Search

CN-121394480-B - Water system full-chromium flow battery electrolyte, preparation method and battery comprising same

CN121394480BCN 121394480 BCN121394480 BCN 121394480BCN-121394480-B

Abstract

The invention discloses an electrolyte of a water system full-chromium flow battery, a preparation method and a battery containing the same, belonging to the technical field of electrochemical energy storage, the positive and negative active substances of the water system full-chromium flow battery provided by the invention are chromium elements, the soluble compound containing cations or anions in the form of oxygen acid radicals is used as the additive, so that the capacity attenuation problem caused by cross contamination of different metal ions is radically solved, and the method has the advantages of low theoretical cost, long life cycle and high energy density. By introducing the additive, the problems of slow reaction kinetics of chromium ions, serious hydrogen evolution side reaction, poor chemical stability and the like are solved, so that the water system full-chromium flow battery system can realize stable operation, and a new solution is provided for large-scale energy storage.

Inventors

  • JIANG HAORAN
  • WANG XIAOYI

Assignees

  • 天津大学

Dates

Publication Date
20260508
Application Date
20251225

Claims (8)

  1. 1. The aqueous full-chromium flow battery electrolyte is characterized by comprising a positive electrode electrolyte and a negative electrode electrolyte, wherein the positive electrode electrolyte and the negative electrode electrolyte independently comprise active substances, additives, supporting electrolytes and solvents; the active substances are soluble trivalent chromium salts, and the active substances of the positive and negative electrolyte are soluble trivalent chromium salts; the supporting electrolyte is selected from one of soluble compounds containing anions such as sulfate, chloride, nitrate, bromide, iodide, perchlorate or methanesulfonate; The additive is selected from at least one of ：Bi 3+ 、Cu 2+ 、Pb 2+ 、In 3+ 、Al 3+ 、Fe 3+ 、Co 2+ 、Ni 2+ 、Sn 2+ 、Sb 3+ 、Ru 3+ 、Mg 2+ 、Mn 2+ 、Ag + 、Ce 3+ 、Cd 2+ 、Ga 3+ 、Ti 3+ 、Pd 2+ 、Tl + 、Pt 4+ 、Nd 3+ 、Ba 2+ 、Ca 2+ 、Au 3+ 、SeO 3 2- 、TeO 3 2- 、MoO 3 2- 、WO 3 2- 、[PMo 12 O 40 ] 3- 、[PW 12 O 40 ] 3- and [ SiW 12 O 40 ] 3- ] soluble compounds containing the following cations or anions in the form of oxyacids; The solvent is water; In the positive electrode electrolyte, the concentration of the soluble trivalent chromium salt is 0.2 mol/L-2 mol/L, the concentration of the additive is 0.05 mol/L-0.5 mol/L, and the concentration of hydrogen ions in the supporting electrolyte is 1 mol/L-3 mol/L; In the negative electrode electrolyte, the concentration of the soluble trivalent chromium salt is 0.2 mol/L-2 mol/L, the concentration of the additive is 0.05 mol/L-0.5 mol/L, and the concentration of the hydrogen ions in the supporting electrolyte is 1 mol/L-3 mol/L.
  2. 2. The aqueous all-chromium flow battery electrolyte according to claim 1, wherein in the positive electrode electrolyte, the concentration of the soluble trivalent chromium salt is 0.5mol/L to 1.5mol/L, the concentration of the additive is 0.1mol/L to 0.2mol/L, and the concentration of the hydrogen ions in the supporting electrolyte is 1mol/L to 2mol/L; And/or in the negative electrode electrolyte, the concentration of the soluble trivalent chromium salt is 0.5 mol/L-1.5 mol/L, the concentration of the additive is 0.1 mol/L-0.2 mol/L, and the concentration of the hydrogen ions in the supporting electrolyte is 1 mol/L-2 mol/L.
  3. 3. A preparation method of the aqueous full-chromium flow battery electrolyte according to any one of claims 1-2 is characterized by comprising the following steps of dissolving active substances and additives in a solvent, adding a supporting electrolyte, and uniformly stirring to obtain the positive electrolyte; The preparation method of the negative electrode electrolyte comprises the following steps of dissolving active substances and additives in a solvent, adding a supporting electrolyte, and uniformly stirring to obtain the negative electrode electrolyte.
  4. 4. An aqueous all-chromium flow battery characterized in that the electrolyte is the aqueous all-chromium flow battery electrolyte according to any one of claims 1-2.
  5. 5. The aqueous all-chromium flow battery according to claim 4, comprising a negative electrode, a positive electrode, a negative electrolyte reservoir, a positive electrolyte reservoir, a membrane, a negative peristaltic pump, and a positive peristaltic pump; The negative electrode electrolyte liquid storage tank is used for storing negative electrode electrolyte, and the positive electrode electrolyte liquid storage tank is used for storing positive electrode electrolyte; The cathode peristaltic pump is used for pumping cathode electrolyte to the cathode electrode, and the anode peristaltic pump is used for pumping anode electrolyte to the anode electrode; The separator is used for separating the negative electrode electrolyte and the positive electrode electrolyte.
  6. 6. The aqueous all-chromium flow battery according to claim 5, wherein the negative electrode and the positive electrode are both porous carbon materials; and/or the membrane is a polymer membrane with ion selective permeability.
  7. 7. The aqueous all-chromium flow battery according to claim 6 wherein the porous carbon material is selected from graphite felt, carbon cloth or carbon paper.
  8. 8. The aqueous all-chromium flow battery according to claim 6, wherein the polymer membrane having ion selective permeability is selected from the group consisting of a perfluorosulfonic acid proton exchange membrane, a sulfonated polyetheretherketone membrane, a polyethylene porous membrane and an anion exchange membrane.

Description

Water system full-chromium flow battery electrolyte, preparation method and battery comprising same Technical Field The invention belongs to the technical field of electrochemical energy storage, and particularly relates to a water system full-chromium flow battery electrolyte, a preparation method and a battery containing the same. Background With the acceleration of global energy transformation, the grid-connected scale of renewable energy sources such as wind energy, solar energy and the like is increasingly enlarged. However, the intermittent and fluctuating nature of the grid poses a significant challenge for stable operation of the grid. Therefore, developing efficient and reliable large-scale long-term energy storage technology has become a key for guaranteeing energy safety. Among the numerous energy storage technologies, flow batteries are considered as one of the most promising large-scale energy storage technologies due to their unique advantages of power and capacity decoupling, long cycle life, high safety, etc. The vanadium redox flow battery technology is the most mature, and the vanadium element is used as an active material, so that the problem of cross contamination of different metal ions is effectively avoided. However, the development of all-vanadium redox flow battery systems is deeply limited by the high price of vanadium resources and the fluctuation of supply. To reduce the cost, bimetallic systems such as iron-chromium flow batteries have been proposed that employ iron and chromium as active materials in a rich resource. However, the system has a new technical problem of cross contamination due to the difference of the positive and negative electrolytes, so that the battery capacity is continuously attenuated, and the complexity of system control is increased. The chromium element has abundant reserves and low price, and has been studied for many years as a negative electrode active material in the iron-chromium flow battery, but until now, no research or technical scheme has been found to successfully propose or construct a full-chromium flow battery system with both positive and negative electrode active materials adopting chromium element. This is mainly because the realization of the system faces the problems that the reaction kinetics of Cr (VI)/Cr (III) couple is slow, the chemical stability of hexavalent chromium in acidic aqueous solution is poor, side reactions or decomposition are easy to occur, and the like. Therefore, a novel all-chromium flow battery system based on a single chromium element is developed, and the novel all-chromium flow battery system has great scientific value and application prospect. Disclosure of Invention In order to solve the technical problems, the invention provides an aqueous full-chromium flow battery electrolyte, a preparation method and a battery comprising the aqueous full-chromium flow battery electrolyte. The full-chromium system fundamentally avoids the capacity attenuation problem caused by cross contamination of different metal ions, and has the advantages of low cost, long life cycle and high energy density. Meanwhile, the invention solves the problems of slow reaction kinetics of chromium ions, serious hydrogen evolution side reaction, poor chemical stability and the like by introducing the additive, and the long-term chemical stability of the electrolyte and the cycle life of the battery are obviously improved by introducing the additive. In order to achieve the above purpose, the present invention provides the following technical solutions: The invention provides an aqueous full-chromium flow battery electrolyte which consists of an anode electrolyte and a cathode electrolyte, wherein the anode electrolyte and the cathode electrolyte independently consist of active substances, additives, supporting electrolytes and solvents; the active substances are soluble trivalent chromium salts, and the active substances of the positive and negative electrolyte are soluble trivalent chromium salts; the supporting electrolyte is selected from one of soluble compounds containing anions such as sulfate, chloride, nitrate, bromide, iodide, perchlorate or methanesulfonate; the additive is selected from at least one of ：Bi3+、Cu2+、Pb2+、In3+、Al3+、Fe3+、Co2+、Ni2+、Sn2+、Sb3+、Ru3+、Mg2+、Mn2+、Ag+、Ce3+、Cd2+、Ga3+、Ti3+、Pd2+、Ge4+、Tl+、Pt4+、Nd3+、Ba2+、Ca2+、Au3+、SeO32-、TeO32-、MoO32-、WO32-、[PMo12O40]3-、[PW12O40]3- and [ SiW 12O40]3- ] soluble compounds containing the following cations or anions in the form of oxyacids; The solvent is water. The anode reaction of the existing iron-chromium flow battery is Fe 3++e-↔Fe2+, and the anode reaction of the water system full-chromium flow battery is Cr 2O72-+6e-+14H+↔2Cr3++7H2 O, which is different from the related technology of the iron-chromium flow battery. The full chromium system of the invention is not a simple improvement of the existing iron-chromium system, but is a brand new system constructed from a completely dif