Preparation method of yttrium-containing lithium ion battery cathode material lithium titanate carbon-coated composite material

Abstract

The invention provides a preparation method of an yttrium-containing lithium ion battery cathode material lithium titanate carbon-coated composite material. The preparation method is characterized in that the preparation method comprises following concrete steps: (1) weighing a soluble lithium compound, titanium dioxide (anatase type) and a yttrium compound according to a stoichiometric ratio of an target compound of Li[x]YpTi[y]Oz, adding into a ball milling jar, adding an organic micromolecule carbon source precursor and mixing, and performing ball milling in an uniform medium and drying, wherein the x is more than 0 and not more than 8, the p is more than 0 and less than 5, the y is more than 0 and not more than 6, the z is not less than 1 and not more than 12, and the ratio of x to y is not less than 1 / 2 and not more than 2; (2) maintaining the temperature of the dried powder in air or an inert gas at 300-600 DEG C for 2-20 h to obtain a sintering precursor; and (3) mixing the sintering precursor obtained in the step (2) and an organic macromolecule carbon source precursor, performing ball milling in an uniform medium and drying; and maintaining the temperature in air or the inert gas at 600-900 DEG C for 2-30 h to obtain a finished product of lithium titanate powder. The material shows excellent rate performance. The preparation method significantly improves the conductivity of the lithium titanate product, and the material shows the excellent rate performance and excellent cycle performance, and is suitable to be used in a power cell.

Description

technical field [0001] The invention relates to a preparation method of a battery electrode material, in particular to a preparation method of a lithium titanate-coated carbon composite material for an yttrium-containing lithium ion battery negative electrode material. Background technique [0002] Due to its high energy density, small self-discharge, and no memory effect, lithium-ion batteries have a dominant position in the secondary battery market and are widely used in mobile communications, notebook computers, mobile phones, video cameras, cameras, portable instruments and other fields. It has rapidly developed into one of the most important secondary batteries at present. With the increasing miniaturization and miniaturization of electronic products, the research and application of lithium-ion batteries have been paid more and more attention. At present, most commercial lithium-ion batteries use carbon materials such as graphite as the negative electrode and LiCoO 2 ...

AI Technical Summary

Problems solved by technology

Although compared with metal lithium, carbon materials have greatly improved in terms of safety performance and cycle performance, but there are still shortcomings that are difficult to overcome: they react with the electrolyte to form a surface passivation film, resulting in electrolyte consumption and the first time. The coulombic efficiency is low; the electrode potential of the carbon electrode is similar to that of metal lithium. When the battery is overcharged, metal lithium may still be precipitated on the surface of the carbon electrode, forming dendrites and causing a short circuit, causing the battery to explode and causing safety problems.

[0004] After searching the existing technology, it is found that the traditional high-temperature solid-phase method is generally adopted for the preparation of lithium titanate in large quantities. Li obtained the ideal spinel structure 4 Ti 5 o 12 The advantage of this method is that the process is simple and it is easy to produce on a large scale. The disadvantage is that the particles of the product are relatively coarse, generally micron-sized

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