charging process is expressed as: During charging, electrons flow from the positive terminal to the negative terminal through the external circuit, generating a charging current. The negative terminal chamber... Restored to This achieves the regeneration of metallic zinc at the negative electrode and the regeneration of the positive electrode chamber. Consumed and thus produced and , It overflows from the positive electrode chamber.

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