Preparation method of selenium and barium activated lithium iron phosphate anode materials

Abstract

The invention relates to a preparation method of selenium and barium activated lithium iron phosphate anode materials, which includes mixing raw materials of a lithium source, an iron source, a phosphoric acid root source, a selenium source and a barium source according to the following ratio by mole: 1 part of lithium, 0.00002 to 0.00005 part of selenium, 0.0003 to 0.003 part of barium, 1 part of iron and 1 part of phosphoric acid root, milling the raw materials in an absolute ethyl alcohol medium for 20 hours through a high-speed ball with 200r / mimn rotating speed, drying the raw materials under the temperature between 105 DEG C and 120 DEG C to obtain a precursor, placing the precursor obtained by drying in a high-temperature furnace and conducting high-temperature calcination on the precursor under the temperature between 500 DEG C and 750 DEG C for 24 hours in an atmosphere of common pure nitrogen to obtain the niobium and barium activated lithium iron phosphate anode materials. Due to the fact that a small quantity of selenium and barium is mingled for replacement, appearance and particle diameter of products can be favorably controlled to obtain stable lithium iron phosphate compound. Lattice of the products is activated, diffusion coefficient of lithium ions is improved, and first discharging capacity of obtained materials reaches 160.52mAh / g. Electrode potential of a charging-discharging platform is about 3.5V relative to lithium, initial discharging capacity surpasses 168mAh / g, and the capacity attenuates by about 1.2% after 100 times of charging-discharging circulation. Compared with unmingled LiFePO4 contrast embodiment, specific capacity and circulation stability are greatly improved.

Description

technical field [0001] The invention relates to a method for preparing a positive electrode material activated by selenium and barium iron phosphate, which belongs to a method for preparing a positive electrode material for 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