SiOC ceramic material used for preparing cathode of lithium ion battery, preparation method thereof and lithium ion battery

Abstract

The invention discloses a SiOC ceramic material used for preparing the cathode of a lithium ion battery, a preparation method thereof and a lithium ion battery prepared from the ceramic material. The SiOC ceramic material comprises silicon, oxygen and carbon, and the mol ratio of silicon to oxygen to carbon is 1: alpha: beta, wherein, alpha is 0.4 to 0.2, beta is 0.4 to 5.0, and alpha plus beta is 0.8 to 7.0. The preparation method comprises the following steps: preparing organosilicon polymers with a molecular formula of a(R1R2SiO)x(R3R4SiO2)y(R5R6SiO3)zb, wherein, a and b are terminated functional groups, R1, R2, R3, R4, R5 and R6 are functional groups, at least one of which is hydrogen groups or alkenyl groups, x is 0.3 to 1, y is 0 to 0.7, z is 0 to 0.5, and x plus y plus z is 1; preparing organic small molecular compounds which comprise active groups that can react with hydrogen groups, silanol groups or alkenyl groups; mixing the organosilicon polymers with the organic small molecular compounds, preparing the two into a copolymer through crossing and curing, and carrying out pyrolysis so as to obtain the SiOC ceramic material. The lithium ion battery provided in the invention has the characteristics of high capacity, good cycle performance and high reversible capacity.

Description

technical field [0001] The invention relates to the fields of composite materials and batteries, in particular to a SiOC ceramic material used for preparing lithium-ion batteries and a preparation method thereof. Background technique [0002] Compared with traditional secondary batteries, lithium-ion batteries have the advantages of high open circuit voltage, high energy density, long service life, no memory effect, no pollution, and small self-discharge, so their applications are becoming more and more extensive. The current commercial lithium-ion battery anode material is a carbon-based anode material, and its theoretical capacity is only 372mAh / g, and it has been developed close to the theoretical value. It cannot adapt to the miniaturization development of various portable electronic devices and the large-capacity and high-power requirements of electric vehicles. Extensive demand for chemical power sources. Therefore, it is imperative to find new anode material systems ...

AI Technical Summary

Problems solved by technology

[0009] First, the serious volume effect of silicon during the charge-discharge cycle leads to the collapse of the material structure;

[0010] Secondly, the irreversible transformation of silicon from crystalline state to disordered state during the process of intercalation and delithiation of lithium causes serious damage to the structure of the material;

[0011] Third, silicon has poor electrical conductivity, and the uneven reaction with lithium reduces the cycle performance of silicon materials

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