Lithium iron manganese phosphate coated single crystal quaternary positive electrode material and preparation method thereof

Abstract

The invention discloses a lithium iron manganese phosphate coated single crystal quaternary positive electrode material, wherein the molecular formula is LiNixCoyMnzM1-x-y-zO2@(LiMnaFe1-aPO4), x is more than or equal to 0.50 and less than or equal to 0.90, y is more than or equal to 0.05 and less than or equal to 0.20, z is more than or equal to 0.05 and less than or equal to 0.30, 1-x-y-z is more than or equal to 0 and less than or equal to 0.03, a is more than or equal to 0.5 and less than or equal to 1, and the lithium iron manganese phosphate coated single crystal quaternary positive electrode material is composed of a single crystal quaternary positive electrode material and a lithium iron manganese phosphate nano coating layer coating the surface of the single crystal quaternary positive electrode material. The preparation method comprises the following steps: mixing a lithium source and a precursor to prepare a single crystal quaternary positive electrode material, mixing the single crystal quaternary positive electrode material with a coating agent lithium iron manganese phosphate, calcining, cooling, and sieving to obtain the lithium iron manganese phosphate coated single crystal quaternary positive electrode material. According to the invention, the obtained lithium iron manganese phosphate coated single crystal quaternary positive electrode material product is fine in particle, uniform in coating distribution and excellent in electrochemical performance, and the preparation method is simple to operate and easy for industrial production.

Description

technical field [0001] The present invention relates to a single crystal quaternary positive electrode material, in particular to a single crystal quaternary positive electrode material coated with iron manganese lithium phosphate, and also relates to a preparation method of the above-mentioned single crystal quaternary positive electrode material covered with iron manganese lithium phosphate. Background technique [0002] Lithium batteries are widely used in various fields such as electronic products, automobiles, and aerospace due to their high energy density and good cycle performance. As people have higher and higher requirements on the environmental protection, battery life, and life of lithium-ion batteries, the design and optimization of batteries are becoming more and more important. As the core of lithium-ion batteries, the quality of the cathode material directly determines the performance of the battery. Multi-component cathode materials have become an important ...

AI Technical Summary

Problems solved by technology

At present, the commonly used quaternary cathode materials are coated with conventional coating agents. It is difficult to form a complete and dense coating layer due to phase doping or mismatching of the discharge platform. The electrolyte and the HF in the electrolyte can contact the untreated The reaction occurs after the coating position, and it is easy to fall off after long-term circulation. It cannot protect the main material in the later stage of the cycle. The coated metal oxides are all non-electrochemically active materials, and the ion conductivity is very poor.

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