Preparation method of magnesium-aluminum-vanadium co-doped lithium cobalt oxide positive electrode material

Abstract

The invention discloses a preparation method of a magnesium-aluminum-vanadium co-doped lithium cobalt oxide positive electrode material, which comprises the following steps: a, cobalt oxide, lithium carbonate, magnesium oxide, aluminum oxide and ammonium vanadate raw materials are uniformly mixed, the molar ratio of the lithium element to the cobalt element is 1.04-1.06, the mass fraction of the magnesium oxide is 0.05-0.2%, the mass fraction of the aluminum oxide is 0.05-0.5%, the mass fraction of the ammonium vanadate is 0.05-0.5%, and the molar ratio of the lithium element to the cobalt element is 1.04-1.06; the mass fraction of the ammonium vanadate is 0.05%-0.5%; b, putting the raw materials mixed in the step a into calcining equipment at 500-1080 DEG C, sintering for 2-20 hours at a constant temperature, cooling to room temperature after sintering, and taking out; and c, crushing and sieving the product obtained in the step b to obtain the magnesium-aluminum-vanadium co-doped lithium cobalt oxide positive electrode material. By doping magnesium, aluminum and vanadium elements, the stable cycle performance of lithium cobalt oxide under 4.5 V voltage is improved, and the capacity is better under high-voltage charging and discharging conditions.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of a magnesium-aluminum-vanadium co-doped lithium cobalt oxide positive electrode material. Background technique [0002] Due to the advantages of high working voltage, small size, light weight, high specific energy, no pollution, small self-discharge, and recyclable use, lithium-ion batteries have become an ideal energy source for development in the 21st century. The development process of cathode materials, which are the main components of lithium-ion batteries, restricts the development of lithium-ion batteries to a large extent. Lithium cobalt oxide (LiCoO 2 ) is the first to be commercialized because of its simple preparation process, large specific capacity, good cycle performance and safety performance compared with other cathode materials. Lithium cobalt oxide has the disadvantages of relatively low charging capacity, slow charging speed, and sh...

AI Technical Summary

Problems solved by technology

[0009] In the prior art, Al is often used 3+ As a dopant material, since Al 3+ with Co 3+ have similar ionic radii, while α-LiAlO 2 with LiCoO 2 have a similar layered structure, the introduction of Al will not destroy the layered structure of the material, so the introduction of Al 3+ Can improve the stability of lithium cobalt oxide cathode material structure, but Al 3+ Doping can not improve the relatively low charging capacity and slow charging speed of lithium cobalt oxide materials.

Therefore, it is necessary to look for other doping materials, with Al 3+ Co-doped lithium cobalt oxide, while improving the disadvantages of relatively low charging capacity, slow charging speed, and short service life of lithium cobalt oxide positive electrode materials

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