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CN-122000280-A - Electrode, preparation method thereof and lithium extraction method

CN122000280ACN 122000280 ACN122000280 ACN 122000280ACN-122000280-A

Abstract

The application relates to the technical field of electrochemistry, in particular to an electrode, a preparation method thereof and a lithium extraction method. The preparation method of the electrode comprises the following steps of calcining lithium manganate and terbium salt to obtain a first active substance, wherein the first active substance is LiMn 2‑X Tb X O 4 , X is more than or equal to 0.005 and less than or equal to 0.02, stirring the first active substance, a conductive agent, a binder and a solvent to obtain electrode slurry, covering the electrode slurry on a graphite sheet and drying to obtain a pre-electrode, and applying voltage to the first working electrode in a lithium removal three-electrode system by taking the pre-electrode as a first working electrode to enable lithium ions in the first active substance to be removed to form a second active substance with lithium vacancies, so that the electrode is obtained. The method provided by the embodiment of the application has the advantages of strong process controllability and simplicity, and the obtained second active material in the electrode has better cycle stability and selectivity to Li + .

Inventors

  • FU JIANJIE
  • TAN SIPING
  • HUANG YING
  • JI GENLIANG
  • LI JUNJUN
  • JIANG GUIBIN

Assignees

  • 国科大杭州高等研究院

Dates

Publication Date
20260508
Application Date
20260409

Claims (11)

  1. 1. A method of preparing an electrode comprising the steps of: calcining lithium manganate and terbium salt to obtain a first active substance, wherein the first active substance is LiMn 2- X Tb X O 4 , and X is more than or equal to 0.005 and less than or equal to 0.02; stirring the first active material, the conductive agent, the binder and the solvent to obtain electrode slurry; covering the electrode slurry on a graphite sheet and drying to obtain a pre-electrode; In the lithium removal three-electrode system, the pre-electrode is used as a first working electrode, and voltage is applied to the first working electrode so as to remove lithium ions in the first active material to form a second active material with lithium vacancies, thereby obtaining the electrode.
  2. 2. The preparation method according to claim 1, wherein the mass ratio of lithium manganate to terbium salt is 1:0.013-0.052; The mass ratio of the first active substance to the conductive agent to the binder to the solvent is 8:0.5-1.5:0.5-2.0:35-50; the terbium salt comprises at least one of terbium nitrate, terbium oxide and terbium acetate; The conductive agent comprises at least one of carbon black, carbon nanotubes and graphene; the solvent comprises N-methylpyrrolidone.
  3. 3. The method of claim 1, wherein the calcination temperature is 600 ℃ to 1000 ℃; The stirring time is 12-20 h, and the stirring speed is 600-1000 rpm.
  4. 4. The method of claim 1, wherein the means of covering comprises coating; the areal density of the pre-electrode was 0.5mg/cm 2 -2.7mg/cm 2 .
  5. 5. The method according to claim 1, wherein the drying is performed under vacuum, the temperature of the drying is 65 ℃ to 110 ℃, and the time of the drying is 8h to 14h.
  6. 6. The method of claim 1, wherein in the delithiated three electrode system, the first reference electrode comprises a silver electrode and/or a silver chloride electrode; The first pair of electrodes comprises silver flake electrodes; the electrolyte comprises a lithium salt solution with the concentration of 0.05mol/L to 1mol/L, and the lithium salt comprises at least one of lithium chloride, lithium sulfate, lithium nitrate and lithium acetate.
  7. 7. The method according to claim 1 or 6, wherein the voltage is 0.6V to 1V, and the time for applying the voltage is 1h to 3h.
  8. 8. An electrode obtained by the method of any one of claims 1 to 7.
  9. 9. The lithium extraction method is characterized by comprising the following steps of: Placing the electrode of claim 8 in a lithium-containing solution; In the lithium extraction three-electrode system, the electrode is taken as a second working electrode, a reduction potential is applied to the electrode, so that lithium intercalation is carried out on a second active material, and a lithium intercalation electrode is obtained.
  10. 10. The lithium extraction method according to claim 9, further comprising: In a desorption three-electrode system, an oxidation potential is applied to the lithium intercalation electrode to deintercalate lithium in the lithium intercalation electrode.
  11. 11. The method according to claim 9 or 10, wherein the lithium-containing solution comprises a lithium slag leachate, salt lake brine or lithium-containing wastewater, and the concentration of Li + in the lithium-containing solution is 10mg/L to 200mg/L, and the pH is 2.0 to 11.0.

Description

Electrode, preparation method thereof and lithium extraction method Technical Field The application relates to the technical field of electrochemistry, in particular to an electrode, a preparation method thereof and a lithium extraction method. Background Lithium is used as a core material of new energy automobiles and energy storage systems, and the demand of the lithium is rapidly increased year by year. The lithium resources in China are rich, but the lithium resources mainly exist in the form of salt lake brine and ores. In the lithium ore processing process, a large amount of lithium-containing waste residues are generated, the concentration of lithium in the leaching solution is low, and the leaching solution contains high-concentration Na +、K+、Mg2+、Ca2+ and other impurity ions, so that the traditional chemical precipitation method is difficult to realize high-selectivity lithium extraction. It should be noted that the foregoing is not necessarily prior art, and is not intended to limit the scope of the present application. Disclosure of Invention The embodiment of the application provides an electrode, a preparation method thereof and a lithium extraction method, which are used for solving or relieving one or more technical problems. In a first aspect of an embodiment of the present application, there is provided a method for manufacturing an electrode, including the steps of: Calcining lithium manganate and terbium salt to obtain a first active substance, wherein the first active substance is LiMn 2-xTbXO4, and X is more than or equal to 0.005 and less than or equal to 0.02; stirring the first active material, the conductive agent, the binder and the solvent to obtain electrode slurry; covering the electrode slurry on a graphite sheet and drying to obtain a pre-electrode; In the lithium removal three-electrode system, the pre-electrode is used as a first working electrode, and voltage is applied to the first working electrode so as to remove lithium ions in the first active material to form a second active material with lithium vacancies, thereby obtaining the electrode. The method provided by the embodiment of the application has strong process controllability and is simple, and the obtained electrode effectively inhibits the Jahn-Teller effect and manganese dissolution by doping terbium ions into the lithium manganate stable spinel structure, so that the cycling stability of a second active substance in the electrode and the selectivity of Li + are obviously improved. The electrode is particularly suitable for extracting lithium in complex systems such as lithium slag leaching liquid, salt lake brine and the like. The rare earth element is used for substituting part of Mn 3+ to generate lattice stress, limiting local distortion of Mn-O bonds, inhibiting C-axis elongation and structural collapse caused by Jahn-Teller effect, reducing the proportion of Mn 3+ on the surface after terbium element occupies octahedral sites of lithium manganate, reducing disproportionation reaction, namely reducing reaction 2Mn 3+→Mn2++Mn4+, further reducing Mn 2+ dissolution, further remarkably improving the cycle stability of a second active substance and the selectivity of Li +, and controlling the lithium removal amount by adjusting electrochemical parameters to form more lithium vacancy concentration, wherein uniformly distributed lithium vacancies can be used as channels for lithium ion transmission so as to facilitate extraction of lithium in a lithium-containing solution. In a word, the method is simpler in process, and the second active substance in the electrode has terbium elements which are uniformly doped and lithium vacancies which are uniformly distributed, so that the lithium extraction performance of the electrode in a complex system is improved, and the electrode can be used for extracting lithium in a complex system such as lithium slag leaching liquid, salt lake brine and the like. According to the embodiment of the application, the mass ratio of the lithium manganate to the terbium salt is 1:0.013-0.052, the mass ratio of the first active substance, the conductive agent, the binder and the solvent is 8:0.5-1.5:0.5-2.0:35-50, the terbium salt comprises at least one of terbium nitrate, terbium oxide and terbium acetate, the conductive agent comprises at least one of carbon black, carbon nano tubes and graphene, and the solvent comprises N-methylpyrrolidone. According to an embodiment of the application, the calcination temperature is 600-1000 ℃, the stirring time is 12-20 hours, and the stirring speed is 600-1000 rpm. According to an embodiment of the application, the covering mode comprises coating, and the surface density of the pre-electrode is 0.5mg/cm 2-2.7mg/cm2. According to an embodiment of the present application, the drying is performed under vacuum, the temperature of the drying is 65 ℃ to 110 ℃, and the time of the drying is 8h to 14h. According to the embodiment of the application, the li