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CN-121992221-A - Lithium corrosion-resistant negative electrode cover, preparation method thereof and lithium metal extraction device

CN121992221ACN 121992221 ACN121992221 ACN 121992221ACN-121992221-A

Abstract

The invention relates to a lithium corrosion-resistant negative electrode cover, a preparation method thereof and a lithium metal extraction device, wherein the preparation method comprises the following steps of (1) mixing a lithium source, an alkaline earth metal source and an alcohol solvent, and performing sanding and drying to obtain dried powder; and (2) mixing the dried powder with an alcohol solvent to obtain a mud-like mixture, and sintering to obtain the lithium corrosion-resistant negative electrode cover. The soft mud-shaped sealing material formed by adding the alcohol solvent is easier to operate and can be filled on the surface of glass more fully when being used for sealing, so that gaps generated by the microcosmic connecting force of dry powder are avoided, the sealing performance of a sealing material sintered body on the glass is improved, the shrinkage phenomenon of the sealing material in the sintering process is reduced or even avoided, and the sintered body forms a fully covered protective layer on the surface of the glass, thereby protecting the glass from corrosion of lithium metal on the glass in a high-temperature lithium-containing steam environment, and the formed protective layer has high sintering strength and good sealing performance.

Inventors

  • JIANG YIN
  • WEI XIANKUN
  • ZHAO LONGHUI

Assignees

  • 江苏新锂元科技有限公司

Dates

Publication Date
20260508
Application Date
20260205

Claims (10)

  1. 1. A method of preparing a lithium corrosion resistant negative electrode cap, the method comprising the steps of: (1) Mixing a lithium source, an alkaline earth metal source and an alcohol solvent, and performing sanding and drying to obtain dried powder; (2) Mixing the dried powder and an alcohol solvent to obtain a mud-like mixture, filling the mud-like mixture on the surface of the negative electrode cover glass to form a protective layer, and sintering to obtain the lithium corrosion-resistant negative electrode cover; the alkaline earth metal source of step (1) comprises a magnesium source and/or a calcium source.
  2. 2. The method of claim 1, wherein the molar ratio of the metal elements in the lithium source and the alkaline earth metal source in step (1) is 1:0.01-0.1, preferably 1:0.05-0.1.
  3. 3. The preparation method according to claim 1 or 2, wherein the mass ratio of the total mass of the lithium source and the alkaline earth metal source to the alcohol solvent in step (1) is 1:0.8-1.5.
  4. 4. A process according to any one of claims 1 to 3, wherein the mass ratio of the dry powder and the alcoholic solvent in step (2) is 1:0.2 to 0.3.
  5. 5. The method according to any one of claims 1 to 4, wherein the sintering temperature in step (2) is 690 ℃ to 720 ℃; Preferably, the sintering time is 3min-5min.
  6. 6. The method of any one of claims 1-5, wherein the lithium source of step (1) comprises any one or a combination of at least two of lithium carbonate, lithium nitrate or lithium hydroxide, preferably lithium carbonate; Preferably, the magnesium source comprises any one or a combination of at least two of magnesium oxide, magnesium hydroxide, magnesium nitrate or magnesium carbonate, preferably magnesium oxide; Preferably, the calcium source comprises any one or a combination of at least two of calcium oxide, calcium hydroxide, calcium nitrate or calcium carbonate, preferably calcium oxide; preferably, the alcoholic solvent comprises ethanol; Preferably, the purity of the alcohol solvent is more than or equal to 95%.
  7. 7. The method of any one of claims 1 to 6, wherein the rotational speed of the sanding in step (1) is 1500rpm to 2500rpm; preferably, the sanding of step (1) takes 1 to 3 hours; Preferably, the temperature of the drying is 60-90 ℃; Preferably, the drying time is 6-12 h.
  8. 8. The preparation method according to any one of claims 1 to 7, characterized in that the preparation method comprises the steps of: (1) Mixing a lithium source, an alkaline earth metal source and ethanol according to the mass ratio of the total mass of the lithium source and the alkaline earth metal source to the alcohol solvent of 1:0.8-1.5, sanding for 1-3 hours at 1500rpm-2500rpm to obtain powder with the average particle size of 0.1-30 mu m, and then drying for 6-12 hours at 60-90 ℃ and crushing into powder to obtain dried powder; the molar ratio of the metal elements in the lithium source and the alkaline earth metal source is 1:0.05-0.1; (2) Mixing the dried powder and ethanol according to the mass ratio of 1:0.2-0.3 to obtain a mud-like mixture, filling the mud-like mixture on the surface of the negative electrode cover glass to form a protective layer, and sintering at 690-720 ℃ for 3-5 min to obtain the lithium corrosion resistant negative electrode cover.
  9. 9. A lithium corrosion resistant negative electrode cap, characterized in that it is prepared according to the preparation method of any one of claims 1-8.
  10. 10. A lithium metal extraction device comprising the lithium corrosion resistant negative cap of claim 9.

Description

Lithium corrosion-resistant negative electrode cover, preparation method thereof and lithium metal extraction device Technical Field The invention relates to the technical field of lithium metal extraction, in particular to a lithium corrosion-resistant negative electrode cover, a preparation method thereof and a lithium metal extraction device. Background In the lithium metal extraction device, the insulating sealing glass of the negative electrode cover on the cathode bin mainly has the functions of insulation and sealing, but the cathode molten salt in the cathode bin volatilizes at high temperature, so that a small amount of metal lithium can be carried out, further, the sealing glass on the negative electrode cover of the cathode bin is corroded, the air tightness of the cathode bin is deteriorated, and the metal lithium generated by the cathode bin is oxidized. The traditional method aims at preserving lithium metal at normal temperature, such as paraffin, but the paraffin cannot protect the sealed glass after melting at high temperature. Therefore, there is a need to develop a material or method that is resistant to high temperatures and Li metal corrosion that prevents corrosion of the sealing glass on the cathode compartment negative cover. The prior art discloses an inorganic composite sealing material comprising inorganic carbonate and magnesium oxide, which can resist lithium corrosion, but the inventor discovers that the sealing material can shrink after the powdery inorganic composite sealing material is directly paved on the surface of glass and has poor adhesion effect with the glass, so that the sealing material cannot protect the sealing glass. Therefore, there is no suitable negative electrode cover protective layer material capable of adapting to high temperature environment and having good sealing performance and no shrinkage at high temperature in the prior art, and therefore, how to develop a negative electrode cover capable of resisting metal lithium corrosion, having good sealing performance and no shrinkage deformation at high temperature, which is applicable to metal lithium extraction equipment, and a preparation method thereof have become the problems to be solved in the present. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a lithium corrosion-resistant negative electrode cover, a preparation method thereof and a lithium metal extraction device, the mixture of lithium carbonate and magnesium oxide or calcium oxide is used for fusion sintering at high temperature on the surface of glass to form a fully covered protective layer, so that the corrosion of lithium-containing steam to the glass is prevented, the sintering strength of the protective layer is high, and the sealing performance is good. To achieve the purpose, the invention adopts the following technical scheme: in a first aspect, the present invention provides a method for preparing a lithium corrosion-resistant negative electrode cap, the method comprising the steps of: (1) Mixing a lithium source, an alkaline earth metal source and an alcohol solvent, and performing sanding and drying to obtain dried powder; (2) Mixing the dried powder with an alcohol solvent to obtain a mud-like mixture, filling the mud-like mixture on the surface of negative electrode cover glass to form a protective layer, and sintering to obtain the lithium corrosion-resistant negative electrode cover, wherein the alkaline earth metal source comprises a magnesium source and/or a calcium source in the step (1). According to the preparation method of the lithium corrosion-resistant negative electrode cover, compared with dry powder formed by mixing lithium carbonate and magnesium oxide, on one hand, the alcohol solvent is added, so that a soft mud-shaped sealing material can be formed, when the sealing material is used for glass sealing of a lithium metal extraction device, the operation is easier, the sealing material can be filled on the surface of glass more fully, gaps of dry powder due to microcosmic connecting force are avoided, and the sealing property of a sealing material sintered body to glass is improved; On the other hand, when the dry powder is used as the sealing material, the sealing material is easy to shrink upwards in the sintering process, is not adhered to the surface of the glass, and cannot form a fully-covered protective layer on the surface of the glass, so that the air tightness of the cathode bin is poor. The following preferred technical solutions are used as the present invention, but not as limitations on the technical solutions provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solutions. Preferably, the molar ratio of the metal elements in the lithium source and the alkaline earth metal source is 1:0.01-0.1, for example, 1:0.01, 1:0.02, 1: