High-rate aqueous flow battery based on natural salt cavern and preparation method of high-rate aqueous flow battery

Abstract

The invention discloses a high-magnification aqueous flow battery based on a natural salt cavern and a preparation method of the high-magnification aqueous flow battery, and belongs to the technical field of flow batteries. The flow battery takes a natural salt-cavern solution as a basic supporting electrolyte, and the salt-cavern solution is naturally rich in sodium chloride and contains a small amount of mineral substances such as magnesium sulfate; on the basis, one or more inorganic ions and organic active molecules with redox reversibility are further introduced, so that a composite electrolyte system with excellent rate capability and electrochemical stability is constructed. The salt cavern solution has a saturation characteristic and relatively low temperature sensitivity, the ionic strength and conductivity of the electrolyte are remarkably improved by combining with the addition of inorganic ions, and the electrode reaction kinetics is enhanced, so that the flow battery still has good performance under high-rate charging and discharging. The high-rate aqueous flow battery based on the natural salt cavern, provided by the invention, has the characteristics of excellent rate capability, stable cycle performance and the like, and has a wide application prospect in long-time energy storage and rapid charging and discharging scenes.

Description

Technical Field

[0001] The present invention belongs to the technical field of aqueous liquid flow battery electrolytes and relates to a high-rate aqueous liquid flow battery based on natural salt caverns and a preparation method thereof. Background Art

[0002] Salt caves are huge caves formed underground after salt mines are mined by water solution. Their shape and volume vary depending on geological conditions. Usually the volume can reach 10 7 ~10 8 cubic meters. Due to their stable structure, good sealing, and excellent safety, salt caverns are often used to store substances insoluble in brine. In recent years, the inorganic ion resources rich in salt caverns have gradually been applied to energy storage technology, especially in salt cavern flow battery systems, showing potential for application.

[0003] When the salt cave flow battery system is in operation, the positive and negative electrolytes are driven by circulating pumps and circulate between the salt cavern storage tank and the two half-cell chambers, respectively. The efficient conversion between chemical energy and electrical energy is achieved through the reversible redox reactions of the redox-active substances in the electrolyte at the positive and negative electrodes. The energy of the salt cave flow battery is stored in the electrolyte outside the electrodes, rather than in the electrodes themselves, so the composition of the electrolyte plays a decisive role in the battery's performance. However, current salt cave flow batteries generally use unadjusted natural salt cave solutions as electrolytes. In practical applications, they still face problems such as poor rate performance and low energy conversion efficiency, resulting in slow battery charge and discharge rates and insufficient dynamic response capabilities, which restricts their promotion and application in high-power energy storage scenarios. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems of poor rate performance and low energy conversion efficiency when salt cavern solutions are directly used as electrolytes in liquid flow batteries in the prior art, and to provide a high-rate aqueous liquid flow battery based on natural salt caverns and a preparation method thereof, so as to achieve higher charge and discharge rates, better cycle performance and stronger environmental adaptability.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A high-rate aqueous flow battery based on a natural salt cavern, comprising a positive electrode electrolyte, a battery stack, and a negative electrode electrolyte. The positive electrode electrolyte is stored in a positive electrode storage tank, and the negative electrode electrolyte is stored in a negative electrode storage tank. Both the positive electrode storage tank and the negative electrode storage tank are connected to the battery stack, and an ion exchange membrane is provided in the battery stack.

[0007] The positive electrode electrolyte includes a supporting electrolyte, a positive electrode organic redox active substance and inorganic ions;

[0008] The negative electrode electrolyte includes a supporting electrolyte, a negative electrode organic redox active material and inorganic ions;

[0009] The supporting electrolytes in the positive electrode electrolyte and the negative electrode electrolyte are both salt cave solutions, and the inorganic ions are any one or more combinations of monovalent ions and their hydrates, divalent ions and their hydrates, or trivalent ions and their hydrates.

[0010] A further improvement of the present invention is:

[0011] Preferably, the positive electrode organic redox active substance is any one of a cyclic nitroxide free radical derivative and a ferrocene derivative.

[0012] Preferably, the negative electrode redox active material is any one of 4,4'-bipyridyl salt derivatives, imide derivatives, oxazine derivatives and quinone derivatives.

[0013] Preferably, the monovalent ion is any one or more of potassium ion and its hydrate, ammonium ion and its hydrate or lithium ion and its hydrate.

[0014] Preferably, the divalent ion is any one or more of magnesium ion and its hydrate, calcium ion and its hydrate, zinc ion and its hydrate or barium ion and its hydrate.

[0015] Preferably, the trivalent ion is any one or more of aluminum ion and its hydrate, iron ion and its hydrate or chromium ion and its hydrate.

[0016] Preferably, the concentration of the inorganic ions in the positive electrode electrolyte is 0.05 to 2.50M.

[0017] Preferably, the concentration of the positive electrode organic redox active material is 0.05-2.50M.

[0018] Preferably, the concentration of the negative electrode organic redox active material is 0.05-2.50M.

[0019] A method for preparing a high-rate aqueous flow battery based on a natural salt cave solution comprises the following steps:

[0020] S1, using the salt cave solution as the supporting electrolyte according to the set concentration and composition, adding inorganic ions thereto, and adding the positive electrode organic redox active material and the negative electrode organic redox active material respectively to obtain the positive electrode electrolyte and the negative electrode electrolyte;

[0021] S2, placing the positive electrode electrolyte in the positive electrode storage tank, placing the negative electrode electrolyte in the negative electrode storage tank, assembling the positive electrode storage tank, the battery stack and the negative electrode storage tank to form an aqueous liquid flow battery.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The present invention discloses a high-rate electrolyte and aqueous flow battery based on natural salt caverns, including a supporting electrolyte based on a naturally occurring salt cavern solution, one or more added inorganic ions, and an organic electrolyte molecule with redox activity. Since the salt cavern solution is rich in sodium chloride and a small amount of magnesium sulfate as a supporting electrolyte, and the added inorganic ions effectively increase the ion concentration in the electrolyte, it has properties such as very high electronic and ionic conductivity, which can support the high-rate rapid charge and discharge process of the battery and improve the battery rate performance; in addition, the introduced inorganic ions can form complexes or ion pairs with the active organic electrolyte molecules, inhibiting their aggregation and precipitation, so that the active substances can be evenly dispersed in the solution, and the redox reaction is more stable; at the same time, there is no side reaction when ions are added to the salt cavern solution, so the supporting electrolyte enables the electrolyte to maintain good electron storage and release stability. The excellent conductivity and electrochemical stability of the high-rate electrolyte provided by the present invention make it have broad application prospects. The flow battery of the present invention also has the following advantages:

[0024] (1) High-rate charge-discharge performance: Natural salt cavern solutions are rich in sodium chloride and contain a small amount of magnesium sulfate, which provides a natural raw material basis for constructing high-rate electrolytes. At the same time, the present invention introduces inorganic ions to further optimize the composition of the natural salt cavern solution, achieving high ion concentration and high conductivity in the electrolyte, thereby significantly improving the battery's charge-discharge rate. This high-rate performance enables the battery to charge and discharge rapidly in a short period of time, meeting the demand for fast-response energy storage.

[0025] (2) Enhanced cycle life: Inorganic ions can form complexes or ion pairs with active organic electrolyte molecules to inhibit their aggregation and precipitation; the supporting electrolyte concentration is constant, and the electrolyte can maintain good electron storage and release stability during its application, so that the battery exhibits excellent cycle durability in long-term cyclic use. This not only reduces the maintenance cost and replacement frequency of the battery, but also improves the economy and reliability of the entire energy storage system.

[0026] (3) Environmental friendliness: The electrolyte of the present invention is based on natural salt cavern solutions. The active substances are composed of elements such as C, H, O, and N, and the introduced inorganic ions are also environmentally friendly. In addition, the high efficiency and long life of the battery also reduce energy consumption, showing the potential for sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a comparative example of an aqueous flow battery without ion addition. Figure 2 In Example 1, the aqueous flow battery with a concentration of 0.05M magnesium chloride and its hydrate was tested at a current density of 20-90 mA·cm -2 , current density interval 5mA·cm -2, 5 cycles at each current density, the battery discharge capacity, coulombic efficiency, and energy efficiency change curves with the number of cycles.

[0028] Figure 3 Example 2 is represented, wherein (a) is a curve showing the change of battery discharge capacity, coulombic efficiency, and energy efficiency with the number of cycles during a long cycle of an aqueous liquid flow battery with an added concentration of 0.05M magnesium chloride and its hydrate and an electrolyte concentration of 0.05M, and (b) is the capacity-voltage curve of the battery at the 1st, 50th, and 80th cycles.

[0029] Figure 4 The graph shows the variation of battery discharge capacity, coulombic efficiency and energy efficiency with the number of cycles in the aqueous flow battery with an electrolyte concentration of 0.25 M during a long cycle in Example 3.

[0030] Figure 5 The graph shows the variation of battery discharge capacity, coulombic efficiency and energy efficiency with the number of cycles in the aqueous flow battery with an electrolyte concentration of 1.50 M during a long cycle in Example 4. DETAILED DESCRIPTION

[0031] The present invention is described in further detail below with reference to the accompanying drawings:

[0032] To facilitate understanding of the features and effects of the present invention by those skilled in the art, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings as understood by those skilled in the art regarding the present invention. In the event of conflict, the definitions in this specification shall prevail.

[0033] In this document, unless otherwise specified, “include,” “including,” “contains,” “has” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0034] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

[0035] The following examples were prepared using conventional instruments and equipment in the art. Experimental methods in the following examples, where specific conditions are not specified, were generally performed under conventional conditions or according to the conditions recommended by the manufacturer. The various raw materials used in the following examples, unless otherwise specified, were conventional commercially available products, with specifications conventional in the art. In the present specification and the following examples, unless otherwise specified, "%" indicates percentage by weight, "part" indicates parts by weight, and "ratio" indicates weight ratio.

[0036] The present invention discloses a high-rate aqueous liquid flow battery based on a natural salt cavern. The aqueous liquid flow battery comprises a positive electrode electrolyte, a battery stack and a negative electrode electrolyte. The positive electrode electrolyte is in a positive electrode storage tank, and the negative electrode electrolyte is in a negative electrode storage tank. Both the positive electrode storage tank and the negative electrode storage tank are connected to the battery stack, and a diaphragm is provided in the battery stack.

[0037] The positive electrode includes a supporting electrolyte, a positive electrode redox active substance and inorganic ions; the negative electrode includes a supporting electrolyte, a negative electrode redox active substance and inorganic ions.

[0038] The supporting electrolytes in the positive electrode and the negative electrode are both salt cave solutions; and the inorganic ions are any one or more combinations of monovalent ions, divalent ions or trivalent ions.

[0039] The present invention adds inorganic ions to an aqueous liquid flow battery using a salt cavern solution as a supporting electrolyte, which can make the electrolyte have higher electronic and ionic conductivities and improve the redox reaction stability of active organic electrolyte molecules.

[0040] In some embodiments of the present invention, the positive electrode redox active material is trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl radical chloride (TMA-TEMPO), and the concentration of the positive electrode redox active material is 0.05-2.50M.

[0041] The negative electrode redox active substance is 1,1-dimethyl-4,4'-bipyridinium dichloride, and the concentration of the negative electrode redox active substance is 0.05-2.50M.

[0042] Exemplary 4,4'-bipyridinium derivatives can be 1,1-dimethyl-4,4'-bipyridinium dichloride (MV), 1,1-diethyl-4,4'-bipyridinium dichloride (EV), 1,1-diisopropyl-4,4'-bipyridinium dichloride (iPrV), bis(3-sulfonylpropyl)-2,2',6,6'-tetramethyl-4,4'-bipyridinium (R-Vi), bis(3-sulfonylpropyl)-4,4'-bipyridinium (S-Vi), and bis(3-trimethylammonio)propyl-4,4 '-bipyridinium tetrachloride (BTMAP-Vi), etc. The cyclic nitrogen oxide free radical derivatives can be trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride (4-TMA-TEMPO), 4-hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl free radical (4-OH-TEMPO), 2,2,6,6-tetramethylpiperidinyloxy-4-carboxylate sodium (4-CO2Na-TEMPO), 2,2,6,6-tetramethylpiperidinyloxy-4-potassium sulfate (4-SO4K-TEMPO), etc.

[0043] The structural formulas of representative redox active substances are shown in the following table.

[0044] Table 1 Representative redox active substances

[0045]

[0046]

[0047] The inorganic ion can be any one or more combinations of monovalent ions and hydrates thereof, divalent ions and hydrates thereof, or trivalent ions and hydrates thereof.

[0048] Furthermore, the monovalent ion is any one or more of potassium ion and its hydrate, ammonium ion and its hydrate or lithium ion and its hydrate; the divalent ion is any one or more of magnesium ion and its hydrate, calcium ion and its hydrate, zinc ion and its hydrate or barium ion and its hydrate; the trivalent ion is any one or more of aluminum ion and its hydrate, iron ion and its hydrate or chromium ion and its hydrate.

[0049] Specifically, the corresponding substances directly added are potassium chloride and its hydrates, ammonium chloride and its hydrates, lithium chloride and its hydrates, magnesium chloride and its hydrates, calcium chloride and its hydrates, zinc chloride and its hydrates, barium chloride and its hydrates, aluminum chloride and its hydrates, and ferric chloride and its hydrates. In the present invention, chloride ions are directly used as anions, which are the same as the main ions in the salt caverns, and can avoid precipitation.

[0050] As a preferred option, the inorganic ions selected are monovalent potassium ions and their hydrates, divalent magnesium ions and their hydrates or calcium ions and their hydrates, trivalent aluminum ions and their hydrates or iron ions and their hydrates, and one or more of them are arbitrarily selected for combination. When multiple inorganic ions are combined, the rate performance is higher and the charging is faster.

[0051] As a preferred solution, the concentration of the introduced inorganic ions in the electrolyte is 0.05 to 2.50M.

[0052] In some exemplary embodiments, only divalent magnesium ions and their hydrates or at least one of the above ions are selected for combination. The magnesium ions can form more stable complexes or ion pairs with the active organic electrolyte molecules, more effectively inhibit their aggregation and precipitation, and provide better rate performance.

[0053] More preferably, the molar ratio of the introduced divalent magnesium ions and their hydrates to the viologen molecules is 1:5 to 1:2.

[0054] The membrane can be an anion exchange membrane.

[0055] The above-mentioned method for assembling an aqueous liquid flow battery with a high-rate electrolyte based on a natural salt cavern comprises the following steps:

[0056] Step 1: Using a salt cave solution as a supporting electrolyte, adding inorganic ions at a fixed concentration, and then adding a positive electrode redox active substance and a negative electrode redox active substance, respectively, to obtain a positive electrode electrolyte and a negative electrode electrolyte;

[0057] Step 2: Place the positive electrode electrolyte in the positive electrode storage tank, place the negative electrode electrolyte in the negative electrode storage tank, assemble the positive electrode storage tank, the battery stack and the negative electrode storage tank to form an aqueous liquid flow battery.

[0058] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described below are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0059] Comparative Example 1

[0060] The positive electrolyte was composed of 0.05 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl chloride dissolved in 8 mL of salt cave solution. The negative electrolyte was composed of 0.05 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8 mL of salt cave solution. The solutions were prepared according to the above formulas and stirred uniformly. Inert gas was introduced into the solutions to remove oxygen.

[0061] The prepared electrolyte was placed in a reservoir. The battery separator used an anion exchange membrane and the electrodes used graphite felt. The positive and negative electrode reservoirs, the stack, and the peristaltic pump were assembled to create an aqueous organic flow battery based on a salt cave solution. The prepared electrolyte was placed in an inert gas-filled glove box for rate performance and long-cycle stability testing. The rate performance test was performed at a current density of 20-90 mA cm -2 , current density interval 5mA·cm -2 5 cycles at each current density, the current density of the long cycle stability test is 40mA·cm -2 The working steps are constant current charge and discharge, the charge cut-off voltage is 1.6V, and the discharge cut-off voltage is 0.9V.

[0062] Example 1

[0063] Magnesium chloride and its hydrate at a concentration of 0.05M were added to the salt cave solution. The positive electrolyte composition was: 0.05M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 8mL of the salt cave solution. The negative electrolyte composition was: 0.05M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0064] The prepared electrolyte was placed in a reservoir. The battery separator used an anion exchange membrane and the electrodes used graphite felt. The positive and negative electrode reservoirs, the stack, and the peristaltic pump were assembled to create an aqueous organic flow battery based on a salt cavern solution. The prepared electrolyte was placed in an inert gas-filled glove box for rate performance testing at a current density of 20-90 mA cm -2 , current density interval 5mA·cm -2 , 5 cycles were performed at each current density, the working steps were constant current charge and discharge, the charging cut-off voltage was 1.6V, and the discharging cut-off voltage was 0.9V.

[0065] Comparative Example 1 Figure 1 and Example 1 Figure 2 The comparison shows that the discharge capacity, coulombic efficiency and energy efficiency of the aqueous flow battery based on salt cave solution at different rates change, and the flow battery with added magnesium ions and their hydrates has excellent rate performance and can discharge at 90mA cm -2 The battery has a capacity utilization rate of 45% at a high current density, compared with a liquid flow battery without added magnesium ions, which has a capacity utilization rate of only 16% at the same current density.

[0066] Example 2

[0067] Magnesium chloride and its hydrate at a concentration of 0.05M were added to the salt cave solution. The positive electrolyte composition was: 0.05M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 8mL of the salt cave solution. The negative electrolyte composition was: 0.05M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0068] The prepared electrolyte was placed in a reservoir. The battery separator used an anion exchange membrane and the electrodes used graphite felt. The positive and negative electrode reservoirs, the stack, and the peristaltic pump were assembled to create an aqueous organic flow battery based on a salt cavern solution. The prepared electrolyte was placed in an inert gas-filled glove box for long-term cycle stability testing at a current density of 40 mA cm. -2 The working steps are constant current charge and discharge, the charge cut-off voltage is 1.6V, and the discharge cut-off voltage is 0.9V.

[0069] Figure 3 (a) shows the change curve of battery discharge capacity, coulombic efficiency, and energy efficiency with the number of cycles in an aqueous flow battery with an electrolyte concentration of 0.05 M and an addition concentration of 0.05 M magnesium chloride and its hydrate. Figure 3 (b) shows the capacity-voltage curves of the battery at the 1st, 50th, and 80th cycles. The battery cycled stably for 80 cycles with a Coulombic efficiency >99% and an energy efficiency ≈80%, demonstrating that the salt cave solution with magnesium ions has excellent long-term cycling stability.

[0070] Example 3

[0071] Magnesium chloride and its hydrate at a concentration of 0.25M were added to the salt cave solution. The positive electrolyte composition was: 0.25M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 10mL of the salt cave solution. The negative electrolyte composition was: 0.05M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 10mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0072] The prepared electrolyte was placed in a reservoir. The battery separator used an anion exchange membrane and the electrodes used graphite felt. The positive and negative electrode reservoirs, the stack, and the peristaltic pump were assembled to create an aqueous organic flow battery based on a salt cavern solution. The prepared electrolyte was placed in an inert gas-filled glove box for long-term cycle stability testing at a current density of 40 mA cm. -2 The working steps are constant current charge and discharge, the charge cut-off voltage is 1.6V, and the discharge cut-off voltage is 0.9V.

[0073] Figure 4 The figure shows the changes in discharge capacity, coulombic efficiency, and energy efficiency over the long-term cycling of an aqueous flow battery with an electrolyte concentration of 0.25M. The battery maintained stable cycling for 260 cycles, with a coulombic efficiency >99% and an energy efficiency ≈80%. This demonstrates that the flow battery constructed using salt cavern solutions containing magnesium ions and their hydrates exhibits excellent long-term cycling stability.

[0074] Example 4

[0075] Magnesium chloride and its hydrate at a concentration of 1.50 M were added to the salt cave solution. The positive electrolyte composition was: 1.50 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 8 mL of the salt cave solution. The negative electrolyte composition was: 1.50 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8 mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0076] The prepared electrolyte was placed in a reservoir. The battery separator used an anion exchange membrane and the electrodes used graphite felt. The positive and negative electrode reservoirs, the stack, and the peristaltic pump were assembled to create an aqueous organic flow battery based on a salt cavern solution. The prepared electrolyte was placed in an inert gas-filled glove box for long-term cycle stability testing at a current density of 40 mA cm. -2 The working steps are constant current charge and discharge, the charge cut-off voltage is 1.6V, and the discharge cut-off voltage is 0.9V.

[0077] Figure 5 The figure shows the variation of discharge capacity, coulombic efficiency, and energy efficiency over the number of cycles for an aqueous flow battery with an electrolyte concentration of 1.50M over a long cycle. The battery cycled stably for over 200 cycles, with a coulombic efficiency >99% and an energy efficiency ≈80%, demonstrating that the flow battery constructed using salt cavern solutions containing magnesium ions and their hydrates exhibits excellent long-term cycling stability.

[0078] Example 5

[0079] Magnesium chloride and its hydrate at a concentration of 0.35M were added to the salt cave solution. The positive electrolyte was composed of 1.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0080] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0081] Example 6

[0082] Magnesium chloride and its hydrate at a concentration of 0.50M were added to the salt cave solution. The positive electrolyte was composed of 1.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0083] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0084] Example 7

[0085] Magnesium chloride and its hydrate at a concentration of 1.00 M were added to the salt cave solution. The positive electrolyte was composed of 1.50 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0086] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0087] Example 8

[0088] Magnesium chloride and its hydrate at a concentration of 2.00 M were added to the salt cave solution. The positive electrolyte was composed of 1.50 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0089] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0090] Example 9

[0091] Potassium chloride and its hydrate at a concentration of 1.50M were added to the salt cave solution. The positive electrolyte was composed of 1.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0092] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0093] Example 10

[0094] Lithium chloride and its hydrate at a concentration of 1.50M were added to the salt cave solution. The positive electrolyte was composed of 1.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0095] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0096] Example 11

[0097] Calcium chloride and its hydrate at a concentration of 1.50M were added to the salt cave solution. The positive electrolyte was composed of 1.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 1.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solutions were prepared according to the above formula and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0098] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0099] Example 12

[0100] Chromium chloride and its hydrate at a concentration of 1.50 M were added to the salt cave solution. The positive electrolyte composition was: 1.50 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 8 mL of the salt cave solution. The negative electrolyte composition was: 1.50 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8 mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0101] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0102] Example 13

[0103] Magnesium chloride and its hydrate at a concentration of 1.50 M were added to the salt cave solution. The positive electrolyte composition was: 1.50 M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in 8 mL of the salt cave solution. The negative electrolyte composition was: 1.50 M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in 8 mL of the salt cave solution. According to the above formula, the solution was prepared and stirred uniformly. Inert gas was introduced into the solution to remove oxygen.

[0104] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0105] Example 14

[0106] Magnesium chloride and its hydrate at a concentration of 0.50M were added to the salt cave solution. The positive electrolyte was composed of 0.50M (ferrocenylmethyl)trimethylammonium chloride dissolved in the salt cave solution. The negative electrolyte was composed of 0.50M 1,1-dimethyl-4,4'-bipyridinium dichloride dissolved in the salt cave solution. The solution was prepared according to the above formula and stirred evenly. Inert gas was introduced into the solution to remove oxygen.

[0107] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0108] Example 15

[0109] Magnesium chloride and its hydrate at a concentration of 0.50M were added to the salt cave solution. The positive electrolyte was composed of 0.50M trimethylammonium-2,2,6,6-tetramethylpiperidin-1-oxyl free radical chloride dissolved in the salt cave solution. The negative electrolyte was composed of 0.50M naphthalene diimide dissolved in the salt cave solution. The solution was prepared according to the above formula and stirred evenly. Inert gas was introduced into the solution to remove oxygen.

[0110] The prepared electrolyte is placed in a storage tank. The battery separator uses an anion exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0111] Example 16

[0112] Magnesium chloride and its hydrate at a concentration of 0.50M were added to the salt cave solution. The positive electrolyte was composed of 0.50M 2,2,6,6-tetramethylpiperidinyloxy-4-potassium sulfate dissolved in the salt cave solution. The negative electrolyte was composed of 0.50M 1,6-dihydroxyphenazine dissolved in the salt cave solution. The solution was prepared according to the above formula and stirred evenly. Inert gas was introduced into the solution to remove oxygen.

[0113] The prepared electrolyte is placed in a storage tank. The battery separator uses a cation exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0114] Example 17

[0115] Magnesium chloride and its hydrate at a concentration of 0.50M were added to the salt cave solution. The positive electrolyte was composed of 0.50M 2,2,6,6-tetramethylpiperidinyloxy-4-potassium sulfate dissolved in the salt cave solution. The negative electrolyte was composed of 0.50M 2,6-dihydroxyanthraquinone dissolved in the salt cave solution. The solution was prepared according to the above formula and stirred evenly. Inert gas was introduced into the solution to remove oxygen.

[0116] The prepared electrolyte is placed in a storage tank. The battery separator uses a cation exchange membrane and the electrodes use graphite felt. After assembling the positive and negative electrode storage tanks, the battery stack, and the peristaltic pump, a salt cave solution-based aqueous organic flow battery is obtained.

[0117] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high-rate aqueous flow battery based on natural salt cavern solution, characterized in that: The battery comprises a positive electrode electrolyte, a battery stack and a negative electrode electrolyte. The positive electrode electrolyte is stored in a positive electrode storage tank, and the negative electrode electrolyte is stored in a negative electrode storage tank. Both the positive electrode storage tank and the negative electrode storage tank are connected to the battery stack, and an ion exchange membrane and electrodes are provided in the battery stack. The positive electrode electrolyte includes a supporting electrolyte, a positive electrode organic redox active substance and inorganic ions; The negative electrode electrolyte includes a supporting electrolyte, a negative electrode organic redox active material and inorganic ions; The supporting electrolytes in the positive electrode electrolyte and the negative electrode electrolyte are both salt cave solutions, and the inorganic ions are any one or more combinations of monovalent ions and their hydrates, divalent ions and their hydrates, or trivalent ions and their hydrates.

2. A high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The positive electrode organic redox active substance is a cyclic nitrogen oxide free radical derivative or a ferrocene derivative.

3. A high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The organic negative electrode redox active material is a 4,4'-bipyridyl salt derivative, an imide derivative, an oxazine derivative and a quinone derivative.

4. A high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The monovalent ion is any one or more of potassium ion and its hydrate, ammonium ion and its hydrate or lithium ion and its hydrate.

5. The high-rate aqueous flow battery based on natural salt caverns according to claim 1, characterized in that: The divalent ions are any one or more of magnesium ions and their hydrates, calcium ions and their hydrates, zinc ions and their hydrates, or barium ions and their hydrates.

6. The high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The trivalent ions are any one or more of aluminum ions and their hydrates, iron ions and their hydrates, and chromium ions and their hydrates.

7. The high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The concentration of the inorganic ions in the positive electrode electrolyte is 0.05 to 2.50M.

8. The high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The concentration of the positive electrode organic redox active material is 0.05-2.50M.

9. The high-rate aqueous flow battery based on a natural salt cavern according to claim 1, characterized in that: The concentration of the negative electrode organic redox active material is 0.05-2.50M.

10. A method for preparing a high-rate aqueous flow battery based on a natural salt cavern, characterized in that: The following steps are involved: S1, using the salt cave solution as the supporting electrolyte according to the set concentration and composition, adding inorganic ions thereto, and then adding the positive electrode organic redox active material and the negative electrode organic redox active material respectively to prepare the positive electrode electrolyte and the negative electrode electrolyte; S2, placing the positive electrode electrolyte in the positive electrode storage tank, placing the negative electrode electrolyte in the negative electrode storage tank, assembling the positive electrode storage tank, the battery stack and the negative electrode storage tank to form an aqueous liquid flow battery.

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