Coated modified high-nickel positive electrode material as well as preparation method and application thereof

Abstract

The invention relates to a coated modified high-nickel positive electrode material as well as a preparation method and application thereof. The preparation method comprises the following steps: takingurea as a precipitant, adding the precipitant into a mixed solution of a dispersion liquid of the high-nickel positive electrode material and an aluminum source solution, heating at 50-55 DEG C, reacting uniformly, precipitating, and calcining to obtain the coated modified high-nickel positive electrode material. According to the method, urea is adopted as the precipitant, OH- is uniformly released in the heating reaction process, then uniform coating of aluminum oxide is achieved on the surface of the high-nickel positive electrode material, and the obtained coated and modified high-nickel positive electrode material has high thermal stability, long cycle life and good safety.

Description

technical field [0001] The invention belongs to the field of battery materials, and relates to a coated and modified high-nickel positive electrode material, a preparation method and application thereof. Background technique [0002] The requirement of high energy density for power batteries has promoted the development of high-nickel materials, lithium-rich manganese-based materials, lithium-sulfur batteries, lithium-air batteries, etc., but limited by the technical level, high-nickel materials are currently widely used. However, high-nickel materials often have disadvantages such as poor cycle performance, low thermal stability, and low safety. Because they are rich in nickel, they are prone to cation mixing. During the use of materials, the transition metal ions dissolve more seriously, which leads to the deterioration of the structural stability of the materials and triggers battery failure. A series of problems, such as increased internal resistance, excessive capacity ...

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Problems solved by technology

This method effectively reduces the residual lithium and the pH value, but due to physical mixing, it is difficult to ensure the uniformity of the coating; CN109950498A discloses a high-nickel positive electrode material with a uniform coating layer and its preparation method, the preparation The method comprises the following steps: (1) uniformly mixing the high-nickel positive electrode material with the lithium source and the nano-coating material in solid phase, and sieving to obtain the mixture; (2) placing the mixture in the step (1) in a sagger, and High-temperature sintering in a preheated muffle furnace under an oxygen atmosphere, cooling, crushing, and sieving to obtain a high-nickel cathode material with a uniform coating layer, which is coated by solid-phase physical mixing, and it is difficult to ensure uniform coating sex

CN109244407A discloses a method for coating a positive electrode material of nickel-cobalt lithium manganese oxide by blending magnesium oxide and aluminum oxide. The nickel-cobalt lithium manganate material is processed by blending magnesium oxide and aluminum oxide with a magnesium ion solution and an aluminum ion solution , making it possible to form a nickel-cobalt lithium manganese oxide material coated with magnesium oxide and aluminum oxide, which improves the cycle stability of the nickel-cobalt lithium manganese oxide material and improves the performance of the nickel-cobalt lithium manganate cathode material, but the coating process Alcohol solvents have been used in the production process, and the storage and use of alcohol raw materials are involved in large-scale production, during which there will be potential safety hazards

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