Beryllium-barium activated lithium iron phosphate cathode material

Abstract

The invention provides a beryllium-barium activated lithium iron phosphate cathode material which has a general chemical formula of LiBexBay FePO4, wherein, x is in a range of 0.00002 to 0.00005, y is in a range of 0.0003 to 0.003, and the mol ratio of Li, Be, Ba, Fe and P satisfies the following equation: 1 mol Li: 0.000020-0.00005 mol Be: 0.0003-0.003 mol Ba: 1 mol Fe: 1 mol P. Doping of a small amount of substituting beryllium and barium is favorable for controlling the morphology and particle size of a product and for obtaining a stable lithium iron phosphate compound, crystal lattice of the cathode material is activated, the diffusion coefficient of lithium ions is improved, and the initial discharge capacity of the cathode material is up to 160.52 mAh; the charge and discharge platform of the cathode material has a potential of about 3.5 V relative to a lithium electrode and has an initial discharge capacity of more than 168 mAh / g, and the capacity of the charge and discharge platform attenuates about 1.2% after 100 cycles of charge and discharge; compared to undoped LiFePO4 in contrast embodiments, the doped lithium iron phosphate cathode material in the invention has greatly improved specific capacity and cycling stability.

Description

technical field [0001] The beryllium 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 c...

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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