Preparation method of large single crystal lithium ion battery nickel cobalt lithium manganate cathode material

Abstract

The invention relates to a preparation method of a single crystal lithium ion battery nickel cobalt lithium manganate cathode material. The method comprises the following steps of: (1) taking a small-grain crystal spherical NCM ternary precursor, a lithium salt and an A element-containing nano fluxing agent as raw materials, uniformly mixing the raw materials by adopting a dry-method high-speed mixing mode, and performing primary sintering under an oxygen-enriched atmosphere condition; (2) subjecting the sintered material to jaw breaking, roller pairing, crushing and sieving so as to obtain asingle-crystal once-sintered base material; and (3) mixing the primary sintering base material with a B element-containing nano coating agent, sintering again under an oxygen-enriched atmosphere condition, and then performing jaw breaking, roller pairing, crushing and sieving to obtain the large single crystal lithium nickel cobalt manganate cathode material. The cathode material prepared by the invention has the characteristics of the large particle size, the good dispersity, the moderate specific surface area, the high compaction density, the high voltage, the good high-temperature cycle performance and the like.

Description

Technical field [0001] The invention relates to the technical field of lithium ion power batteries for new energy vehicles, in particular to a method for preparing a large single crystal lithium ion battery nickel cobalt lithium manganate anode material. Background technique [0002] Since 2013, domestic new energy vehicle subsidies have maintained an overall downward trend; in 2018, financial subsidies for vehicles with a driving range of less than 150km will be suspended, while subsidies for vehicles with a high driving range will increase. This is a major part of the new subsidy policy in 2018. Features; however, in 2019, financial subsidies for vehicles with a driving range of less than 250km will cease to be issued, and the subsidy for models with a high driving range will decline rapidly on the basis of 2018. [0003] In 2019, the subsidy declined sharply, leading the market to put forward higher requirements for new energy vehicle power batteries, such as: high safety, high ...

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Problems solved by technology

[0006] However, the single crystal type ternary cathode material also has the following disadvantages, such as: (1) The capacity is low at the same voltage, because the sintering temperature of the single crystal type material is 20-30°C higher than that of the secondary ball material, The average particle size of the primary particle is about 2-3um; the average particle size of the secondary spherical primary particle is about 0.5-0.8um; therefore, the primary efficiency of the single crystal material will be significantly lower than that of the secondary spherical material, resulting in the same voltage Lower discharge capacity is low

[0007] (2) Large specific surface area: At present, small particle precursors are selected as raw materials for single crystal cathode materials, and the average particle size is about 3-5um; if the small particle precursors prepared by the continuous method are used, fine powder with a certain specific gravity will be mixed. This leads to a larger specific surface area, which in turn leads to a larger specific surface area of ​​the prepared single crystal cathode material, which requires higher requirements for the subsequent battery process.

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