Preparing method for aluminium and barium activated lithium iron phosphate positive electrode material

Abstract

The invention relates to a preparing method for an aluminium and barium activated lithium iron phosphate positive electrode material, which comprises the following steps of: mixing raw materials of a lithium source, an iron source, a phosphate radical source, an aluminium source and a barium source of the positive electrode material according to proportions of 1 mol of Li to 0.002-0.005 mol of Alto 0.0003 mol of Ba to 1 mol of Fe to 1 mol of P, carrying out high-speed ball milling for 20h at a revolving speed of 200 r / min in an absolute ethyl alcohol medium, drying in the temperature of 105 DEG C to 120 DEG C to obtain a precursor, placing the precursor obtained by drying in a high temperature furnace, and calcining for 24h in the high temperature of 500 DEG C to 750 DEG C at a common pure nitrogen atmosphere, thereby obtaining the aluminium and barium activated lithium iron phosphate positive electrode material of the invention. A small quantity of substituted calcium and barium doped in the obtained material are beneficial to the control of the appearance and the grain size of a product and the obtaining of the stable lithium iron phosphate compound; the crystal lattice of the positive electrode material is activated, thereby increasing diffusion coefficients of lithium ions; the initial discharge capacity of the obtained positive electrode material reaches 155.52mAh / g; a relative lithium electrode potential of a charge-discharge platform of the positive electrode material is about 3.5V; after the initial discharge capacity of the positive electrode material exceeds 164mAh / g and the positive electrode material undergoes 100 times of charge-discharge circulations, the capacity is attenuated by about 3.0%; and compared with the reference embodiment of the undoped LiFePO4, the positive electrode material has the advantages that the specific capacity and the circulation stability are increased greatly; and as the price of the barium is higher than that of lithium by more than a hundred times, the production cost can be reduced by more than ten times.

Description

technical field [0001] The invention discloses a method for preparing an aluminum and barium activated lithium iron phosphate positive electrode material, which belongs to a method for preparing a lithium battery positive electrode material, and in particular relates to a method for preparing 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 r...

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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