Preparation method for low-temperature nanometer lithium iron phosphate cathode material

Abstract

The invention discloses a preparation method for a low-temperature nanometer lithium iron phosphate cathode material. The preparation method comprises the following steps of: adding a lithium source compound, a ferric source compound, a phosphorous source compound and water according to a proportion for mixing, adding metal ion doped oxide and a primary carbon source for mixing, performing primary high-energy superfine pulverization for 2 to 3 hours, performing spray-drying to obtain powder, and performing sieving; pre-treating the powder in an inert atmosphere at the temperature of 300 to 500 DEG C for 2 to 10 hours, performing cooling, adding a secondary carbon source and water, stirring the mixture, performing secondary high-energy superfine pulverization to obtain spherical powder, and performing sieving; and performing jet milling on the spherical powder, performing treatment in the inert atmosphere at 500 to 600 DEG C for 6 to 30 hours, performing thermal treatment at the high temperature of 600 to 900 DEG C for 10 to 30 hours, and performing cooling to obtain the low-temperature nanometer lithium iron phosphate cathode material with the granularity of 60 to 70 nanometers. When the low-temperature nanometer lithium iron phosphate cathode material is used for manufacturing the anode of a lithium ion battery, the battery has high low-temperature discharge performance.

Description

technical field

[0001] The invention relates to the preparation technology of lithium ion battery cathode materials, in particular to a preparation method of low-temperature nano lithium iron phosphate cathode materials. Background technique

[0002] As a cathode material for lithium-ion batteries, lithium iron phosphate has the advantages of good safety performance, excellent cycle performance and environmental friendliness, and is rich in raw materials and high specific capacity (theoretical capacity is 170mAh / g, energy density is 550Wg / Kg). However, the lithium iron phosphate cathode material also has the following three problems: (1) According to its lithium ion deintercalation migration model, the ion conductivity and electronic conductivity of pure lithium iron phosphate are both low, and the electronic conductivity Se is 10 -9 s / cm order of magnitude, while the ion transmission rate Si is 10 -11 s / cm order, the two directly lead to low electrode transmission rate Sw ...

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