Preparation method of carbon-coated lithium iron manganese phosphate positive electrode material

Abstract

The invention relates to a preparation method of a carbon-coated lithium iron manganese phosphate positive electrode material, which comprises the following steps: preparing a transition metal salt solution A, a phosphorus solution B and an ammonia water solution C according to the molar ratio of Mn to Fe, and simultaneously dropwise adding the solutions into a reaction kettle to prepare a lithiumiron manganese phosphate positive electrode material precursor; and preparing a lithium source from the precursor according to a molar ratio, adding a coating carbon source and a doped metal compound, and calcining under the protection of an inert atmosphere to obtain the carbon-coated lithium iron manganese phosphate positive electrode material. According to the preparation method of the carbon-coated lithium iron manganese phosphate positive electrode material, the formation of an impurity phase is effectively reduced, and the oxidation phenomenon possibly generated in the reaction is greatly inhibited; the material is modified by adopting conductive carbon coating and ion doping, so that the electronic conductivity of the material is improved, the Jahn-Teller effect of Mn < 3 + > is weakened, the cycling stability of the material is improved, and the practical application of the carbon-coated lithium iron manganese phosphate positive electrode material is greatly promoted.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a preparation method of a carbon-coated lithium manganese iron phosphate cathode material. Background technique [0002] In recent years, lithium-ion batteries have made great achievements in the fields of consumer electronics, energy storage power stations, and electric vehicles. Cathode materials, as one of the key materials in lithium-ion battery systems, have received extensive attention. At present, lithium cobalt oxide, lithium iron phosphate, lithium manganese oxide and nickel cobalt lithium manganese oxide ternary cathode materials are the most marketable materials. Among them, lithium iron phosphate has been recognized by the market for its advantages of large capacity, safety and environmental protection, long life, and wide operating temperature range, and has become one of the most widely commercialized lithium-ion cathode materials. Proble...

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Problems solved by technology

However, its disadvantages are also relatively prominent. The microscopic contact of raw materials is not sufficient, and the mixing effect is limited, resulting in uneven phases of the synthesized products, a wide range of particle size distribution, poor product consistency, prone to impurities, and a longer synthesis cycle. , higher energy consumption

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