Preparation method of germanium-doped high-energy-density lithium cobaltate composite positive material

Abstract

The invention relates to a preparation method of a germanium-doped high-energy-density lithium cobaltate composite positive material. The chemical formula of the germanium-doped composite lithium cobaltate is as follows: LiCo<1-x-y-z>Mgx AlyGezO2, wherein x is 0.22 to 0.3, y is 0.15 to 0.25, and z is 0.035 to 0.05. The method comprises the following steps of (1) preparing high-density spherical cobaltosic oxide; (2) smelting lithium oxide, cobaltosic oxide, aluminum oxide, magnesium oxide and germanium oxide, cooling, ball milling the mixture, and sintering the mixture to obtain a precursor of the germanium-doped lithium cobaltate composite positive material; and (3) mixing the precursor and a mixture of acetylene black and phenolic resin to be sintered to obtain a product. According to the prepared germanium-doped lithium cobaltate composite positive material, the high-purity high-density cobaltosic oxide is adopted as a raw material, so that the energy density of the composite material is improved; the Ge is doped while Al and Mg are doped so as to improve the activity and stability of the substances, and carbon cladding is also adopted in the preparation process, so that the conductivity and stability of the material can be improved.

Description

Technical field [0001] The invention relates to a preparation method of germanium-doped lithium cobaltate composite cathode material with high energy density. Background technique [0002] With the increasing consumption of fossil energy and the increasing demand for energy, the research and development of new energy materials is imminent. Electric energy has been popularized and used as early as the last century, and batteries are one of the common tools for using electric energy. Lithium-ion batteries are widely researched and used now. Due to the advantages of high energy density, long service life, low self-discharge rate and no memory effect of lithium-ion batteries, lithium-ion batteries are attracting the attention of scientists all over the world. At present, lithium battery cathode materials that have been marketed include lithium cobaltate, multi-component materials, lithium manganate and lithium iron phosphate, etc., and lithium cobaltate is currently the most ma...

AI Technical Summary

Problems solved by technology

When preparing lithium cobaltate, the cobalt tetroxide used is mainly prepared by calcining cobalt oxalate and cobalt carbonate, but because the synthesized cobalt oxalate and cobalt carbonate are irregular particles, after firing, the obtained cobalt tetroxide is also amorphous, resulting in When synthesizing lithium cobaltate, the tap density will be reduced, the volume of the battery will be increased, and the calcination will reduce the chemical activity of tricobalt tetroxide, which will eventually affect the electrochemical properties of lithium cobaltate

[0004] When the particle size of the previous lithium cobalt oxide is below 10 microns, its electrochemical performance is good and its cycle performance is excellent, but its compaction density is low, which cannot meet the increasing demand for energy density.

Although lithium cobalt oxide with a particle size of more than 10 microns can increase the volumetric energy density of the battery, its cycle performance cannot meet market demand due to its poor electrochemical activity.