Preparation method of ternary material coated with orthosilicate positive electrode material

Abstract

The invention discloses a preparation method of a ternary material coated with an orthosilicate positive electrode material. The chemical composition general formula of the orthosilicate positive electrode material is Li2MSiO4 (M is at least one of Fe, Mn, Co and Ni). The coating content of the orthosilicate positive electrode material accounts for 0.01-10% of the mass fraction of the positive electrode material, and the thickness of a coating layer is 10-1000 nm. The method comprises the following steps: measuring the content and components of residual lithium on the surface of the ternary material, adding a nanoscale lithium source, a corresponding metal M source, a silicon source and the like according to the coating content and the molecular molar ratio, carrying out fluidized mixing,tabletting, sintering, pulverizing, and screening to obtain the ternary positive electrode material coated with the orthosilicate positive electrode material. The method is a pure dry process, the preparation method is simple and easy to implement, the overcharge resistance and thermal stability of the ternary material can be improved while the residual lithium on the surface is reduced, the electrical property of the material is improved, and the method has a certain industrial application prospect.

Description

technical field [0001] The invention belongs to the technical field of lithium-ion battery cathode materials and preparation thereof, and in particular relates to a preparation method for orthosilicate-based cathode materials dry-coated ternary materials. Background technique [0002] With the rapid development of 3C digital electronic products, electric tools and electric vehicles, the requirements for batteries are getting higher and higher, and among the key technologies restricting the development of batteries, cathode material technology is a key link. In the actual sintering production of positive electrode materials, especially medium-high nickel ternary materials, due to the volatilization of lithium, in order to obtain a better crystal structure, an excessive amount of lithium source is often added, so that residual lithium often exists on the surface of the product. Residual lithium refers to lithium oxides, hydroxides, and carbonates on the surface of ternary mate...

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Problems solved by technology

The patent only quantifies the amount of coating, and other key indicators are not mentioned, and the mixing method has a great influence on the coating effect. Conventional methods or mixing effects are poor, and coating uniformity is difficult to guarantee

Or the cost is high, which limits the actual performance of the cladding material

Moreover, positive electrode materials, especially high-nickel products, in order to prepare products with excellent performance, often need to be sintered with an excessive amount of lithium source before sintering. This synthesis route often leads to excessive residual lithium on the surface, and the general residual content is 0.5~ 5%, which will affect the subsequent battery manufacturing process. Joint treatment is rarely considered in the treatment of residual lithium on the surface, and the input amount and input method of additives are also relatively extensive.

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