CN109599577B

CN109599577B - Water phase system organic flow battery system based on salt cavern

Info

Publication number: CN109599577B
Application number: CN201811252983.2A
Authority: CN
Inventors: 徐俊辉; 韩俊甜; 崔耀星; 苏志俊; 李丹; 马旭强; 陈留平
Original assignee: China Salt Jintan Co Ltd
Current assignee: China Salt Jintan Co Ltd
Priority date: 2018-10-25
Filing date: 2018-10-25
Publication date: 2021-03-02
Anticipated expiration: 2038-10-25
Also published as: CN109599577A

Abstract

The invention discloses a salt-cavern-based aqueous phase system organic flow battery system, which comprises two electrolyte liquid storage banks, wherein the electrolyte liquid storage banks are salt caverns which are formed after salt mines and have physical dissolved cavities, electrolyte is stored in the dissolved cavities, the electrolyte comprises a positive active substance, a negative active substance and a supporting electrolyte, and the positive active substance is a 2,2,6,6-tetramethyl piperidine oxynitride compound; the negative active material is anthraquinone compound, the positive active material and the negative active material are directly dissolved or dispersed in a system with water as solvent in a bulk form, and the supporting electrolyte is dissolved in the system; and the flow battery stack is respectively communicated with the two electrolyte liquid storage tanks. The salt-hole-based aqueous phase system organic flow battery system has the advantages of low cost, high safety performance, stable charge and discharge performance, high solubility of active materials and the like, and can also solve the problem of large-scale electrochemical energy storage and fully utilize some waste salt-hole resources.

Description

Water phase system organic flow battery system based on salt cavern

Technical Field

The invention belongs to the field of flow batteries, and particularly relates to a salt pit-based aqueous phase system organic flow battery system which can be applied to large-scale chemical energy storage.

Background

With the rapid development of human economy, the problems of environmental pollution, energy shortage and the like are increasingly aggravated, and the world countries are promoted to widely develop and utilize renewable energy sources such as wind energy, solar energy, tidal energy and the like. However, the renewable energy sources have the characteristics of discontinuity, instability, limitation by regional environment and difficult grid connection, so that the utilization rate is low, the wind and light abandoning rate is high, and resources are wasted. There is a need for a robust development of efficient, inexpensive, safe and reliable energy storage technology that can be used in conjunction therewith.

Among the various electrochemical energy storage strategies, there are static versus static batteries such as lithium ion batteriesAnd lead-acid Batteries, Flow Batteries (RFBs) have several special technical advantages, and are most suitable for large-scale (megawatt/megawatt hour) electrochemical energy storage, such as relatively independent energy and power control, large-current high-power operation (fast response), high safety performance (mainly referring to non-flammability and non-explosion), and the like. One energy storage project which is popular in China at present is a vanadium redox flow battery. China is a natural storage country of vanadium ores, and in short, vanadium raw materials for vanadium flow batteries are not a problem. But considering the limited vanadium ore resources on a global scale and the high vanadium ore price (V)₂O₅And 20/kg), the popularization and long-term use of the vanadium flow battery are difficult to realize. Vanadium flow batteries and zinc-bromine flow batteries are both traditional flow battery technologies and have some technical defects: such as self-discharge and low coulombic efficiency due to the shuttling effect of the active material between the electrodes; corrosive electrolytes are not environmentally friendly and have potential safety hazards. The cost of vanadium flow batteries is about $ 450/kilowatt hour, and the popularization price of electrochemical energy storage recommended by the U.S. department of energy is below $ 150/kilowatt hour, which means that a high-performance, economically applicable and brand-new flow battery technology is developed.

The salt cavern is an underground cavern left after salt mine exploitation in a water-soluble mode, the shape and the size of the underground cavern are determined according to different geological conditions, the volume is large, the sealing is good, and the volume is generally 10⁷～10⁸m³Therefore, the salt cavern provides a huge and safe underground space for storing electrolyte, the salt cavern is mainly used for storing natural gas and petroleum, but at present, many salt caverns in China are basically in an empty state because the technical indexes of the salt caverns cannot meet the technical requirements of oil storage or gas storage. The electrolyte stored in the water phase system by utilizing the salt cavern has lower requirements on the sealing property, the pressure resistance and the stability of the salt cavern. Therefore, the salt cavern is used for storing the electrolyte, so that the comprehensive utilization of the salt cavern can be fully realized. However, there is still a need for development of battery systems suitable for salt cavern systems (using in situ generated electrolytes).

At present, the aqueous phase flow battery still faces some challenges, especially the design of molecular materials, such as limited solubility of active materials (organic matters), easy cross contamination of electrolyte, low operating current density, easy occurrence of side reaction of water electrolysis, and the like. Therefore, it is important to develop a flow battery that overcomes the above disadvantages and can be potentially applied to a large-scale salt cavern aqueous system flow battery.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art.

Therefore, the invention provides a salt-cavity-based aqueous phase system organic flow battery system which has the advantages of low cost, high safety performance, stable charge and discharge performance, high solubility of active materials and the like.

The salt-cavern-based aqueous phase system organic flow battery system comprises two electrolyte liquid storage banks which are oppositely arranged at intervals, wherein the electrolyte liquid storage banks are salt caverns which are formed after salt mines and have physical dissolving cavities, electrolyte is stored in the dissolving cavities, the electrolyte comprises a positive active substance, a negative active substance and a supporting electrolyte, and the positive active substance is a 2,2,6,6-tetramethylpiperidine oxynitride compound; the negative active material is an anthraquinone compound, the positive active material and the negative active material are directly dissolved or dispersed in a system using water as a solvent in a bulk form and are respectively stored in the two salt holes, and the supporting electrolyte is dissolved in the system; the flow battery stack is respectively communicated with the two electrolyte liquid storages; the flow cell stack includes: the electrolytic cell body is filled with the electrolyte; the two polar plates are oppositely arranged; the battery diaphragm is positioned in the electrolytic cell body, the battery diaphragm divides the electrolytic cell body into an anode area communicated with one electrolyte liquid storage and a cathode area communicated with the other electrolyte liquid storage, one polar plate is arranged in the anode area, the other polar plate is arranged in the cathode area, a positive electrolyte containing the positive active substance is arranged in the anode area, a negative electrolyte containing the negative active substance is arranged in the cathode area, and the battery diaphragm can be penetrated by the supporting electrolyte to prevent the positive active substance and the negative active substance from penetrating; the circulating pipeline inputs or outputs the electrolyte in one electrolyte storage reservoir to or from the anode region, and the circulating pipeline inputs or outputs the electrolyte in the other electrolyte storage reservoir to or from the cathode region; and the circulating pump is arranged on the circulating pipeline and enables the electrolyte to circularly flow and be supplied through the circulating pump.

The salt-cave-based aqueous phase system organic flow battery system disclosed by the embodiment of the invention has the advantages of low cost, high safety performance, stable charge and discharge performance, high solubility of active materials and the like. And the flow battery energy storage system can solve the problem of large-scale (megawatt/megawatt hour) electrochemical energy storage and can also fully utilize some waste salt cavern (ore) resources.

According to one embodiment of the present invention, the concentration of the positive electrode active material is 0.05mol · L^-1～3.0mol·L^-1The concentration of the negative electrode active material is 0.05 mol.L^-1～4.0mol·L^-1。

According to one embodiment of the invention, the electrolyte reservoir is a sealed container.

According to one embodiment of the invention, inert gas is introduced into the electrolyte reservoir for protection.

According to one embodiment of the invention, the inert gas is nitrogen or argon.

According to one embodiment of the invention, the battery separator is a polymer porous membrane with a pore size of 10nm to 300 nm.

According to an embodiment of the present invention, the polymer porous membrane includes one of a polypropylene PP membrane, a polytetrafluoroethylene PTFE membrane, a polyvinylidene fluoride PVDF membrane, a silicon-based polypropylene PP membrane, a polyethylene PE membrane, a polystyrene PS membrane, and a polymethyl methacrylate PMMA membrane.

According to one embodiment of the invention, the battery separator is silicon-based PP, PE or PVDF.

According to one embodiment of the invention, the pore size of the battery separator is 150nm to 200 nm.

According to one embodiment of the invention, the supporting electrolyte is a NaCl salt solution, a KCl salt solution, Na₂SO₄Salt solution, K₂SO₄Salt solution, MgCl₂Salt solution, MgSO₄Salt solution, CaCl₂At least one salt solution.

According to one embodiment of the invention, the supporting electrolyte has a molar concentration of 0.1mol · L^-1～8.0mol·L^-1。

According to one embodiment of the invention, the electrolyte further comprises: an additive which is a pH adjuster or a viscosity modifier, the additive being dissolved in the system.

According to one embodiment of the invention, the pH regulator is NaOH, KOH, Na₂CO₃And at least one of CaO.

According to one embodiment of the invention, the pH range of the pH adjusting agent is: the pH value is more than or equal to 8.5 and less than or equal to 14.0.

According to one embodiment of the invention, the additive is at least one of hydroxyethyl cellulose, hydroxypropyl methyl cellulose, polyacrylamide, sodium carboxymethyl cellulose, polyethylene oxide, modified starch, polyvinyl alcohol and polyvinylpyrrolidone, and the viscosity of the electrolyte after the additive is added is 1 mPas-10 at a temperature of 25 DEG C⁶mPas。

According to one embodiment of the invention, the viscosity of the electrolyte is 10 at a temperature of 25 deg.C²mPas～10⁴mPas。

According to one embodiment of the invention, the plates are formed as graphite felt.

According to one embodiment of the invention, the thickness of the plate is 2mm to 8 mm.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic structural diagram of a salt cavern based aqueous system organic flow battery system according to an embodiment of the invention;

FIG. 2 is a graph of CV for 1, 4-dihydroxyanthraquinone at various scan rates in accordance with an embodiment of the present invention;

FIG. 3 is a plot of peak current versus scan rate raised to the power of one-half of the peak current for 1, 4-dihydroxyanthraquinone according to one embodiment of the present invention;

FIG. 4 is a graph of CV for 4-OH-TEMPO at different scan rates according to an embodiment of the present invention;

FIG. 5 is a plot of peak 4-OH-TEMPO current versus scan rate to the power of one-half according to an embodiment of the present invention;

FIG. 6 is a CV diagram of a positive electrode of 4-OH-TEMPO and a negative electrode of 1, 4-dihydroxyanthraquinone in accordance with an embodiment of the present invention;

fig. 7 is a battery cycle stability diagram according to example 1 of the present invention.

Reference numerals:

a salt cavern based aqueous system organic flow battery system 100;

an electrolyte reservoir 10;

a flow cell stack 20; a pole plate 21; the positive electrode electrolyte 22; the negative electrode electrolyte 23; a battery separator 24; a circulation line 25; a circulation pump 26.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it is to be understood that the terms "central," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the invention and to simplify the description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The following describes in detail an aqueous system organic flow battery system 100 based on salt caverns according to an embodiment of the invention with reference to the drawings.

As shown in fig. 1, the salt cavern-based aqueous system organic flow battery system 100 according to the embodiment of the invention includes two electrolyte reservoirs 10 and a flow battery stack 20, and the flow battery stack 20 includes two electrode plates 21, an electrolyte tank body, a battery diaphragm 24, a circulation pipeline 25 and a circulation pump 26.

Specifically, two electrolyte liquid storage banks 10 are oppositely arranged at intervals, the electrolyte liquid storage banks 10 are salt cavities with physical dissolving cavities formed after salt mines are mined, electrolyte is stored in the dissolving cavities, the electrolyte comprises a positive electrode active substance, a negative electrode active substance and a supporting electrolyte, and the positive electrode active substance is a 2,2,6,6-tetramethylpiperidine oxynitride (2,2,6,6-tetramethylpiperidine-1-oxyl, TEMPO) compound; the negative active substance is anthraquinone compound, the positive active substance and the negative active substance are directly dissolved or dispersed in a system using water as solvent in a body form and are respectively stored in two salt holes, supporting electrolyte is dissolved in the system, the flow battery stack 20 is respectively communicated with two electrolyte liquid storage banks 10, electrolyte is filled in the electrolytic cell body, two polar plates 21 are oppositely arranged, a battery diaphragm 24 is positioned in the electrolytic cell body, the battery diaphragm 24 divides the electrolytic cell body into an anode region communicated with one electrolyte liquid storage bank 10 and a cathode region communicated with the other electrolyte liquid storage bank 10, one polar plate 21 is arranged in the anode region, the other polar plate 21 is arranged in the cathode region, positive electrolyte 22 containing positive active substance is arranged in the anode region, negative electrolyte 23 containing negative active substance is arranged in the cathode region, the battery diaphragm 24 can be penetrated by the supporting electrolyte, the penetration of the positive electrode active material and the negative electrode active material is prevented, the electrolyte in one electrolyte reservoir 10 is input or output to the anode region through the circulation pipeline 25, the electrolyte in the other electrolyte reservoir 10 is input or output to the cathode region through the circulation pipeline 25, and the circulation pump 26 is provided in the circulation pipeline 25 and circulates and supplies the electrolyte through the circulation pump 26.

In other words, the salt-pit-based aqueous-phase-system organic flow battery system 100 according to the embodiment of the invention includes two electrolyte reservoirs 10 and a flow battery stack 20, the flow battery stack 20 includes two electrode plates 21, a battery cell body, a battery diaphragm 24, a circulation pipeline 25 and a circulation pump 26, the electrolyte reservoirs 10 are underground pits, namely salt pits, left after salt mine mining in a water-soluble manner, electrolyte is stored in the salt pits, the electrolyte includes a positive active material, a negative active material and a supporting electrolyte, the positive active material in the anode electrolyte is a 2,2,6,6-tetramethylpiperidine oxynitride (2,2,6,6-tetra-methylpiperidine-1-oxyl, TEMPO) type compound (a), the negative active material in the cathode electrolyte is an anthraquinone type compound (B), the positive active material and the negative active material are directly dissolved or dispersed in a bulk form in a system using water as a solvent, supporting electrolyte is dissolved in a system, a flow battery stack 20 is respectively communicated with two electrolyte liquid storage banks 10 through a circulating pipeline 25, two polar plates 21 are oppositely arranged, a circulating pump 26 is arranged on the circulating pipeline 25, the electrolyte circularly flows to the polar plates 21 through the circulating pump 26, the two polar plates 21 can be respectively a positive electrode and a negative electrode, the polar plates 21 are directly contacted with the electrolyte, an electrochemical reaction site with rich pores is provided, a battery diaphragm 24 is positioned between electrolytic cell bodies, the battery diaphragm 24 can support the penetration of the electrolyte, the penetration of positive active substances and negative active substances is prevented, and the battery diaphragm 24 can be a cation exchange membrane.

The structures of the TEMPO-based compound (a) and the anthraquinone-based compound (B) are as follows:

wherein, the substituent group R₁Is OH, OMe, OEt, CHO, NH₂、N(Me)₂、N(Et)₂、F、Cl、CN、NO₂、COOH、SO₃H or one of other grafted macromolecular compounds; substituent group R₂And R₃Can be one of mono-substitution or multi-substitution on a benzene ring, and the described substituent group R₂And R₃Is OH, OMe, OEt, CHO, NH₂、N(Me)₂、N(Et)₂、F、Cl、CN、NO₂、COOH、SO₃H or one or more of other grafted macromolecular compounds; the substituent group R₂And R₃May be the same or different.

Therefore, the salt-cavity-based aqueous phase system organic flow battery system 100 according to the embodiment of the invention adopts a device combining two electrolyte liquid storage reservoirs 10 and a flow battery stack 20, and the flow battery stack 20 adopts a device combining two polar plates 21, an electrolytic cell body, a battery diaphragm 24, a circulating pipeline 25 and a circulating pump 26, so that the problems of high cost, non-environmental protection of corrosive electrolyte and potential safety hazard of the current flow battery, limited solubility of active materials (organic matters), easy cross contamination of electrolyte, low operating current density, easy occurrence of water electrolysis side reaction and the like of the current aqueous phase system are overcome, the salt-cavity-based aqueous phase system organic flow battery system 100 according to the embodiment of the invention constructs an aqueous phase system flow battery system which respectively takes 2,2,6,6-Tetramethylpiperidine (TEMPO) compounds and anthraquinone compounds as redox active components, the system can be suitable for the battery environment of a salt cavern system (by using electrolyte generated in situ), the battery system 100 has the advantages of low cost, high safety performance, stable charging and discharging performance, high solubility of active materials and the like, and the energy storage system of the flow battery can solve the problem of large-scale (megawatt/megawatt hour) electrochemical energy storage and can fully utilize some waste salt cavern (ore) resources.

According to one embodiment of the present invention, the concentration of the positive electrode active material is 0.05mol · L^-1～3.0mol·L^-1The concentration of the negative electrode active material was 0.05 mol. L^-1～4.0mol·L^-1。

In some embodiments of the invention, the electrolyte reservoir 10 is a sealed container.

According to one embodiment of the present invention, the electrolyte reservoir 10 is protected by an inert gas.

Further, the inert gas is nitrogen or argon.

According to one embodiment of the present invention, the battery separator 24 is a membrane prepared according to the sieving principle, and the battery separator 24 may be a polymer porous membrane having a pore size of 10nm to 300 nm.

Optionally, the polymer porous membrane comprises one of a polypropylene PP membrane, a polytetrafluoroethylene PTFE membrane, a polyvinylidene fluoride PVDF membrane, a silicon-based polypropylene PP membrane, a polyethylene PE membrane, a polystyrene PS membrane, and a polymethyl methacrylate PMMA membrane.

Further, the battery separator 24 is silicon-based PP, PE or PVDF.

According to one embodiment of the invention, the pore size of the battery separator 24 is between 150nm and 200 nm.

In some embodiments of the invention, the supporting electrolyte is a NaCl salt solution, a KCl salt solution, Na₂SO₄Salt solution, K₂SO₄Salt solution, MgCl₂Salt solution, MgSO₄Salt solution, CaCl₂At least one salt solution.

Further, a supporting electrolyteHas a molar concentration of 0.1 mol.L^-1～8.0mol·L^-1。

According to one embodiment of the invention, the electrolyte further comprises an additive, the additive being a pH adjuster or a viscosity modifier, the additive being dissolved in the system.

Optionally, the pH regulator is NaOH, KOH, Na₂CO₃And at least one of CaO.

In some embodiments of the present invention, the additive is at least one of hydroxyethyl cellulose, hydroxypropyl methylcellulose, polyacrylamide, sodium carboxymethylcellulose, polyethylene oxide, modified starch, polyvinyl alcohol, and polyvinylpyrrolidone, and the viscosity of the electrolyte solution after the additive is added is 1mPas to 10 mPas measured by a rotational viscometer at 25 ℃⁶mPas。

Further, the viscosity of the electrolyte was 10 at a temperature of 25 deg.C²mPas～10⁴mPas。

According to one embodiment of the invention, the plates 21 are formed as graphite felt.

Optionally, the plate 21 has a thickness of 2mm to 8 mm.

The salt cavern-based aqueous system organic flow battery system 100 according to the embodiment of the invention is specifically described below with reference to specific examples.

In cyclic voltammetry testing of the galvanic couple, a CS series electrochemical workstation of Wuhan Corset company is adopted to test the electrochemical performance of the organic galvanic couple by a three-electrode system. The working electrode is a glassy carbon electrode (Tianjin Elata Heng Cheng corporation), the reference electrode is an Ag/AgCl electrode, and the counter electrode is a platinum electrode. The scanning ranges of the positive and negative electrode pairs are respectively-1.0V, and the scanning speed is 20mV s^-1，40mV·s^-1，60mV·s^-1，80mV·s^-1，100mV·s^-1. The CV of the negative electrode couple is shown in fig. 2, and a linear fit of the redox peak current to the half power of the scan rate is shown in fig. 3. CV of positive electrode couple is shown in FIG. 4, and the redox peak current is linearly fitted to the scan rate to the power of one-halfSee fig. 5.

In the cell test, the flow rate of the electrolyte was about 5.0 mL-min^-1The current density is 0.5mA cm under the constant current charge-discharge mode^-2。

Example 1

The negative electrode active material in the negative electrode electrolyte 23 was 0.05 mol. L^-11, 4-dihydroxyanthraquinone, 0.05 mol. L of the positive electrode active material in the positive electrode electrolyte 22^-12.5 mol. L of supporting electrolyte in the 4-OH-TEMPO, the positive electrolyte 22 and the negative electrolyte 23 are adopted^-1The pH of the sodium chloride solution is adjusted to 14.0 by using NaOH, and the coulombic efficiency, the voltage efficiency and the energy efficiency of the single cell of the salt-cavern-based aqueous system organic flow battery system (i) are shown in table 1.

Example 2

The negative electrode active material in the negative electrode electrolyte 23 was 0.05 mol. L^-11, 4-dihydroxyanthraquinone, 0.05 mol. L of the positive electrode active material in the positive electrode electrolyte 22^-12.5 mol. L of supporting electrolyte in the 4-OH-TEMPO, the positive electrolyte 22 and the negative electrolyte 23 are adopted^-1The pH of the sodium carbonate solution is adjusted to 14.0 by using KOH, and the coulombic efficiency, voltage efficiency and energy efficiency of the unit cell of the salt-cavern-based aqueous system organic flow battery system (ii) are shown in table 1.

Example 3

The negative electrode active material in the negative electrode electrolyte 23 was 0.1 mol. L^-11, 4-dihydroxyanthraquinone, 0.1 mol. L of the positive electrode active material in the positive electrode electrolyte 22^-12.5 mol. L of supporting electrolyte in the 4-OH-TEMPO, the positive electrolyte 22 and the negative electrolyte 23 are adopted^-1The pH of the solution was adjusted to 14.0 with NaOH, and the coulombic efficiency, voltage efficiency and energy efficiency of the unit cell of the salt-sink-based aqueous organic flow battery system (iii) assembled are shown in table 1.

Example 4

The negative electrode active material in the negative electrode electrolyte 23 was 0.1 mol. L^-11-hydroxy-4- (p-toluidine) anthraquinone, and the positive electrode active material in the positive electrode electrolyte 22 is 0.1mol·L^-12.5 mol.L of the supporting electrolyte in the 4-OH-TEMPO potassium cyanide, the positive electrolyte 22 and the negative electrolyte 23 are adopted^-1The pH of the sodium chloride solution is adjusted to 14.0 by using NaOH, and the coulombic efficiency, the voltage efficiency and the energy efficiency of the single cell of the salt-cavern-based aqueous system organic flow battery system (iv) are shown in table 1.

Example 5

The negative electrode active material in the negative electrode electrolyte 23 was 0.05 mol. L^-11, 4-dihydroxyanthraquinone, 0.05 mol. L of the positive electrode active material in the positive electrode electrolyte 22^-12.5 mol. L of the supporting electrolyte in the 1-oxyl-TEMPO solution, the positive electrolyte 22 and the negative electrolyte 23 are used^-1The pH of the solution was adjusted to 13.0 with KOH, and the coulombic efficiency, voltage efficiency, and energy efficiency of the cells of the salt-sink based aqueous organic flow battery system (v) assembled are shown in table 1.

Example 6

The negative electrode active material in the negative electrode electrolyte 23 was 0.1 mol. L^-11-hydroxy-4- (p-toluidine) anthraquinone, and the amount of the positive electrode active material in the positive electrode electrolyte 22 is 0.1mol · L^-12.5 mol. L of the supporting electrolyte in the 1-oxyl-TEMPO solution, the positive electrolyte 22 and the negative electrolyte 23 are used^-1The pH of the sodium carbonate solution is adjusted to 12.0 by NaOH, and the coulombic efficiency, the voltage efficiency and the energy efficiency of a single cell of the salt-cavity-based aqueous phase system organic flow battery system (VI) are shown in Table 1.

Example 7

The negative electrode active material in the negative electrode electrolyte 23 was 0.1 mol. L^-11-aminoanthraquinone, and the amount of the positive electrode active material in the positive electrode electrolyte 22 is 0.1mol · L^-1TEMPO, 2.5 mol. L for the supporting electrolyte in the positive electrolyte 22 and the negative electrolyte 23^-1The pH of the solution was adjusted to 12.0 with KOH, and the coulombic efficiency, voltage efficiency, and energy efficiency of the cells of the salt-sink based aqueous organic flow battery system (vii) assembled are shown in table 1.

Example 8

The negative electrode active material in the negative electrode electrolyte 23 was 0.2 mol. L ^-12, 5-diaminoanthraquinone, and the positive electrode active material in the positive electrode electrolyte 22 is 0.2mol · L^-12.5 mol. L of supporting electrolyte in the 4-OH-TEMPO, the positive electrolyte 22 and the negative electrolyte 23 are adopted^-1Adjusting the pH of the solution to 12.0 by using KOH, and adjusting the viscosity of the electrolyte to 10 by using hydroxypropyl methyl cellulose²The coulombic efficiency, the voltage efficiency and the energy efficiency of the single cells of the assembled salt-cavern-based aqueous system organic flow battery system (VIII) are shown in the table 1.

TABLE 1 comparison of cell Performance

	Coulombic efficiency (%)	Voltage efficiency (%)	Energy efficiency (%)
				(Ⅰ)	91.4	81.5	75.0
(Ⅱ)	91.2	81.4	74.7
				(Ⅲ)	90.9	81.0	74.1
(Ⅳ)	90.6	81.3	73.8
				(Ⅴ)	90.7	81.4	73.5
(Ⅵ)	91.2	81.3	74.3
				(Ⅶ)	90.8	81.2	74.1
(Ⅷ)	91.3	81.4	74.6

As can be seen from table 1, the organic electrochemical activity and the reversibility of the positive and negative electrode pairs were good. As can be seen from FIG. 6, 1, 4-dihydroxyanthraquinone exhibited quasi-reversible redox electrochemistry with a pair of redox peaks between-0.8V and-0.5V, a standard potential of about-0.72V, and a potential difference between the oxidation peak potential and the reduction peak potential of about 50 mV. 4-OH-TEMPO has a pair of oxidation-reduction peaks between 0.4V and 0.8V, the standard potential is about 0.61V, and the potential difference between the oxidation peak potential and the reduction peak potential is about 60mV, thus showing quasi-reversible redox electrochemistry. The linear fitting is carried out on the positive and negative electrode couples respectively to the half power of the peak current and the sweep rate in the oxidation process and the reduction process, and the oxidation-reduction processes of the positive and negative electrode couples are controlled by the diffusion of electrochemical active substances.

Thus, each example exhibited good electrical conductivity, and as can be seen from fig. 7, the assembled cell was stable in efficiency and good in cycle performance. In summary, the salt-sink-based aqueous-phase organic flow battery system 100 according to the embodiment of the present invention has the advantages of low cost, high safety performance, stable charging and discharging performance, high solubility of active materials, and the like, and can also solve the problem of large-scale electrochemical energy storage and fully utilize some waste salt-sink resources.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an illustrative embodiment," "an example," "a specific example," or "some examples" or the like mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An aqueous phase system organic flow battery system based on salt cavern, which is characterized by comprising:

the electrolyte comprises two electrolyte liquid storage banks, wherein the two electrolyte liquid storage banks are oppositely arranged at intervals, each electrolyte liquid storage bank is a salt cavity which is formed after salt mines are mined and is provided with a physical dissolving cavity, electrolyte is stored in the dissolving cavity, the electrolyte comprises a positive active substance, a negative active substance and supporting electrolyte, and the positive active substance is a 2,2,6,6-tetramethylpiperidine oxynitride compound; the negative active material is an anthraquinone compound, the positive active material and the negative active material are directly dissolved or dispersed in a system using water as a solvent in a bulk form and are respectively stored in the two salt holes, and the supporting electrolyte is dissolved in the system;

the flow battery stack is respectively communicated with the two electrolyte liquid storages;

the flow cell stack includes:

the electrolytic cell body is filled with the electrolyte;

the two polar plates are oppositely arranged;

the battery diaphragm is positioned in the electrolytic cell body, the battery diaphragm divides the electrolytic cell body into an anode area communicated with one electrolyte liquid storage and a cathode area communicated with the other electrolyte liquid storage, one polar plate is arranged in the anode area, the other polar plate is arranged in the cathode area, a positive electrolyte containing the positive active substance is arranged in the anode area, a negative electrolyte containing the negative active substance is arranged in the cathode area, and the battery diaphragm can be penetrated by the supporting electrolyte to prevent the positive active substance and the negative active substance from penetrating;

the circulating pipeline inputs or outputs the electrolyte in one electrolyte storage reservoir to or from the anode region, and the circulating pipeline inputs or outputs the electrolyte in the other electrolyte storage reservoir to or from the cathode region;

and the circulating pump is arranged on the circulating pipeline and enables the electrolyte to circularly flow and be supplied through the circulating pump.

2. The salt cavern-based aqueous-phase-system organic flow battery system as claimed in claim 1, wherein the concentration of the positive active material is 0.05 mol-L^-1～3.0mol·L^-1The concentration of the negative electrode active material is 0.05 mol.L^-1～4.0mol·L^-1。

3. The salt cavern-based aqueous organic flow battery system of claim 1, wherein the electrolyte reservoir is a sealed container.

4. The salt cavern-based aqueous system organic flow battery system as claimed in claim 1, wherein inert gas is introduced into the electrolyte reservoir for protection.

5. The salt cavern-based aqueous organic flow battery system of claim 4, wherein the inert gas is nitrogen or argon.

6. The salt cavern-based aqueous system organic flow battery system as claimed in claim 1, wherein the battery separator is a polymer porous membrane with a pore size of 10nm to 300 nm.

7. The salt cavern-based aqueous system organic flow battery system of claim 6, wherein the polymer porous membrane comprises one of a polypropylene (PP) membrane, a Polytetrafluoroethylene (PTFE) membrane, a polyvinylidene fluoride (PVDF) membrane, a silicon-based polypropylene (PP) membrane, a Polyethylene (PE) membrane, a Polystyrene (PS) membrane, and a polymethyl methacrylate (PMMA) membrane.

8. The salt cavern-based aqueous system organic flow battery system of claim 7, wherein the battery separator is silicon-based PP, PE, or PVDF.

9. The salt cavern-based aqueous system organic flow battery system of claim 8, wherein the battery separator has a pore size of 150nm to 200 nm.

10. The salt cavern-based aqueous system organic flow battery system of claim 1, wherein the support comprisesThe electrolyte is NaCl salt solution, KCl salt solution, Na₂SO₄Salt solution, K₂SO₄Salt solution, MgCl₂Salt solution, MgSO₄Salt solution, CaCl₂At least one salt solution.

11. The salt cavern-based aqueous system organic flow battery system of claim 10, wherein the molar concentration of the supporting electrolyte is 0.1 mol-L^-1～8.0mol·L^-1。

12. The salt cavern-based aqueous organic flow battery system of claim 1, wherein the electrolyte further comprises:

an additive which is a pH adjuster or a viscosity modifier, the additive being dissolved in the system.

13. The salt cavern-based aqueous system organic flow battery system of claim 12, wherein the pH regulator is NaOH, KOH, Na₂CO₃And at least one of CaO.

14. The salt cavern-based aqueous system organic flow battery system of claim 13, wherein the pH of the pH adjuster is in the range of: the pH value is more than or equal to 8.5 and less than or equal to 14.0.

15. The salt cavern-based aqueous phase system organic flow battery system as claimed in claim 12, wherein the additive is at least one of hydroxyethyl cellulose, hydroxypropyl methylcellulose, polyacrylamide, sodium carboxymethyl cellulose, polyethylene oxide, modified starch, polyvinyl alcohol and polyvinylpyrrolidone, and the viscosity of the electrolyte after the additive is added is 1 mPas-10 mPas at 25 ℃⁶mPas。

16. The salt cavern-based aqueous system organic flow battery system of claim 15, wherein the salt cavern-based aqueous system organic flow battery system comprisesCharacterized in that the viscosity of the electrolyte is 10 at a temperature of 25 DEG C²mPas～10⁴mPas。

17. The salt cavern based aqueous system organic flow battery system of claim 1, wherein the plate is formed as a graphite felt.

18. The salt cavern-based aqueous organic flow battery system of claim 17, wherein the plate has a thickness of 2mm to 8 mm.