Calcium and barium activated lithium iron phosphate positive pole material

Abstract

The invention discloses a calcium and barium activated lithium iron phosphate positive pole material. The general formula of the positive pole material is LiCaxFeyPO4, wherein x=0.002-0.005, y=0.0003-0.003, the mol ratio of Li, Ca, Ba, Fe and P is 1.0:(0.002-0.005):(0.0003-0.003):1:1; as the doping of a small amount of Ca and Ba for substitution, 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 155.52 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 164 m A h / g, and the capacity decays around 3.0% after charging and discharging are circled for 100 times; compared with the unmixed LiFePO4 comparing embodiment, the specific capacity and the cyclical stability are greatly improved; and as the price of Ba is over hundreds of times lower than that of Li, the manufacturing cost can be reduced by more than 10 times.

Description

technical field [0001] The calcium and barium activated lithium iron phosphate positive electrode material of the invention belongs to a lithium battery positive electrode material, in particular to 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 performance is extremely poor. Researchers at home and abroad have used methods such as coa...

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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