Preparation method of lithium iron phosphate

Abstract

The invention discloses a preparation method of lithium iron phosphate. The method comprises the following steps: adding water into ferric chloride and lithium chloride in a molar ratio of 1: (1.03-1.05), and carrying out stirring and mixing to obtain a mixed solution; mixing tributyl phosphate and an N235 extracting agent according to a volume ratio of (6-10): 1, and carrying out uniform mixing under stirring to obtain an extracting agent; subjecting the mixed solution and the extracting agent to 6-8 stages of countercurrent extraction, and performing phase splitting to obtain an organic phase and a water phase; allowing the organic phase to enter a combustion furnace in a spray state, introducing air at the same time for combustion at a temperature of 300 DEG C to 450 DEG C, and performing dust collection to obtain a combustion material; and putting the obtained combustion material into a roller way furnace, performing calcining under the protection of an inert atmosphere, performingcooling to obtain a calcined material, carrying out jet milling on the calcined material, performing screening, and removing iron to obtain lithium iron phosphate. The method is simple in process andshort in process flow and can prepare the lithium iron phosphate material with high conductivity, low internal resistance, and excellent electrical properties.

Description

technical field [0001] The invention relates to a preparation method of lithium iron phosphate, which belongs to the technical field of lithium batteries. Background technique [0002] Lithium iron phosphate is currently the mainstream battery cathode material. In the early stage, due to the guidance of subsidy policies, the market share gradually shrank. However, after the subsidy retreated, the cost advantage of lithium iron phosphate batteries gradually became prominent. At the same time, as one of the main application scenarios of lithium iron phosphate batteries, new energy buses may receive further policy support, which will benefit the lithium iron phosphate battery industry; for consumers in third- and fourth-tier cities and even towns, the price is low and the service life is long Lithium iron phosphate batteries are more competitive. In addition, on the whole, compared with foreign manufacturers, my country's lithium iron phosphate battery has obvious advantages i...

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Problems solved by technology

[0005] At present, the preparation method of lithium iron phosphate generally adopts the carbon coating method, although the conductivity can be greatly improved, but for the inside of the single crystal particle of lithium iron phosphate, because it is a pure lithium iron phosphate particle, the conductivity in this particle is still Very poor, the conventional method is to use doping to achieve, but after doping, lithium iron phosphate has an impurity phase, which has some negative effects on the cycle performance of lithium iron phosphate

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