Preparation method of lithium vanadyl phosphate lithium vanadyl phosphate positive electrode material of lithium ion battery with core-shell structure

Abstract

The invention provides a preparation method of a lithium ion battery cathode material (lithium vanadyl phosphate) with a core-shell structure. The preparation method comprises the following steps: (1) mixing a lithium source, a vanadium source and a phosphorus source at a molar ratio of lithium ions to vanadium ions to phosphate ions being 1:1:1, and dissolving in water with reductant; (2) adjusting the pH value of the solution to be 6-9; (3) moving the solution into a high-pressure reaction kettle, heating and reacting at 200-400 DEG C for 10-72 hours, thus obtaining uniform sol; (4) taking out the sol and filtering, then drying at 60-120 DEG C in vacuum to obtain a precursor; and (5) placing the precursor in a sintering furnace, sintering at 300-600 DEG C for 2-15 hours under a non-reducing atmosphere, then carrying out heat treatment at 200-400 DEG C for 0.1-4.0 hours under an oxygen atmosphere, and finally naturally cooling to room temperature. According to the material lithium vanadyl phosphate provided by the invention, the core is LiVOPO4, the shell is a V2O5 thin layer with a nano thickness, the structure is particular, and the electrochemical performance is excellent.

Description

technical field [0001] The invention relates to a preparation method of lithium vanadyl phosphate lithium ion battery cathode material, in particular to a preparation method of a lithium ion battery cathode material lithium vanadyl phosphate with a core-shell structure. Background technique [0002] LiVOPO 4 It is a new type of lithium ion battery cathode material, which belongs to the phosphate series cathode material. 4+ / V 5+ Based on the redox pair, it has a higher charge-discharge platform (3.95VvsLi + ) and high theoretical specific capacity (156mAh / g), the energy density is 616Wh / Kg, which is higher than the commercialized lithium iron phosphate cathode material (598Wh / Kg), and lithium vanadyl phosphate has stable voltage platform and stable structure , good safety, cheap raw materials and other advantages, it shows great potential in the manufacture of lithium-ion power batteries. [0003] LiVOPO 4 Despite the above advantages, its low electronic conductivity se...

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Problems solved by technology

[0003] LiVOPO 4 Although it has the above advantages, its low electronic conductivity severely limits its electrochemical performance during high-rate charge and discharge.

Thanks to LiVOPO 4 The sintering atmosphere is generally in the air, and the chemical reaction is violent, which makes the traditional method of coating carbon to improve electronic conductivity meaningless in improving the material.

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