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CN-122000327-A - Preparation method of lithium iron chloride coated lithium-rich manganese-based composite positive electrode material and application of solid-state battery

CN122000327ACN 122000327 ACN122000327 ACN 122000327ACN-122000327-A

Abstract

The invention provides a preparation method of a lithium-rich manganese-based composite positive electrode material coated by lithium iron chloride and application of a solid-state battery, wherein a lithium iron chloride coating layer is obtained on the surface of the lithium-rich manganese-based positive electrode material in situ through spray drying, and compared with a common coating layer, the lithium iron chloride coating layer has the advantages of good compatibility of solid-state electrolyte, excellent conductivity, excellent ion conducting performance and the like, and is a novel halide positive electrode material developed for adapting to the solid-state electrolyte, so that interface incompatibility between a positive electrode and the solid-state electrolyte is reduced. In addition, the excellent conductivity of the lithium iron chloride can reduce the use of a positive electrode side conductive agent, reduce the diffusion tortuosity of ions and electrons and improve the diffusion coefficient. Meanwhile, the synthesis method is simple and effective, the cost is low, and the prepared composite positive electrode material can be used as an integrated all-solid-state positive electrode material and is suitable for large-scale production.

Inventors

  • HOU LIJUAN
  • LIU QI
  • CHEN RENJIE
  • CHEN XINYUAN
  • LI LI

Assignees

  • 北京理工大学

Dates

Publication Date
20260508
Application Date
20260205

Claims (9)

  1. 1. The lithium iron chloride coated composite lithium-rich manganese-based positive electrode material is characterized by being prepared by the following steps: (1) Adding lithium chloride, ferrous chloride, ferric chloride and an antioxidant into a proper amount of deionized water according to a proportion, and obtaining a uniform solution І through ultrasonic dispersion; (2) Adding the lithium-rich manganese-based positive electrode powder into the solution І, stirring to obtain a uniform mixed solution II, and spray-drying the mixed solution II to obtain powder; (3) Placing the obtained powder into a crucible, then placing the crucible into a heating device for high-temperature treatment, heating to 150-400 ℃ and calcining for 2-15 h, wherein the calcining atmosphere is nitrogen or argon, cooling after calcining, and obtaining the lithium-rich manganese-based anode material coated with lithium iron chloride in the crucible; The molar ratio of lithium chloride to ferrous chloride to ferric chloride is 13:9:3, the antioxidant accounts for 1% of the mass of the lithium iron chloride, the lithium iron chloride coating accounts for 2% -7% of the total mass of the positive electrode material, the lithium-rich manganese-based positive electrode powder is xLi 2 MnO 3 ·(1-x)LiMO 2 , and M is at least one of Mn, co and Ni, and x is more than or equal to 0 and less than or equal to 1.
  2. 2. The lithium iron chloride-coated composite lithium-rich manganese-based positive electrode material according to claim 1, wherein in the step (1), the antioxidant is ascorbic acid or citric acid, and is used for preventing ferrous iron oxidation in the synthesis process.
  3. 3. The lithium iron chloride coated composite lithium-rich manganese-based positive electrode material according to claim 1, wherein in the step (1), the ultrasonic intensity is 100-200 KHZ and the ultrasonic time is 0.5-2 h during ultrasonic dispersion.
  4. 4. The lithium iron chloride coated composite lithium-rich manganese-based positive electrode material according to claim 1, wherein in the step (2), the stirring temperature is room temperature, the rotating speed is 500-1500 rpm, the stirring time is 0.25-1 h, and the spray drying temperature is 150-250 ℃.
  5. 5. The lithium iron chloride coated composite lithium-rich manganese-based positive electrode material according to claim 1, wherein in the step (3), a heating device is a tube furnace, nitrogen or argon is introduced in the calcining process, and the air flow is 50-300 cfm.
  6. 6. The lithium iron chloride coated composite lithium-rich manganese-based positive electrode material according to claim 1, wherein the particle diameter of the lithium iron chloride coated composite lithium-rich manganese-based positive electrode material is 2-15 mu m, and the thickness of the lithium iron chloride coating layer is 5-100 nm.
  7. 7. The method for preparing the lithium iron chloride coated composite lithium-rich manganese-based positive electrode material and the application of the solid-state battery as claimed in any one of claims 1 to 6, wherein the lithium iron chloride coated composite lithium-rich manganese-based positive electrode material is applied to an all-solid-state lithium battery.
  8. 8. The use of a solid state battery of lithium iron chloride coated composite lithium-rich manganese based positive electrode material according to claim 7, wherein the solid state electrolyte of the all-solid state lithium battery comprises a halide solid state electrolyte layer and a sulfide solid state electrolyte layer.
  9. 9. The solid state battery application of a lithium iron chloride coated composite lithium-rich manganese-based positive electrode material according to claim 7, wherein the preparation method of the all-solid state lithium battery comprises the following steps: (1) Uniformly scattering halide solid electrolyte powder or sulfide solid electrolyte powder into a tabletting mold, and maintaining the pressure for 30-60 s under 300-500 MPa to enable the powder electrolyte to be pressed into tablets, wherein the mass of the solid electrolyte tablet is 100 mg, and the thickness is 500 mu m; (2) Uniformly scattering the lithium iron chloride coated composite lithium-rich manganese anode material on one side of a solid electrolyte sheet, and maintaining the pressure for 60-120 s under 300-500 MPa, wherein the thickness of the composite lithium-rich manganese anode material is 10 mg and is preferably 70 mu m after tabletting; (3) And adding a negative electrode material on one side of the sulfide solid electrolyte, wherein the negative electrode material is lithium metal, and the thickness of the pressed sheet is 30 mu m.

Description

Preparation method of lithium iron chloride coated lithium-rich manganese-based composite positive electrode material and application of solid-state battery Technical Field The invention relates to a preparation method of a lithium-rich manganese-based composite positive electrode material coated by lithium iron chloride and application of a solid-state battery, and belongs to the technical field of lithium ion batteries. Background Driven by the large-scale application of electric automobiles, the lithium ion battery realizes the rapid development in the past ten years, the energy density of the lithium ion battery is over 300 Wh/kg, and the cost is obviously reduced to about $100/kWh. The global battery usage of electric vehicles has reached 517.9 GWh, which has led to an industry with a scale of billions of dollars. However, lithium ion batteries based on liquid electrolytes have gradually approached their energy density limit and present certain safety concerns. In order to meet the increasing demands for high energy density, high safety and long life batteries, the academia and industry have actively focused on the development of next generation battery technologies in recent years, including all-solid-state batteries, lithium-sulfur batteries, lithium-air batteries, and the like. Among them, all-solid-state batteries are widely regarded as subversion technologies that promote the popularization of electric vehicles due to their remarkable advantages in terms of safety, energy density, power characteristics, temperature adaptability, electrode material selection, and the like. Automobile manufacturers are expected to expect that all-solid-state batteries will significantly promote the comprehensive competitiveness of electric automobiles in terms of endurance mileage, charging speed, cost control, integration efficiency, environmental suitability, and the like. Some conventional positive electrode materials (e.g., lithium cobaltate and nickel-rich oxide positive electrodes) have been successfully used in all-solid-state batteries, but such positive electrode materials are limited by their intrinsic capacity, which is mostly below 200 mAh/g. Unlike conventional anodes that rely solely on the redox reaction of transition metal ions to provide capacity, lithium-rich manganese-based layered oxide anodes are capable of providing additional capacity (> 250 mAh/g) by triggering the redox reaction of anionic oxygen, thereby breaking through the capacity bottleneck that is presented by conventional transition metal redox mechanisms. Therefore, the application of lithium-rich manganese-based positive electrodes to all-solid-state batteries has become an important research direction for improving the energy density of batteries. The prior related researches mainly apply a coating technology to modify the surface of the lithium-rich manganese-based material so as to improve the overall performance of the all-solid-state battery, but the prior methods mostly cannot achieve ideal effects and are difficult to expand production due to the reasons of poor uniformity of a coating layer, complex in-situ synthesis process, cost and the like. Disclosure of Invention In view of the above, the present invention aims to provide a preparation method of lithium-rich manganese-based composite positive electrode material coated with lithium iron chloride and a solid-state battery application. In order to achieve the above purpose, the technical scheme of the invention is as follows: The lithium-rich manganese-based composite anode material coated with lithium iron chloride is characterized by being prepared by the following steps: (1) Adding lithium chloride, ferrous chloride, ferric chloride and an antioxidant into a proper amount of deionized water according to a proportion, and obtaining a uniform solution І through ultrasonic dispersion; (2) Adding the lithium-rich manganese-based positive electrode powder into the solution І, stirring to obtain a uniform mixed solution II, and spray-drying the mixed solution II to obtain powder; (3) Placing the obtained powder into a crucible, then placing the crucible into a heating device for high-temperature treatment, heating to 150-400 ℃ and calcining for 2-15 h, wherein the calcining atmosphere is nitrogen or argon, cooling after calcining, and obtaining the lithium-rich manganese-based anode material coated with lithium iron chloride in the crucible; The molar ratio of the lithium chloride to the ferrous chloride to the ferric chloride is 13:9:3, the antioxidant accounts for 1% of the mass of the lithium iron chloride, the lithium iron chloride coating accounts for 2% -7% of the total mass of the positive electrode material, the lithium-rich manganese-based positive electrode powder is xLi 2MnO3·(1-x)LiMO2, and M is at least one of Mn, co and Ni, and x is more than or equal to 0 and less than or equal to 1. Preferably, in step (1), the antioxidant is ascorbic acid or citric acid, and