An alkaline high-valence iodine solution flow battery with capacity adjustable according to light intensity for large-scale energy storage.

Abstract

An alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage is disclosed. The purpose of this invention is to address the issues of reduced battery life and capacity caused by the precipitation of elemental iodine in current acidic and neutral iodine flow batteries by forming iodate and periodate salts. The alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage comprises a stack consisting of one or more single cells. Each single cell includes a positive electrolyte, a negative electrolyte, two light-proof storage tanks, a fixed end plate with a quartz window, a current collector fixed end plate with an S-shaped flow channel, a gasket, an ion sieving membrane, a positive electrode, a negative electrode, and a photocatalytic material. This invention provides an alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for long-term large-scale energy storage. This flow battery is compatible with multiple charge / discharge modes and can be quickly adjusted to accommodate fluctuations in the energy to be stored.

Description

Technical Field

[0001] This invention relates to an iodine solution flow battery. Background Technology

[0002] Iodine is abundant in the ocean, inexpensive, and possesses high energy density, fast reaction kinetics, and good reversibility, making it one of the most promising active materials for redox energy storage. Therefore, iodine is increasingly being incorporated into battery design, combined with metal anodes (such as lithium and zinc) to create various single-flow batteries for sustainable energy storage. However, existing iodine batteries involve the generation of large amounts of elemental iodine during charging and discharging. The precipitated elemental iodine has low solubility in aqueous solutions, which can cause pipe blockage and capacity decay. Furthermore, the metal anodes used in metal / iodine flow batteries are expensive for large-scale energy storage and pose a risk of metal dendrite formation and metal oxide precipitation on the electrode surface during long cycles.

[0003] Iodine can exist stably in aqueous solutions in valence states of -1, 0, +5, and +7, while current research on iodine flow batteries mainly focuses on I3 under acidic conditions. - and I - This redox pair, where a single iodine ion stores a single electron, does not utilize the higher oxidation states of iodine. This is mainly limited by the electrode selection in current iodine flow batteries and the excessively high activation overpotential required for iodine to transition from a low oxidation state to a +5 or +7 oxidation state due to the low electrolyte pH. Therefore, the application of high-valence iodine in flow batteries is a direction worth exploring. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of reduced battery life and capacity caused by the precipitation of elemental iodine in current acidic and neutral iodine flow batteries by forming iodate and periodate, and to provide an alkaline high-valence iodine flow battery with capacity adjustable with light for large-scale energy storage.

[0005] An alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage comprises a stack consisting of one or more single cells; the single cell includes a positive electrode electrolyte, a negative electrode electrolyte, two light-proof storage tanks, a fixed end plate with a quartz window, a current collector fixed end plate with an S-shaped flow channel, a gasket, an ion sieving membrane, a positive electrode, a negative electrode, and a photocatalytic material;

[0006] The fixed end plate with quartz window and the current collecting fixed end plate with S-shaped flow channel are respectively provided with gaskets on their inner sides, and an ion sieving membrane is provided between the two gaskets; a positive electrode is provided between the fixed end plate with quartz window and the gasket, and a positive electrode chamber is formed between the fixed end plate with quartz window and the ion sieving membrane; a negative electrode is provided between the current collecting fixed end plate with S-shaped flow channel and the gasket, and a negative electrode chamber is formed between the current collecting fixed end plate with S-shaped flow channel and the ion sieving membrane.

[0007] The photocatalytic material is coated on the inner surface of a quartz plate with a fixed end plate and a quartz window, grown in situ on the inner surface of a quartz plate with a fixed end plate and a quartz window, loaded on the positive electrode surface, grown in situ on the positive electrode surface, or added to the positive electrode electrolyte in one or more combinations.

[0008] Two light-shielded storage tanks are installed outside the fixed end plate with a quartz window and the current collector fixed end plate with an S-shaped flow channel. Each light-shielded storage tank is equipped with an inlet pipe, an outlet pipe, and a peristaltic pump. The positive and negative electrolytes are placed in the two light-shielded storage tanks respectively. The light-shielded storage tank containing the positive electrolyte is connected to the positive electrode chamber through an inlet pipe, and the positive electrode chamber is connected to the light-shielded storage tank containing the positive electrolyte through an outlet pipe. The light-shielded storage tank containing the negative electrolyte is connected to the inlet of the S-shaped flow channel on the current collector fixed end plate through an inlet pipe, and the outlet of the S-shaped flow channel is connected to the negative electrode chamber. The negative electrode chamber is connected to the light-shielded storage tank containing the negative electrolyte through an outlet pipe. Two peristaltic pumps are installed on the two inlet pipes respectively.

[0009] The principles and advantages of this invention:

[0010] I. In this invention, the negative and positive electrode materials are porous conductive materials to achieve ion transfer in the electrolyte within the flow channel; this invention utilizes the fact that iodine has multiple valence states in aqueous solution, and I... - / IO3 - and IO4 - / IO3 - The characteristic of low redox overpotential in alkaline systems; the positive electrode active material I under non-light conditions. - High coulombic efficiency oxidation with up to six electron transfers can occur to generate IO3. - During the charging process under light, the positive electrode active material I... - Up to eight electrons can be transferred during oxidation to generate IO4. - This invention allows for short-term fluctuations in energy supply without additional changes to the concentration of active substances in the electrolyte or the addition of other energy storage devices. It is particularly suitable for storing green energy sources such as wind, water, tides, and especially solar energy, which have large supply fluctuations.

[0011] II. In alkaline aqueous solution I - / IO3 - and IO4 - / IO3 -The oxidation overpotential is effectively reduced, but the untreated porous graphite / carbon electrode still cannot match it, causing it to compete for electrons with the oxygen evolution reaction during the oxidation of active materials, affecting the coulombic efficiency and charging voltage of this invention; therefore, in order to maximize the capacity and return point efficiency of this flow battery, it is necessary to find a suitable redox catalyst to expand its application range.

[0012] Third, this invention provides a possibility for developing a high-performance alkaline aqueous flow battery system that utilizes the high valence state of iodine for higher capacity energy storage.

[0013] IV. The alkaline high-valence iodine flow battery provided by this invention has an adjustable capacity based on light intensity for large-scale energy storage. It is suitable for long-term large-scale energy storage. This flow battery is compatible with multiple charge and discharge modes and can be quickly adjusted according to the energy fluctuations that need to be stored. The capacity of this flow battery system is extremely flexible, which can better cope with the fluctuations in the supply of clean energy such as light, and can be applied to long-term large-scale energy storage. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the alkaline high-valence iodine flow battery with adjustable capacity according to light, which is used for large-scale energy storage as described in Example 1, after removing the positive electrode electrolyte, negative electrode electrolyte, two light-proof storage tanks and photocatalytic material. In the figure, 1 is a fixed end plate with a quartz window, 2 is a current collector fixed end plate with an S-shaped flow channel, 3 is a gasket, 4 is an ion sieving membrane, 5 is the negative electrode, 6 is the positive electrode, and 7 is the quartz window.

[0015] Figure 2 This is a schematic diagram of the current collector fixed end plate with an S-shaped flow channel. In the figure, 8 is the liquid inlet of the S-shaped flow channel and 9 is the liquid outlet of the S-shaped flow channel.

[0016] Figure 3 This is a graph showing the change in capacity-voltage over time during charge-discharge cycles of the alkaline high-valence iodine flow battery described in Example 1, which has a capacity adjustable with light intensity for large-scale energy storage, under non-light conditions.

[0017] Figure 4 The graph shows the coulombic efficiency and charge / discharge capacity of the alkaline high-valence iodine flow battery with adjustable capacity under non-light conditions, which is used for large-scale energy storage as described in Example 1. In the graph, 1 is the coulombic efficiency of the battery under non-light conditions and 2 is the charge / discharge capacity.

[0018] Figure 5 For AM 1.5G filter, 100mW / cm 2The charge / discharge capacitance-voltage diagrams of the alkaline high-valence iodine flow battery with adjustable capacity for large-scale energy storage described in Example 1 under both sunlight and non-sunlight conditions are shown. In the diagram, 1 represents the capacitance at 100 mW / cm² under an AM 1.5G filter. 2 1 represents sunlight exposure, and 2 represents non-sunlight exposure;

[0019] Figure 6 This is a schematic diagram of the redox activity of the alkaline high-valence iodine flow battery described in Example 1, whose capacity can be adjusted with light intensity for large-scale energy storage. Detailed Implementation

[0020] Specific Implementation Method 1: This implementation method describes an alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage. It includes a stack consisting of one or more single cells. The single cell includes a positive electrolyte, a negative electrolyte, two light-proof storage tanks, a fixed end plate with a quartz window, a current collector fixed end plate with an S-shaped flow channel, a gasket, an ion sieving membrane, a positive electrode, a negative electrode, and a photocatalytic material.

[0021] The fixed end plate with quartz window and the current collecting fixed end plate with S-shaped flow channel are respectively provided with gaskets on their inner sides, and an ion sieving membrane is provided between the two gaskets; a positive electrode is provided between the fixed end plate with quartz window and the gasket, and a positive electrode chamber is formed between the fixed end plate with quartz window and the ion sieving membrane; a negative electrode is provided between the current collecting fixed end plate with S-shaped flow channel and the gasket, and a negative electrode chamber is formed between the current collecting fixed end plate with S-shaped flow channel and the ion sieving membrane.

[0022] The photocatalytic material is coated on the inner surface of a quartz plate with a fixed end plate and a quartz window, grown in situ on the inner surface of a quartz plate with a fixed end plate and a quartz window, loaded on the positive electrode surface, grown in situ on the positive electrode surface, or added to the positive electrode electrolyte in one or more combinations.

[0023] Two light-shielded storage tanks are installed outside the fixed end plate with a quartz window and the current collector fixed end plate with an S-shaped flow channel. Each light-shielded storage tank is equipped with an inlet pipe, an outlet pipe, and a peristaltic pump. The positive and negative electrolytes are placed in the two light-shielded storage tanks respectively. The light-shielded storage tank containing the positive electrolyte is connected to the positive electrode chamber through an inlet pipe, and the positive electrode chamber is connected to the light-shielded storage tank containing the positive electrolyte through an outlet pipe. The light-shielded storage tank containing the negative electrolyte is connected to the inlet of the S-shaped flow channel on the current collector fixed end plate through an inlet pipe, and the outlet of the S-shaped flow channel is connected to the negative electrode chamber. The negative electrode chamber is connected to the light-shielded storage tank containing the negative electrolyte through an outlet pipe. Two peristaltic pumps are installed on the two inlet pipes respectively.

[0024] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the ion sieving membrane is a perfluorosulfonic acid membrane or a polymer membrane with inherent micropores; the gasket is a fluorinated rubber gasket; and the inlet and outlet pipes are made of acid and alkali resistant Teflon pipes. Other steps are the same as in Specific Implementation Method One.

[0025] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that: the positive electrode is a carbon felt, graphite felt, boron-doped diamond thin film foam electrode, lead dioxide-supported graphite felt, titanium suboxide foam electrode, or iridium-ruthenium titanium oxide composite foam electrode; the negative electrode is a carbon felt, graphite felt, or zinc foam electrode. Other steps are the same as in Specific Implementation Method One or Two.

[0026] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that the negative electrode electrolyte is prepared from a zinc salt, a pH-adjusting electrolyte, a supporting electrolyte, water, and an antifreeze organic solvent. The zinc salt is one or more of zinc sulfate, zinc iodide, zinc bromide, zinc chloride, and zinc nitrate, with a concentration of 0.01 mol / L to 0.2 mol / L. The pH-adjusting electrolyte is one or two of NaOH and KOH, with a concentration of 1 mol / L to 4 mol / L. The supporting electrolyte is one or two of KClO4 and NaClO4, with a concentration of 0 mol / L to 1 mol / L. The antifreeze organic solvent is one or a mixture of several of methanol, anhydrous ethanol, n-propanol, isopropanol, methyl formate, methyl acetate, acetonitrile, benzyl nitrile, dioxonane, diethyl sulfide, sulfolane, sulfonyl lactone, and sulfonyl lactone derivatives. The volume ratio of the antifreeze organic solvent to water is (0–0.3):1. Other steps are the same as in Specific Implementation Methods One to Three.

[0027] Specific Implementation Method Five: This implementation method differs from Specific Implementation Methods One to Four in that the positive electrode electrolyte is prepared from iodized salt, pH-adjusting electrolyte, supporting electrolyte, water, and antifreeze organic solvent. The iodized salt is one or more of KI, NaI, and ZnI2, with a concentration of 0.01 mol / L to 3 mol / L. The pH-adjusting electrolyte is one or two of NaOH and KOH, with a concentration of 1 mol / L to 4 mol / L. The supporting electrolyte is one or two of KClO4 and NaClO4, with a concentration of 0 mol / L to 1 mol / L. The antifreeze organic solvent is one or a mixture of methanol, anhydrous ethanol, n-propanol, isopropanol, methyl formate, methyl acetate, acetonitrile, benzyl nitrile, dioxonane, diethyl sulfide, sulfolane, sulfonyl lactone, and sulfonyl lactone derivatives. The volume ratio of the antifreeze organic solvent to water is (0–0.3):1. Other steps are the same as in Specific Implementation Methods One to Four.

[0028] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that the photocatalytic material is one or more of the following: nano-titanium dioxide, tungsten trioxide, bismuth vanadate, carbon nitride, bismuth tungstate, molybdenum disulfide, zinc oxide, zinc sulfide, bismuth molybdate, bismuth tungstate, bismuth halide, and strontium titanate. The chemical formula of the bismuth halide is BiOX, where X is Cl, Br, or I. The other steps are the same as in Specific Implementation Methods One to Five.

[0029] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One through Six in that: the photocatalytic material is coated on the inner surface of the quartz plate with a fixed end plate and a quartz window, and the ratio of the amount of photocatalytic material to the effective area under light is 0–0.2 g / cm². 2 The coating method is as follows: the photocatalytic material and the binder are mixed at a mass ratio of (0.1-10):1 and then coated onto the inner surface of the quartz plate with the fixed end plate and the quartz window; the binder is polyvinylpyrrolidone, vinyl alcohol, polyethylene glycol, polyacrylamide, polyurethane, polystyrene, or epoxy resin. Other steps are the same as in specific embodiments one to six.

[0030] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: the photocatalytic material is loaded onto the surface of the positive electrode, and the mass ratio of the photocatalytic material to the electrode material is 0-1 g / g; the coating method is as follows: the photocatalytic material and the binder are mixed at a mass ratio of (0.1-10):1 and then loaded onto the surface of the positive electrode. The binder is polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyurethane, polystyrene, or epoxy resin. Other steps are the same as in Specific Implementation Methods One to Seven.

[0031] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that the photocatalytic material is added to the positive electrode electrolyte, and its dosage to electrolyte volume ratio is 0-0.5 g / mL. Other steps are the same as in Specific Implementation Methods One to Eight.

[0032] Specific Implementation Method Ten: The difference between this implementation method and Specific Implementation Methods One to Nine is that: the alkaline high-valence iodine flow battery with adjustable capacity according to light intensity, used for large-scale energy storage, exhibits the following characteristics during charging: The positive electrode active material I... - In solutions with pH > 12, up to 6 electrons are transferred during oxidation to produce I₂ and IO₂. - and IO3 - Negative electrode active material Zn(OH)4 2- In solutions with pH > 12, a two-electron transfer reduction reaction occurs to generate Zn; during discharge, the positive electrode IO3... - A reduction reaction occurs to produce I. - At the negative electrode, Zn undergoes an oxidation reaction to produce Zn(OH)4. 2-Under light conditions, during charging, the positive electrode active material in a solution with pH > 12... - An 8-electron transfer oxidation reaction occurs to produce IO4. - Negative electrode active material Zn(OH)4 2- In solutions with pH > 12, a two-electron transfer reduction reaction occurs to generate Zn; during discharge, the positive electrode contains IO4. - A reduction reaction occurs to produce I. - At the negative electrode, Zn undergoes an oxidation reaction to produce Zn(OH)4. 2- The other steps are the same as those in Specific Implementation Methods One through Nine.

[0033] The beneficial effects of the present invention are verified using the following embodiments:

[0034] Example 1: An alkaline high-valence iodine flow battery with adjustable capacity according to light for large-scale energy storage, comprising a single cell; the single cell includes a positive electrode electrolyte, a negative electrode electrolyte, two light-proof storage tanks, a fixed end plate with a quartz window, a current collector fixed end plate with an S-shaped flow channel, a gasket, an ion sieving membrane, a positive electrode, a negative electrode, and a photocatalytic material;

[0035] The fixed end plate with quartz window and the current collecting fixed end plate with S-shaped flow channel are respectively provided with gaskets on their inner sides, and an ion sieving membrane is provided between the two gaskets; a positive electrode is provided between the fixed end plate with quartz window and the gasket, and a positive electrode chamber is formed between the fixed end plate with quartz window and the ion sieving membrane; a negative electrode is provided between the current collecting fixed end plate with S-shaped flow channel and the gasket, and a negative electrode chamber is formed between the current collecting fixed end plate with S-shaped flow channel and the ion sieving membrane.

[0036] The photocatalytic material is a mixture of 0.04g bismuth vanadate, 0.06g tungsten trioxide, and 0.03g polyvinylpyrrolidone, coated onto the inner surface of a 2*2cm fixed end plate with a quartz window.

[0037] Two light-shielded storage tanks are installed outside the fixed end plate with a quartz window and the current collector fixed end plate with an S-shaped flow channel. Each light-shielded storage tank is equipped with an inlet pipe, an outlet pipe, and a peristaltic pump. The positive electrode electrolyte and the negative electrode electrolyte are placed in the two light-shielded storage tanks respectively. The light-shielded storage tank containing the positive electrode electrolyte is connected to the positive electrode chamber through an inlet pipe, and the positive electrode chamber is connected to the light-shielded storage tank containing the positive electrode electrolyte through an outlet pipe. The light-shielded storage tank containing the negative electrode electrolyte is connected to the inlet of the S-shaped flow channel on the current collector fixed end plate through an inlet pipe, and the outlet of the S-shaped flow channel is connected to the negative electrode chamber. The negative electrode chamber is connected to the light-shielded storage tank containing the negative electrode electrolyte through an outlet pipe. Two peristaltic pumps are installed on the two inlet pipes respectively.

[0038] The ion sieving membrane is Nafion 212; the gasket is a fluorinated rubber gasket; the inlet and outlet pipes are made of acid and alkali resistant Teflon pipes.

[0039] The negative electrode material is selected as a zinc foam electrode;

[0040] The positive electrode material is selected as graphite felt electrode;

[0041] The positive and negative electrode electrolytes are prepared from iodate, pH-adjusting electrolyte, supporting electrolyte, water, and antifreeze organic solvent;

[0042] The negative electrode electrolyte is prepared by mixing 1 mL of anhydrous ethanol and 20 mL of water, then adding zinc sulfate and sodium hydroxide, stirring to dissolve, and obtaining the negative electrode electrolyte; the concentration of zinc sulfate in the negative electrode electrolyte is 100 mmol / L, and the concentration of sodium hydroxide is 3 mol / L.

[0043] The positive electrode electrolyte is prepared by mixing 250 μL of anhydrous ethanol and 5 mL of water, then adding potassium iodide and sodium hydroxide, stirring and dissolving to obtain the positive electrode electrolyte; the concentration of potassium iodide in the positive electrode electrolyte is 50 mmol / L, and the concentration of sodium hydroxide is 3 mol / L.

[0044] The flow rate of the inlet and outlet of the S-shaped flow channel on the current collector fixed end plate is 10 mL / min.

[0045] Figure 1 This is a schematic diagram of the structure of the alkaline high-valence iodine flow battery with adjustable capacity according to light, which is used for large-scale energy storage as described in Example 1, after removing the positive electrode electrolyte, negative electrode electrolyte, two light-proof storage tanks and photocatalytic material. In the figure, 1 is a fixed end plate with a quartz window, 2 is a current collector fixed end plate with an S-shaped flow channel, 3 is a gasket, 4 is an ion sieving membrane, 5 is the negative electrode, 6 is the positive electrode, and 7 is the quartz window.

[0046] Figure 2 This is a schematic diagram of the current collector fixed end plate with an S-shaped flow channel. In the figure, 8 is the liquid inlet of the S-shaped flow channel and 9 is the liquid outlet of the S-shaped flow channel.

[0047] Example 1 describes an alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage. The charge / discharge conditions are selected based on a current density of 10 mA / cm². 2 Perform charging and discharging:

[0048] Under conditions without sunlight exposure, this flow battery system underwent 82 charge-discharge cycles, totaling 240 hours, with charging voltages ranging from 1.9 to 2.4 V and discharging voltages from 0.15 to 0.3 V. During the first 45 charge-discharge cycles, the battery system maintained 100% coulombic efficiency for 6-electron iodide ion charging and discharging. In the subsequent 40 cycles, the battery capacity gradually decreased to the capacity corresponding to 4.5-5 electron iodide ion charging and discharging, but the coulombic efficiency remained at 92% or higher. (See...) Figure 3 and Figure 4 As shown.

[0049] Under the same cyclic conditions, turn on the solar light source equipped with an AM 1.5 filter and adjust it to the corresponding 100mW / cm. 2 When the energy density is perpendicularly irradiated through the quartz window on the battery, the charging voltage decreases from 2-2.4V to 1.8-2.2V, while the discharging voltage increases from 0.2V to 0.5V. Simultaneously, the battery capacity increases from a maximum of six electrons per iodine ion to eight electrons, resulting in a significant improvement in battery performance. (See...) Figure 5 As shown.

[0050] Figure 6 This is a schematic diagram of the redox activity of the alkaline high-valence iodine flow battery described in Example 1, whose capacity can be adjusted with light intensity for large-scale energy storage.

[0051] In summary, this invention discloses an alkaline high-valence iodine electrolyte flow battery. Firstly, this invention utilizes iodine, an abundant and readily available element from the ocean in its oxidized state, as an electrolyte. Its IO4⁻… - / IO3 - Potential formed by two-electron transfer (< -0.7V vs. SHE) and IO3 - / I - The potential formed by the six-electron transfer (<-0.4V vs. SHE) is excellent, matching the potential of electrodeposited solid Zn in alkaline solvents (<-1.2V vs. SHE). The porous electrode in the flow battery offers the advantage of a larger reaction area, reducing overpotential and resulting in higher battery efficiency. Secondly, the energy of this invention is stored in the electrolyte, and the stored energy can be altered by changing the electrolyte volume or adjusting the valence state of iodine, providing energy storage scalability not found in traditional metal batteries. Furthermore, since the electrolyte is centrally stored in an electrolyte tank, regular maintenance or replacement is convenient, and rapid charging can be achieved by directly replacing the electrolyte. Compared to traditional flow batteries, this invention is more suitable for storing energy sources with large fluctuations in energy supply, such as wind, tides, and solar energy.

Claims

1. An alkaline high-valence iodine flow battery with adjustable capacity based on light intensity for large-scale energy storage, characterized in that... It includes a stack consisting of one or more single cells; the single cell includes a positive electrolyte, a negative electrolyte, two light-proof storage tanks, a fixed end plate with a quartz window, a current collecting fixed end plate with an S-shaped flow channel, a gasket, an ion sieving membrane, a positive electrode, a negative electrode, and a photocatalytic material. The fixed end plate with quartz window and the current collecting fixed end plate with S-shaped flow channel are respectively provided with gaskets on their inner sides, and an ion sieving membrane is provided between the two gaskets; a positive electrode is provided between the fixed end plate with quartz window and the gasket, and a positive electrode chamber is formed between the fixed end plate with quartz window and the ion sieving membrane; a negative electrode is provided between the current collecting fixed end plate with S-shaped flow channel and the gasket, and a negative electrode chamber is formed between the current collecting fixed end plate with S-shaped flow channel and the ion sieving membrane. The photocatalytic material is coated on the inner surface of a quartz plate with a fixed end plate and a quartz window, grown in situ on the inner surface of a quartz plate with a fixed end plate and a quartz window, loaded on the positive electrode surface, or added to the positive electrode electrolyte in one or more combinations. Two light-shielded storage tanks are installed outside the fixed end plate with a quartz window and the current collector fixed end plate with an S-shaped flow channel. Each light-shielded storage tank is equipped with an inlet pipe, an outlet pipe, and a peristaltic pump. The positive electrode electrolyte and the negative electrode electrolyte are placed in the two light-shielded storage tanks respectively. The light-shielded storage tank containing the positive electrode electrolyte is connected to the positive electrode chamber through an inlet pipe, and the positive electrode chamber is connected to the light-shielded storage tank containing the positive electrode electrolyte through an outlet pipe. The light-shielded storage tank containing the negative electrode electrolyte is connected to the inlet of the S-shaped flow channel on the current collector fixed end plate through an inlet pipe, and the outlet of the S-shaped flow channel is connected to the negative electrode chamber. The negative electrode chamber is connected to the light-shielded storage tank containing the negative electrode electrolyte through an outlet pipe. Two peristaltic pumps are installed on the two inlet pipes respectively. The negative electrode electrolyte includes a zinc salt and a pH-adjusting electrolyte, wherein the zinc salt is one or more of zinc sulfate, zinc iodide, zinc bromide, zinc chloride or zinc nitrate, and the pH-adjusting electrolyte is one or two of NaOH or KOH. The positive electrode electrolyte includes iodized salt and pH-adjusting electrolyte, wherein the iodized salt is one or more of KI, NaI or ZnI2, and the pH-adjusting electrolyte is one or two of NaOH or KOH. The photocatalytic material is one or more of the following: nano-titanium dioxide, tungsten trioxide, bismuth vanadate, carbon nitride, bismuth tungstate, molybdenum disulfide, zinc oxide, zinc sulfide, bismuth molybdate, bismuth tungstate, bismuth oxyhalide, or strontium titanate, wherein the chemical formula of bismuth oxyhalide is BiOX, and X is Cl, Br, or I.

2. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The ion sieving membrane is a perfluorosulfonic acid membrane or a polymer membrane with inherent micropores; the gasket is a fluorinated rubber gasket; and the inlet and outlet pipes are made of acid and alkali resistant Teflon pipes.

3. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The positive electrode is a carbon felt, graphite felt, boron-doped diamond thin film foam electrode, lead dioxide-supported graphite felt, titanium suboxide foam electrode, or iridium-ruthenium titanium oxide composite foam electrode; the negative electrode is a carbon felt, graphite felt, or zinc foam electrode.

4. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The negative electrode electrolyte is prepared from zinc salt, pH-adjusting electrolyte, supporting electrolyte, water, and antifreeze organic solvent. The concentration of zinc salt is 0.01 mol / L to 0.2 mol / L, the concentration of pH-adjusting electrolyte is 1 mol / L to 4 mol / L, the supporting electrolyte is one or both of KClO4 and NaClO4 with a concentration of less than or equal to 1 mol / L, and the antifreeze organic solvent is one or a mixture of methanol, anhydrous ethanol, n-propanol, isopropanol, methyl formate, methyl acetate, acetonitrile, benzyl nitrile, dioxonane, diethyl sulfide, sulfolane, sulfonyl lactone, or sulfonyl lactone derivatives. The volume ratio of the antifreeze organic solvent to water is less than or equal to 0.3:

1.

5. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The positive electrode electrolyte is prepared from iodized salt, pH-adjusting electrolyte, supporting electrolyte, water, and antifreeze organic solvent. The concentration of iodized salt is 0.01 mol / L to 3 mol / L, the concentration of pH-adjusting electrolyte is 1 mol / L to 4 mol / L, the supporting electrolyte is one or both of KClO4 and NaClO4, and its concentration is less than or equal to 1 mol / L. The antifreeze organic solvent is one or a mixture of several of methanol, anhydrous ethanol, n-propanol, isopropanol, methyl formate, methyl acetate, acetonitrile, benzyl nitrile, dioxonane, diethyl sulfide, sulfolane, sulfonyl lactone, or sulfonyl lactone derivatives. The volume ratio of the antifreeze organic solvent to water is less than or equal to 0.3:

1.

6. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The photocatalytic material is coated on the inner surface of a quartz plate with a fixed end plate and a quartz window. The ratio of the amount of photocatalytic material to the effective area under light illumination is less than or equal to 0.2 g / cm². 2 The coating method is as follows: the photocatalytic material and the binder are mixed at a mass ratio of (0.1~10):1 and then coated on the inner surface of the quartz plate with the fixed end plate of the quartz window; the binder is polyvinylpyrrolidone, vinyl alcohol, polyethylene glycol, polyacrylamide, polyurethane, polystyrene or epoxy resin.

7. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The photocatalytic material is loaded onto the surface of the positive electrode, and the mass ratio of the photocatalytic material to the electrode material is less than or equal to 1 g / g. The loading method is as follows: the photocatalytic material and the binder are mixed at a mass ratio of (0.1~10):1 and then loaded onto the surface of the positive electrode. The binder is polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyurethane, polystyrene or epoxy resin.

8. The alkaline high-valence iodine flow battery with capacity adjustable with light intensity for large-scale energy storage as described in claim 1, characterized in that... The photocatalytic material is added to the positive electrode electrolyte, and its dosage is less than or equal to 0.5 g / mL compared with the volume of the electrolyte.

9. The alkaline high-valence iodine flow battery with adjustable capacity according to light intensity for large-scale energy storage as described in claim 1, characterized in that... The alkaline high-valence iodine flow battery described above, which has a capacity adjustable with light intensity for large-scale energy storage, exhibits high efficiency during charging of the positive electrode active material I under conditions of no light. - In solutions with pH > 12, up to 6 electrons are transferred during oxidation to produce I₂ and IO₂. - and IO3 - Negative electrode active material Zn(OH)4 2- In solutions with pH > 12, a two-electron transfer reduction reaction occurs to generate Zn; during discharge, the positive electrode IO3... - A reduction reaction occurs to produce I. - At the negative electrode, Zn undergoes an oxidation reaction to produce Zn(OH)4. 2- Under light conditions, during charging, the positive electrode active material in a solution with pH > 12... - An 8-electron transfer oxidation reaction occurs to produce IO4. - Negative electrode active material Zn(OH)4 2- In solutions with pH > 12, a two-electron transfer reduction reaction occurs to generate Zn; during discharge, the positive electrode contains IO4. - A reduction reaction occurs to produce I. - At the negative electrode, Zn undergoes an oxidation reaction to produce Zn(OH)4. 2- .

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