A glassy coated positive electrode material and preparation method thereof

Abstract

A glassy coated positive electrode material, comprising a positive electrode material substrate and a glassy substance Li coated on the surface of the positive electrode material substrate 3‑3f al f BO 3 , where 0<f<1. Preparation method of the present invention: according to Li 3‑3f al f BO 3 Proportion Weigh the raw materials, and first dissolve the weighed Al source in ethanol solvent, then add the B source, stir to obtain a coating solution; then add the Li source to the coating solution, and stir to obtain a viscous glassy gel coating material; adding the glassy colloidal coating material into the positive electrode material matrix to be coated, stirring, drying, sieving, sintering, crushing, and sieving to obtain the glassy coated positive electrode material. The coating used in the present invention is a dense glassy substance with strong adhesion. After coating, it can fill the voids and holes on the surface of the positive electrode material particles, effectively reduce the specific surface area, reduce the side reaction between the electrolyte and the positive electrode material, and prevent Structural collapse improves long-cycle performance.

Description

technical field [0001] The invention belongs to the field of lithium ion battery materials, and in particular relates to a glass-state coated positive electrode material and a preparation method thereof. Background technique [0002] In recent years, with the strong support of domestic and foreign governments, new energy electric vehicles have attracted more and more attention and developed rapidly. As the core technology of electric vehicles, the research of power batteries has become the key. Lithium-ion batteries are recognized as the most promising power batteries for electric vehicles due to their advantages such as high specific capacity, long cycle life, low self-discharge rate, no memory effect, and environmental friendliness. The performance of the power battery mainly depends on the cathode material. [0003] The most basic requirement for an ideal positive electrode material for power lithium batteries is to have a long cycle life. At present, it is required to ...

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Problems solved by technology

At present, in order to solve the problems of long cycle life and safety performance of positive electrode materials, inorganic electrochemically active metal oxides are usually doped or coated, and doped metal elements replace the main metal elements of positive electrode materials to enhance the bond energy, but this coating The material prevents the positive electrode material particles from directly detecting the electrolyte, prevents the dissolution of the main elements, shortens the cycle life, and affects safety performance due to lattice collapse; moreover, the coating with metal oxides is generally coated with particles, and it is difficult to form a uniform and dense coating. The coating still has partial contact with the electrolyte, which cannot block the erosion of the electrolyte well

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