Method for preparing antimony and barium activated lithium iron phosphate cathode material

Abstract

The invention discloses a method for preparing an antimony and barium activated lithium iron phosphate cathode material. The method comprises the following steps of: mixing a lithium source, an iron source, a phosphate group source, an antimony source and a barium source which serve as raw materials according to the ratio of Li to Sb to Ba to Fe to P of 1:(0.00002-0.00005):(0.0003-0.003):1:1, performing high-speed ball milling in an absolute ethanol medium at the rotating speed of 200r / min for 20 hours, drying at the temperature of between 105 and 120 DEG C, and thus obtaining a precursor; and putting the dried precursor into a high temperature furnace, calcining in a nitrogen atmosphere at the temperature of between 500 and 750 DEG C for 24 hours, and thus obtaining the antimony and barium activated lithium iron phosphate cathode material. A small amount of antimony and barium is doped, so that control over the appearance and the particle size of a product is facilitated, a stable lithium iron phosphate compound is obtained, the crystal lattice of the material is activated, a lithium ion diffusion coefficient is improved, and the material has the initial discharging capacity of 160.52mAh / g; a charging / discharging platform of the material has a relative lithium electrode potential of about 3.5V, and material has the initial discharging capacity of more than 168mAh / g and has the capacity which is reduced by about 1.2 percent after 100-time charging / discharging operation; and compared with an undoped LiFePO4 comparison embodiment, the method has the advantage that the specific capacity and the circulating stability of the material are greatly improved.

Description

technical field [0001] The antimony and barium activated lithium iron phosphate positive electrode material preparation method of the present invention belongs to a lithium battery positive electrode material preparation method, in particular to a lithium iron phosphate battery positive electrode material preparation method. 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 performance is extremely ...

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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