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CN-118005142-B - Electrochemical desalination method utilizing retired lithium ion battery anode and application thereof

CN118005142BCN 118005142 BCN118005142 BCN 118005142BCN-118005142-B

Abstract

The invention discloses an electrochemical desalting method of a retired lithium ion battery, and relates to the technical field of resource environments. The electrochemical desalting method comprises the steps of mixing retired lithium ion battery anode powder in a modified solution, reacting, filtering a solid-liquid suspension system after the reaction to obtain a lithium-containing filtrate and a precipitate, washing and drying the precipitate to obtain an electrochemical desalting electrode material, mixing the obtained electrochemical desalting electrode material, a conductive agent and a binder in an organic solvent, then dropwise adding the mixture onto carbon cloth, drying to obtain an electrochemical desalting electrode, placing the obtained electrochemical desalting electrode in a double-electrode desalting system for desalting, wherein a saturated sodium carbonate solution is added into the lithium-containing filtrate, recovering lithium through a precipitation method, and the modified solution comprises a ferricyanide solution and/or a ferrocyanide solution, wherein the modified solution is an acidic solution.

Inventors

  • ZENG QIANG
  • WANG RUIGANG

Assignees

  • 广东省科学院生态环境与土壤研究所

Dates

Publication Date
20260512
Application Date
20240115

Claims (9)

  1. 1. An electrochemical desalination method utilizing a retired lithium ion battery anode, comprising the following steps: s1, preparing a modified solution, mixing the anode powder of the retired lithium ion battery in the modified solution, reacting, filtering a solid-liquid suspension system after the reaction to obtain a lithium-containing filtrate and a precipitate, and purifying the precipitate to obtain an electrochemical desalting electrode material; S2, mixing the electrochemical desalting electrode material obtained in the step S1 with a conductive agent and a binder in an organic solvent, dripping the mixture onto carbon cloth, and drying the mixture to obtain an electrochemical desalting electrode; S3, placing the electrochemical desalting electrode obtained in the step S2 in a double-electrode desalting system to perform desalting; Wherein, adding saturated sodium carbonate solution into the lithium-containing filtrate obtained in the step S1, and recovering lithium by a precipitation method; The modification solution in the step S1 comprises ferricyanide solution and/or ferrocyanide solution, wherein the modification solution is acid solution; In the step S2, the mass ratio of the electrochemical desalting electrode material to the conductive agent to the binder is (5-9) 1:1; in the desalting process of the step S3, the current density is 20-160 mA/g; The concentration of sodium chloride in the salt solution desalted in the step S3 is 500-1000 mg/L; the pH value of the desalted salt solution in the step S3 is 4-12; The positive electrode powder of the retired lithium ion battery in the step S1 is LiNi 0.8 Co 0.1 Mn 0.1 O 2 、LiNi 0.6 Co 0.2 Mn 0.2 O 2 、LiNi 0.5 Co 0.2 Mn 0.3 O 2 or LiNi 0.33 Co 0.33 Mn 0.33 O 2 .
  2. 2. The electrochemical desalination method according to claim 1, wherein the modifying solution in the step S1 is one or more of sodium ferricyanide, potassium ferricyanide, sodium ferrocyanide, potassium ferrocyanide; And/or, the modification solution in the step S1 contains sulfuric acid.
  3. 3. The electrochemical desalination method according to claim 1 or 2, characterized in that the concentration of the modifying solution of step S1 is 0.2-6 mol/L; And/or the concentration of sulfuric acid in the modified solution in the step S1 is 0.1-10 mol/L; and/or the volume mass ratio of the modified solution to the retired lithium ion battery anode powder in the step S1 is (1-100) mL/1 g.
  4. 4. The electrochemical desalination method according to claim 1, wherein the mixing in the step S1 is performed under stirring conditions at a stirring speed of 100 to 1000rpm; And/or the reaction temperature in the step S1 is 5-95 ℃ and the reaction time is 0.5-12 h.
  5. 5. The electrochemical desalination method of claim 1, wherein the conductive agent in step S2 comprises conductive carbon black; and/or the binder in the step S2 comprises polyvinylidene fluoride; And/or the organic solvent in the step S2 comprises at least one of dimethylacetamide, dimethylformamide and ethanol.
  6. 6. The electrochemical desalination method according to claim 1 or 5, wherein the mass-to-volume ratio of the electrochemical desalination electrode material to the organic solvent in the step S2 is (1-20) mg (5-20) mL.
  7. 7. The electrochemical desalination method according to claim 1, wherein the drying temperature in step S2 is 60-90 ℃; and/or the drying time in the step S2 is 1-12 h; and/or mixing in the step S2 is performed under stirring, and the stirring speed is 200-1500 rpm.
  8. 8. The electrochemical desalination method of claim 1, wherein the addition amount of the saturated sodium carbonate solution is 10-40% of the volume of the lithium-containing filtrate; and/or the reaction temperature of the precipitation method is 80-100 ℃, and the reaction time is 0.5-6 h; and/or the reaction of the precipitation method is carried out under stirring, and the stirring speed is 50-500 rpm.
  9. 9. Use of the electrochemical desalination method of any one of claims 1-8 in salt water desalination or wastewater recovery.

Description

Electrochemical desalination method utilizing retired lithium ion battery anode and application thereof Technical Field The invention relates to the technical field of resource environment, in particular to an electrochemical desalting method utilizing an anode of a retired lithium ion battery and application thereof. Background Desalination of salt water or recovery of waste water is an important way to address the shortage of fresh water resources. Currently, the main method for desalting salt water is electrochemical desalination, and the electrochemical method mainly comprises two modes of Capacitive Deionization (CDI) and Battery Deionization (BDI). Among them, battery Deionization (BDI) relies on the phase regulation mediated by the redox process between anions/cations in salt water and electrode active materials to achieve ion removal, thus having higher selectivity and relatively lower energy consumption, but currently there is still a lack of active reactive materials for battery deionization process with relatively lower cost, limiting the scale application of the technology. On the other hand, with the increase of the demand of new energy in society, the yield of retired lithium ion batteries is gradually increased, and if the retired lithium ion batteries are improperly disposed, the waste of resources is caused, and the retired lithium ion batteries are easy to cause great harm to the environment. Therefore, the recycling or comprehensive utilization of the retired lithium ion battery is a necessary way for the development of environment-friendly society. In the existing fire method or wet process for recycling the retired lithium ion batteries, the defects of high acid/alkali consumption, long process flow and the like often exist, a large amount of high-salt wastewater is usually generated, and the complete disposal of the high-salt wastewater is a problem which needs to be solved. Therefore, how to prepare electrode materials with high reactivity based on retired lithium ion battery resources for desalting treatment of high-salt wastewater so as to realize green closed-loop recovery in retired lithium ion battery recovery industry is a problem to be solved currently. Disclosure of Invention The present invention aims to solve at least one of the above technical problems in the prior art. Therefore, the invention aims to provide an electrochemical desalting method utilizing the anode of the retired lithium ion battery, wherein the anode material of the retired lithium ion battery is reacted with (ferrous) ferricyanide to obtain an electrochemical desalting electrode material, and the electrochemical desalting electrode material is further used in electrochemical desalting to realize the combination of the recycling of the retired lithium ion battery and the desalting of salt water or the recycling of waste water. In a second aspect the invention provides the use of an electrochemical desalination method. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: the first aspect of the invention provides an electrochemical desalination method using a retired lithium ion battery anode, comprising the steps of: S1, preparing a modified solution, mixing the anode powder of the retired lithium ion battery in the modified solution, reacting, filtering a solid-liquid suspension system after the reaction to obtain a lithium-containing filtrate and a precipitate, and purifying the precipitate to obtain an electrochemical desalting electrode material; S2, mixing the electrochemical desalting electrode material obtained in the step S1 with a conductive agent and a binder in an organic solvent, dripping the mixture onto carbon cloth, and drying the mixture to obtain an electrochemical desalting electrode; S3, placing the electrochemical desalting electrode obtained in the step S2 in a double-electrode desalting system to perform desalting; Wherein, adding saturated sodium carbonate solution into the lithium-containing filtrate obtained in the step S1, and recovering lithium by a precipitation method; The modification solution in the step S1 comprises ferricyanide solution and/or ferrocyanide solution, wherein the modification solution is an acidic solution. The basic principle of the invention is that transition metal in the positive electrode of the retired ion battery reacts with ferricyanide under the acid condition to be converted into a Prussian blue-like basic structure, star precipitation is carried out, and meanwhile, lithium ions are remained in the lithium-containing filtrate. The Prussian blue-like basic structure can be combined with sodium ions migrating in the desalted salt solution under electric drive and undergo oxidation-reduction reaction, thereby realizing the reduction of the salt content in the solution. Taking the reaction process of potassium ferrocyanide and lithium cobaltate as an example, the specific chemical reaction process is as fol