Long cycle high rate natural graphite-based composite material for lithium ion battery and preparation method and application thereof

By forming a hard carbon coating layer on and inside natural graphite, the problem of lithium deposition in natural graphite anode materials at high rates is solved, improving their cycle performance and charge/discharge efficiency, thus realizing a lithium-ion battery anode material with high rate performance and long life.

CN117317152BActive Publication Date: 2026-06-19GUANGDONG DONGDAO NEW ENERGY +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
GUANGDONG DONGDAO NEW ENERGY
Filing Date
2022-06-22
Publication Date
2026-06-19

AI Technical Summary

Technical Problem

Existing natural graphite anode materials are prone to lithium plating under high-rate conditions, which leads to a decrease in battery capacity and safety performance, and micro-expansion treatment reduces cycle performance.

Method used

A hard carbon coating layer was formed on the surface and inside of natural graphite using vacuum impregnation and isostatic pressing techniques to repair the defects of micro-expanded graphite. This process was used to prepare natural graphite-based composite materials to improve their charge-discharge performance and cycle life at high rates.

Benefits of technology

Rapid charging and discharging under high current is achieved. The composite material has high reversible capacity, high initial coulombic efficiency, significantly improved cycle life, stable charging and discharging process, and simultaneous repair of defects.

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Abstract

This invention provides a long-cycle, high-rate natural graphite-based composite material for lithium-ion batteries, its preparation method, and its application. The preparation method includes the following steps: mixing natural graphite, an oxidant, and an organic acid and heat-treating to obtain micro-expanded graphite; adding a first-part hard carbon precursor to an organic solvent to obtain a hard carbon precursor solution; placing the micro-expanded graphite in a reaction vessel, drawing the hard carbon precursor solution into the reaction vessel to obtain a mixture, heating to remove the organic solvent to obtain a mixed material; isostatically pressing the mixed material to obtain graphite blocks, then breaking them down into micro-powder; mixing the micro-powder, the second-part hard carbon precursor, and the organic solvent evenly, followed by spray drying and carbonization to obtain a natural graphite-based composite anode material. This preparation method allows for the simultaneous repair and integration of surface defects in both the internal and external coiled graphite layers of the micro-expanded graphite, improving the lifespan of the composite material.
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