A preparation method of an alumina-coated manganese-doped lithium iron phosphate cathode material

Abstract

The invention relates to the technical field of cathode materials for lithium ion batteries, in particular to a preparation method of an alumina-coated manganese-doped lithium iron phosphate cathode material, which comprises the following steps in turn: (1) ball milling a phosphorus source, an iron source, a lithium source carbon source and a reducing agent to obtain a manganese-doped lithium ironphosphate precursor; 2, adding a manganese source into a manganese-doped lithium iron phosphate precursor solution, successively dropping ammonia water, hydrothermal reacting, drying, calcining, andcooling to obtain that manganese-doped lithium iron phosphate material; 3) uniformly stirring that manganese doped lithium iron phosphate material and the organic solvent, adding aluminum salt solution in the stirring, and successively stirring, pumping, filter, drying, roasting, cooling to obtain an alumina coated manganese doped lithium iron phosphate cathode material; The alumina-coated manganese-doped lithium iron phosphate cathode material prepared by the invention can effectively improve the conductivity and the charge-discharge capacity, increase the electric contact area, and further improve the cycle performance of the lithium ion battery.

Description

technical field [0001] The invention relates to the technical field of positive electrode materials for lithium ion batteries, in particular to a method for preparing an aluminum oxide-coated manganese-doped lithium iron phosphate positive electrode material. Background technique [0002] Since Japan developed the first lithium-ion battery in 1990, due to its high specific capacity, high working voltage, long cycle life, and no memory effect, lithium-ion batteries have penetrated into all aspects of people's lives, and communication equipment is inseparable. Opening it, transportation equipment also shows its use, especially with the miniaturization and flexible development of electronic products, the research and development of lithium-ion batteries has attracted much attention. [0003] In lithium-ion batteries, the performance of the cathode material affects the performance of the lithium-ion battery to a large extent. Lithium iron phosphate is used as the cathode materia...

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Problems solved by technology

[0003] In lithium-ion batteries, the performance of the cathode material affects the performance of the lithium-ion battery to a large extent. Lithium iron phosphate is used as the cathode material of lithium-ion batteries. Due to its high theoretical capacity, stable structure and cycle performance, it is the next generation of Lithium-ion battery cathode material is favored by people, but its disadvantages are also obvious. The electronic conductivity is relatively low, which is difficult to meet the requirements of high-rate charge and discharge of power batteries, and the diffusion rate of pure-phase lithium iron phosphate lithium ions is extremely low, so As a result, the actual specific capacity is not high and the high-rate performance is extremely poor. At the same time, the direct contact reaction between the lithium iron phosphate cathode material and the electrolyte affects the stability and cycle efficiency of the electrode cycle, which largely limits the large-scale application of lithium-ion batteries.

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