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

Abstract

The invention relates to a method for preparing a zinc and barium activated lithium iron phosphate cathode material. Raw materials for preparing the zinc and barium activated lithium iron phosphate cathode material include lithium sources, ferrum sources, phosphate radical sources, zinc sources and barium sources, all the raw materials are mixed according to a proportion of 1 mol Li : 0.00002-0.00005 mol Zn : 0.0003-0.003 mol Ba : 1 mol Fe : 1 mol P, performed with ball milling at high speed with rotation speed at 200 r / min in absolute ethyl alcohol media, dried at 105-120 DEG C to obtain a precursor, and the precursor obtained through drying is placed in a high temperature furnace to be roasted for 24 hours at 500-750 DEG C high temperature in nitrogen atmosphere so as to obtain the zinc and barium activated lithium iron phosphate cathode material. Due to the fact that a small amount of doping replaces zinc and barium, control on shape and particle size of products is facilitated, stable lithium iron phosphate compound can be obtained, crystal lattice of the lithium iron phosphate compound is activated, lithium-ion diffusion coefficient is enlarged, and first discharge capacity of obtained materials reaches 160.52 mAh / g. A charge-discharge platform of the zinc and barium activated lithium iron phosphate cathode material is about 3.5 V relative to electric potential of lithium electrodes, first discharge capacity of the charge-discharge platform surpasses 168 mAh / g, and capacity of the charge-discharge platform is reduced to about 1.2% after 100 times of charge-discharge circulation. Compared with a lithium iron phosphate (LiFePO4) comparison embodiment without doping, the zinc and barium activated lithium iron phosphate cathode material is greatly improved in both specific capacity and cycle stability.

Description

technical field [0001] The method for preparing a positive electrode material of zinc and barium activated lithium iron phosphate according to the invention belongs to a method for preparing a positive electrode material of a lithium battery, and in particular relates to a method for preparing a positive electrode material for a lithium iron phosphate battery. 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, an...

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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