CN117712439A - Redox organic flow batteries for energy storage and their applications - Google Patents

Abstract

The invention provides an oxidation-reduction organic flow battery for energy storage and application thereof; the redox organic flow battery for energy storage comprises two electrolyte storage tanks of positive electrode and negative electrode electrolyte, wherein the two electrolyte storage tanks are respectively connected with an inert electrode and are separated by a diaphragm with ion exchange capability; the redox organic flow battery is characterized in that the negative electrode electrolyte of the redox organic flow battery comprises 0.01-99.99% of a component in formula 1; the redox organic flow battery for energy storage not only has excellent performance in the cycle of single electron transfer redox reaction as battery charge and discharge, but also has excellent performance in the redox reaction of double electron transfer.

Description

Redox organic flow batteries for energy storage and their applications

Technical field

The invention belongs to the field of flow batteries, and specifically relates to redox organic flow batteries for storing electrical energy and their applications.

Background technique

The rapid development of society cannot be separated from the support of traditional fossil energy. Its non-renewable and pollution problems have created a high demand for sustainable renewable energy, prompting the rapid development of green energy technology. The instability and discontinuity of scenery and tidal energy restrict their application fields. Therefore, scientists focus on developing energy storage technology to achieve stable, safe and controllable energy output by converting green energy into physical energy and chemical energy. Batteries are particularly suitable for energy storage applications such as redox flow batteries for storing electrical energy as emergency backup power supplies, stationary storage for peak load regulation from renewable energy sources, especially in the photovoltaic and wind industry or Intermediate storage of discontinuous and unstable electrical energy such as biomass power plants, tidal power plants or marine power plants.

Redox flow batteries are electrochemical energy stores. The compounds required for establishing the potential at the electrode are dissolved redox-active species which are converted into their respective other redox states in the electrochemical reactor during charging or discharging. Compared with the redox couples (redox active compounds) of low-molecular inorganic compounds used in previous redox flow batteries, the redox couples of organic and partially organic components are more attractive, such as the disclosed anthraquinone-bis Sulfonic acid/bromine systems, which allow very high current densities, however impose high requirements on the materials and system safety of all battery components due to the use of elemental bromine (B. Huskinson, M.P. Marshak, C. Suh, S. ErM.R.Gerhardt, C.J.Galvin, While other electrolyte systems such as LiPF6 and TEMPO (X.wie, w.Xu, M.Vijayakumar, L.Cosimbescu, T.Liu, v.Sprenkle, W.Wang: "TEMPO-based Catholyte for high-energydensitiy redox flowbatteries" Adv. Mater.2014Vol.26,45,p7649-7653) are also based on organic solvents and conductive salts, which will release toxic gases such as hydrogen fluoride in case of failure, thus placing high requirements on system safety. In addition, the organic redox pair used in the early stage mainly uses single-electron transfer redox reaction as the main reaction of the battery in organic flow batteries. Energy storage batteries promoted by multi-electron transfer redox reactions have higher energy storage efficiency.

The purpose of this patented invention is to provide a new type of redox organic flow battery and its application, which can operate safely, at low cost and with high efficiency. Its advantage is that the active materials of the positive and negative electrolytes are organic substances, and the structure can be adjusted. The size is generally larger than that of metal ions, so the requirements for separators become lower; and the supporting electrolyte of its organic flow battery can be a neutral solution such as dilute acid, dilute alkali or water, so that some components of the battery can reduce anti-corrosion requirements, and at the same time also This means cost reduction and life extension; at the same time, the double electron transfer redox reaction can be used as the main reaction of the energy storage battery, which greatly improves the energy storage efficiency of the battery.

Contents of the invention

In order to solve the above problems, the present invention discloses a redox organic flow battery for storing electrical energy and its application. The redox organic flow battery for energy storage not only performs the redox reaction of single electron transfer as a battery charge and discharge It has excellent performance in the cycle, and also has excellent performance in the redox reaction of double electron transfer.

In order to achieve the above objects, the technical solutions of the present invention are as follows:

The invention provides a redox organic liquid flow battery for energy storage, which includes a positive electrolyte storage tank and a negative electrolyte storage tank, in which redox-active organic compounds or redox-active compounds are stored in two electrolytes respectively. The electrolyte solvent in the pool exists in a dissolved form or a dispersed manner. The positive electrolyte storage pool and the negative electrolyte storage pool are respectively connected to the inert electrodes. The two electrolyte storage pools are separated by a separator with ion exchange capability. , the negative electrolyte contains 0.01%-99.99% of Formula 1 or its redox active material. The structure of Formula 1 is as follows:

;

in,

R1 and R2 independently represent an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a haloaryl group, an aralkyl group or a heterocyclic group; preferably, R1 and R2 independently represent a methyl group;

a and b are independent integers from 0 to 4, and a and b cannot be 0 at the same time;

M is an inorganic or organic anion in n valence state and a mixture of such anions;

n is an integer from 1 to 10.

Further, the negative electrolyte also includes formula 2 or its redox active material;

in,

R1 and R2 independently represent an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a haloaryl group, an aralkyl group or a heterocyclic group;

M is an inorganic or organic anion in n valence state and a mixture of such anions;

n is an integer from 1 to 10;

R ₃ represents a hydrogen atom, an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, an aralkyl group, a haloaryl group, a halogen, an amino group, a nitro group or a cyano group.

Further, the positive electrolyte includes a redox active material of ferrocyanide metal and ammonium salt; preferably, the positive electrolyte uses a ferrocyanide metal salt or an ammonium ferrocyanide salt as a redox active material.

Further, the electrolyte also includes neutral solvents and additives; neutral solvents include organic solvents, weak acid solvents, weak alkali solvents, water or inorganic salt solutions, and additives include surfactants, viscosity improvers, pesticides, buffers, and stabilizers. , catalysts, phase transfer addition catalysts, antifreeze, heat stabilizers and defoaming agents.

Further, the neutral solvent can be dilute sulfuric acid solution, dilute sodium hydroxide solution, alcohol (such as ethanol), nitrile (such as acetonitrile) or sodium chloride aqueous solution, etc. Preferably, the neutral solvent is sodium chloride aqueous solution.

Further, the additives include surfactants, which may be alkyl polyglucosides, alkyl glucosides, saponins or phospholipids.

Further, the additives include buffers, which may be phosphate buffers, acetic acid-acetate buffers, citric acid buffers or citrate buffers, etc.

The redox organic flow battery of the present invention includes a separator with ion exchange capability, including an anion exchange membrane, a cation exchange membrane, and a porous membrane. For better stability, frame-shaped, sieve-shaped and other attached supports can be added.

In addition to the above-mentioned electroactive components, electrolytes and separators, the redox organic flow battery of the present invention also includes other components. Here it is:

Delivery mechanisms, such as pumps, and tanks and tubes for transporting and storing electrolyte and the redox-active components therein;

An electrode, preferably consisting of or containing the following: carbon rods, carbon nanotubes, activated carbon, carbon black or graphene;

An optional current collector is made, for example, of graphite or of metal.

Further, the structure of Formula 1 is as follows:

.

Further, the preparation method includes the following steps:

(1) Add catalyst Pd-C and hydrazine hydrate to 4-bromo-2methylpyridine, and react under nitrogen atmosphere to obtain 2,2'-dimethyl-4,4'-bipyridine; 4-bromo-2methyl The mass ratio of pyridine, catalyst Pd-C, and hydrazine hydrate is 1:0.001-0.02:0.8-1.5;

;

(2) Add bromobenzene and tin dioxide to 2,2'-dimethyl-4,4'-bipyridine to react to obtain [4,4'-bipyridine]-2,2'-dicarboxylic acid; 2 , the mass ratio of 2'-dimethyl-4,4'-bipyridine, bromobenzene, and tin dioxide is 1:6-10:2-4;

;

(3) Add methanol and concentrated sulfuric acid to the [4,4'-bipyridine]-2,2'-dicarboxylic acid obtained in step (2), and perform a reflux reaction to obtain [4,4'-bipyridine]-2, The mass ratio of 2'-dicarboxylic acid dimethyl ester; [4,4'-bipyridyl]-2,2'-dicarboxylic acid, methanol, and concentrated sulfuric acid is 1:0.25-0.5:3-5;

;

(4) Add acetonitrile and methyl iodide to [4,4'-bipyridyl]-2,2'-dicarboxylic acid dimethyl ester obtained in step 3, and react to obtain 2,2'-bis(methoxycarbonyl) -1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine; [4,4'-bipyridyl]-2,2'-dicarboxylic acid dimethyl ester The mass ratio of acetonitrile and methyl iodide is 1:1.5-2.5:1-2;

;

(5) Add 2,2'-bis(methoxycarbonyl)-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine obtained in step 4. Dilute sulfuric acid solution reacts to obtain 2,2'-dicarboxy-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine; 2,2'-bis(methane The mass ratio of oxycarbonyl)-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine and dilute sulfuric acid solution is 1:4-5.5;

.

The present invention also provides applications of the redox organic flow battery for energy storage. The applications include: as a fixed storage for emergency backup power supply and peak load adjustment, and for the storage of discontinuous and unstable electrical energy. Intermediate storage, and used in the field of electric mobility, the intermediate storage of discontinuous and unstable electrical energy includes the intermediate storage of electrical energy in photovoltaic power plants, wind power plants, biomass power plants, tidal power plants or ocean power plants. , the electromobility field includes storage in vehicles on land, in the air and in the water.

The beneficial effects of the present invention are:

The redox organic flow battery for energy storage of the present invention not only performs well in the redox reaction of single electron transfer as a cycle of battery charge and discharge, but also has superior performance in the redox reaction of double electron transfer. Performance; when using the double electron transfer redox reaction as the main reaction of the energy storage battery, the energy storage efficiency of the battery is greatly improved.

Description of the drawings

Figure 1 is a cyclic voltammogram of the active material synthesized in Example 1, in which a carbon rod is used as the working electrode, a platinum wire is used as the counter electrode and a silver/silver chloride electrode is used as a reference; as the electrolyte, a sodium chloride aqueous solution is used (0.5mol/L);

Figure 2 is a charging curve during charge and discharge cycles of the redox organic flow battery composed in Example 3.

Detailed ways

The present invention will be further clarified below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

Example 1

Electrolyte active material: synthesis of 2,2'-dicarboxy-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine (6)

;

Synthetic steps

Step 1: Synthesis of 2,2'-dimethyl-4,4'-bipyridine (2)

In a 500mL flask, add 51.6g of 4-bromo-2methylpyridine (1) dissolved in 150mL of DMF, add 0.5g of Pd-C catalyst, add 50g of hydrazine hydrate (80%), react for 12h under nitrogen atmosphere, and wait for the reaction At the end, use a rotary evaporator to remove the solvent and water, and use column chromatography to obtain 23.5g of the product 2,2'-dimethyl-4,4'-bipyridine (2), with a yield of 85%.

Step 2: Synthesis of [4,4'-bipyridyl]-2,2'-dicarboxylic acid (3)

Add 18.4g of 2,2'-dimethyl-4,4'-bipyridine (2) obtained in step 1, 150g of bromobenzene and 60.0g of tin dioxide into a 200mL flask, and maintain the reaction at 90°C for 16 hours. Wait for the reaction to end, use a rotary evaporator to remove the solvent, dissolve the remaining solid with 10% KOH solution, filter out the insoluble matter, add 10% HCl solution to the remaining liquid to acidify, ensure the pH is <6, and extract with a small amount of ethyl acetate several times. The organic phase was collected and the solvent was removed to obtain 20.4g of the product [4,4'-bipyridine]-2,2'-dicarboxylic acid (3), with a yield of 83.2%.

Step 3: Synthesis of [4,4'-bipyridyl]-2,2'-dicarboxylic acid dimethyl ester (4)

Add 20.4g of [4,4'-bipyridine]-2,2'-dicarboxylic acid (3) obtained in step 2, 5.5g of methanol and 73.6g of concentrated sulfuric acid into a 150mL flask, and conduct a reflux reaction at 115°C for 6 hours. Wait for the reaction to end, use 10% potassium carbonate solution to neutralize and dilute the acid solution, use ethyl acetate to extract multiple times, take the organic phase, and rotary evaporate to remove the solvent to obtain the product [4,4'-bipyridyl]-2,2'- Dimethyl dicarboxylate (4) 21.5g, yield 95%.

Step 4: Synthesis of 2,2'-bis(methoxycarbonyl)-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine (5)

Add 21.5g of [4,4'-bipyridyl]-2,2'-dicarboxylic acid dimethyl ester (4) obtained in step 3, 39.3g of acetonitrile and 33.4g of methyl iodide into a 150mL flask, and react at room temperature for 48 hours. Wait for the reaction to end, use a rotary evaporator to remove the solvent and methyl iodide, and obtain the product 2,2'-bis(methoxycarbonyl)-1,1'-dimethyl-[4,4'-bipyridyl]-1,1 '-Diimine (5) 22.8g, yield 95.7%.

Step 5: Synthesis of 2,2'-dicarboxy-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine (6)

Add 22.8g of 2,2'-bis(methoxycarbonyl)-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diamidia obtained in step 4 into a 250mL flask. Amine (5) and 100g of 10% dilute sulfuric acid solution were reacted at 80°C for 24 hours. Wait for the reaction to end, add 10% potassium carbonate solution, adjust the pH to neutral, remove the solvent by rotary evaporation, add acetonitrile, filter to remove insoluble matter, and remove acetonitrile by rotary evaporation again to obtain the product 2,2'-dicarboxy-1,1 '-Dimethyl-[4,4'-bipyridyl]-1,1'-diimine (6) 18.2g, yield 18.2%.

Target product analysis data

2,2'-dicarboxy-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine (6)

¹ H NMR (400 MHz, D ₂ O, TMS) δ (ppm) 12.54 (s, 2H), 9.24 (s, 2H), 9.43 (m, 4H), 4.37 (s, 6H).

Example 2

For the active material 2,2'-dicarboxy-1,1'-dimethyl-[4,4'-bipyridyl]-1,1'-diimine (6) obtained in Example 1, it was -0.8 Cyclic voltammetry test was performed between V~1.0V, using carbon rod as working electrode, platinum wire as counter electrode and silver/silver chloride electrode as reference; the neutral solvent in the electrolyte was sodium chloride aqueous solution (0.5 mol/L), as shown in the electrolyte circulation curve in Figure 1, the sweep speed is 0.1V/s, and there are two pairs of obvious oxidation/reduction peaks, namely -0.25V oxidation peak and -0.3V reduction peak, -0.5V oxidation peak. The peak and -0.55V reduction peak correspond to the double electron transfer redox peak. Among them, the low potential peak has high symmetry, good reversibility and strong reduction property. After 5 cycles, there is almost no loss, and the active material has good stability.

Example 3

Redox flow battery pack composed of Formula 3, Formula 4 and potassium ferrocyanide

Two electrolyte solutions were prepared: the negative electrolyte solution was prepared from 12.68g of the compound of formula 3 structure, 0.19g of the compound of formula 4 structure and 731mg of sodium chloride in 25mL of deionized water; the positive electrolyte solution was prepared from 13.8g of potassium ferrocyanide and 731 mg sodium chloride in 25 mL deionized water. The electrolyte solution was tested in a redox flow battery with an active area of 5 cm, and the battery was cycled to charge and discharge. Figure 2 shows the charging curve of this battery.

.

It should be noted that the above content only illustrates the technical idea of the present invention and cannot limit the protection scope of the present invention. For those of ordinary skill in the technical field, without departing from the principle of the present invention, they can also make Several improvements and modifications are made, and these improvements and modifications fall within the protection scope of the claims of the present invention.

Claims (7)

1. An oxidation-reduction organic flow battery for energy storage, comprising a positive electrolyte storage tank and a negative electrolyte storage tank, wherein the positive electrolyte storage tank and the negative electrolyte storage tank are respectively connected with an inert electrode, and the two electrolyte storage tanks are separated by a diaphragm with ion exchange capability, and the oxidation-reduction organic flow battery is characterized in that the negative electrolyte comprises 0.01-99.99% of active substances in formula 1 or oxidation reduction thereof, and the structure of formula 1 is as follows:

；

wherein,

r1 and R2 independently of one another represent alkyl, alkoxy, haloalkyl, aryl, haloaryl, aralkyl and heterocyclyl;

a and b are each independently an integer from 0 to 4, and a and b may not be 0 at the same time;

m is an inorganic or organic anion in the n-valent state and mixtures of such anions;

n is an integer from 1 to 10.

2. The redox organic flow battery for energy storage of claim 1, wherein the negative electrolyte further comprises formula 2 or a redox active material thereof;

；

wherein,

r1 and R2 independently of one another represent alkyl, alkoxy, haloalkyl, aryl, haloaryl, aralkyl or heterocyclyl;

m is an inorganic or organic anion in the n-valent state and mixtures of such anions;

n is an integer from 1 to 10;

R ₃ represented by a hydrogen atom, an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, an aralkyl group, a haloaryl group, a halogen, an amino group, a nitro group, or a cyano group.

3. An redox organic flow battery for energy storage as claimed in claim 1 wherein the positive electrode electrolyte comprises a redox active material of a metal ferrocyanide, ammonium salt.

4. The redox organic flow battery for energy storage of claim 1, wherein the electrolyte further comprises a neutral solvent, a surfactant, a viscosity modifier, a pesticide, a buffer, a stabilizer, a catalyst, a phase transfer additive catalyst, an antifreeze, a heat stabilizer, and an antifoaming agent, the neutral solvent comprising an organic solvent, a weak acid solvent, a weak base solvent, water, or an inorganic brine solution.

5. The redox organic flow battery for energy storage of claim 1, wherein formula 1 is structured as follows:

。

6. the redox organic flow battery for energy storage of claim 5, wherein the method of preparation comprises the steps of:

(1) Adding a catalyst Pd-C and hydrazine hydrate into the 4-bromo-2-methylpyridine, and reacting in a nitrogen atmosphere to obtain 2,2 '-dimethyl-4, 4' -bipyridine;

；

(2) Adding bromobenzene and tin dioxide into 2,2 '-dimethyl-4, 4' -bipyridine, and reacting to obtain [4,4 '-bipyridine ] -2,2' -dicarboxylic acid;

；

(3) Adding methanol and concentrated sulfuric acid into the [4,4 '-bipyridine ] -2,2' -dicarboxylic acid obtained in the step (2), and carrying out reflux reaction to obtain [4,4 '-bipyridine ] -2,2' -dicarboxylic acid dimethyl ester;

；

(4) Acetonitrile and methyl iodide are added into the [4,4 '-bipyridine ] -2,2' -dicarboxylic acid dimethyl ester obtained in the step 3, and 2,2 '-bis (methoxycarbonyl) -1,1' -dimethyl- [4,4 '-bipyridine ] -1,1' -diimine is obtained by reaction;

；

(5) Adding dilute sulfuric acid solution into the 2,2 '-bis (methoxycarbonyl) -1,1' -dimethyl- [4,4 '-bipyridine ] -1,1' -diimine obtained in the step 4, and reacting to obtain 2,2 '-dicarboxyl-1, 1' -dimethyl- [4,4 '-bipyridine ] -1,1' -diimine;

。

7. use of an redox organic flow battery for energy storage according to any one of claims 1 to 6, wherein the use comprises: as an emergency back-up power supply, peak load regulated stationary storage for intermediate storage of discontinuous, unstable electrical energy, including intermediate storage of electrical energy of photovoltaic, wind, biomass, tidal or marine power plants, and for the field of electrical movement, including storage in land, air and water vehicles.