Preparation method of low-cost high-performance lithium iron phosphate material

Abstract

The invention discloses a preparation method of a low-cost high-performance lithium iron phosphate material. The preparation method comprises the steps that an iron source, a phosphorus source and a lithium source are mixed according to the molar ratio of 1:(0.85-1):(0.9-1), a carbon source of which the weight accounts for 3%-10% of the total weight of the mixture is added, and mixing is continuously conducted to obtain a mixed material, wherein a mixture of ferric oxide and ferric orthophosphate is adopted as the iron source, lithium dihydrogen phosphate is adopted as the phosphorus source, lithium carbonate is adopted as the lithium source, and saccharose or maltose is adopted as the carbon source; the mixed material is added into a solvent to be ground for 10 hours to 20 hours, drying is conducted, and then a lithium iron phosphate precursor is obtained; a modifying agent solvent and the lithium iron phosphate precursor are mixed and then added into tartaric acid, stirring is conducted for 5 hours to 10 hours, and then drying is conducted at 60 DEG C to 80 DEG C to obtain lithium iron phosphate powder; the lithium iron phosphate powder is subjected to two-phase sintering under protection of inert gas to obtain the lithium iron phosphate material. According to the preparation method, the mixture of ferric oxide and ferric orthophosphate is adopted as the iron source, and therefore the raw material cost is reduced; meanwhile, cladding is conducted through a modifying agent, and therefore the electrical conductivity of the material is improved.

Description

technical field [0001] The invention relates to lithium ion battery technology, in particular to a method for preparing a low-cost and high-performance lithium iron phosphate material. Background technique [0002] Lithium-ion batteries are regarded as one of the most efficient electrochemical energy storage systems due to their high specific energy, high specific power, and environmental friendliness. Among them, lithium iron phosphate material, as the positive electrode material of lithium ion battery, has the advantages of rich raw material source, low price, green environmental protection, high theoretical specific capacity (about 170mAh / g), long life, safety and good thermal stability, etc., making it a new Ideal electrode material in the field of energy and power vehicles. However, due to the low electronic conductivity and ion mobility of lithium iron phosphate, its own conductivity is affected, thereby affecting the cycle capacity and the rate charge and discharge p...

AI Technical Summary

Problems solved by technology

However, due to the low electronic conductivity and ion mobility of lithium iron phosphate, its own conductivity is affected, which affects the cycle capacity and the rate charge and discharge performance of the battery.

[0003] The preparation method of lithium iron phosphate material is mainly made by mixing a single iron phosphate or iron oxide and a lithium source. Due to the use of a single iron source to prepare lithium batteries, there are many limitations. For example, lithium iron phosphate prepared by using iron phosphate as an iron source The battery performance is excellent, but the price and cost are high; while only using iron oxide as the iron source, although the price is low, the material performance is poor, which affects the battery performance

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