Preparation method of strontium and barium activated lithium iron phosphate positive pole material

Abstract

The invention discloses a preparation method of a strontium and barium activated lithium iron phosphate positive pole material. The preparation method is characterized by comprising the following steps: mixing a lithium source, an iron source, a phosphate radical source, and a strontium source utilized as a raw material according to the ratio of 1:(0.00002-0.00005):(0.0003-0.003):1:1; in an absolute ethyl alcohol medium, carrying out high-speed ball-milling for 20 hours at the rotation rate of 200r / mimn and drying at the temperature of 105-120 DEG C, thereby obtaining a front body, and placing the drying obtained front body in a high temperature furnace; and carrying out high-temperature calcination for 24 hours at 500-750 DEG C in a common pure nitrogen atmosphere on to obtain the strontium, barium activating lithium iron phosphate positive pole material. According to the invention, strontium and the barium are replaced because of the doping, the feature and the particle diameter of a product are effectively controlled, thereby obtaining a stable lithium iron phosphate compound, the crystal lattice of the lithium iron phosphate compound is activated, the lithium ion diffusion coefficient is improved, and the loading capacity achieves 160.52 m A h / g in the first time; a charge-discharge platform relative to lithium electrode potential is around 3.5V, the initial discharge capacity exceeds 168 m A h / g, and the capacity decays around 1.2% after the charging and discharging are circled for100 times; compared with the unmixed LiFePO4 contrast embodiment, the specific capacity and the cyclical stability are greatly improved.

Description

technical field [0001] The method for preparing a strontium and barium activated lithium iron phosphate positive electrode material of the invention belongs to a method for preparing a lithium battery positive electrode material, and in particular relates to a preparation method for a lithium iron phosphate battery positive electrode material. Background technique [0002] At present, the research status of lithium iron phosphate doping modification: lithium iron phosphate LiFePO4 is non-toxic, environmentally friendly, high in safety, rich in raw materials, high in specific capacity, stable in cycle performance, and low in price. The stable discharge platform with a theoretical capacity of 3.5V, the lithium iron phosphate material has high energy density, low price, and excellent safety, and is especially suitable for power batteries. But it has a higher resistivity. Due to lithium iron phosphate, the kinetics of LiFePO4 is not good at room temperature, and the rate perfor...

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Problems solved by technology

[0005] At present, there is a consensus that lithium iron phosphate has the advantages of good safety, no pollution, stable cycle performance, high specific capacity and low price, but it also has poor conductivity and the disadvantage of lower tap density