Composite hard carbon cathode material of lithium ion battery and preparation method thereof

Abstract

The invention discloses a composite hard carbon cathode material of a lithium ion battery and a preparation method thereof, aiming at improving the first coulombic efficiency. In the composite hard carbon cathode material, a coating object is coated outside a hard carbon matrix, a precursor of the hard carbon matrix comprises a thermoplastic resin which forms the hard carbon matrix by pyrolysis, and a precursor of the coating object is an organic matter. The preparation method comprises the steps of curing, pyrolyzing, pulverizing and coating. Compared with the prior art, a curing agent and adopant are added to the resin for curing, the cured mixture is taken as a carbon source, and then the carbon source is pyrolyzed and coated to finally obtain the composite hard carbon cathode material; and the first reversible capacity of the obtained composite hard carbon cathode material is more than 455.2mAh/g and the first coulombic efficiency thereof is more than 79.4% in the case of 0.2C, thus the obtained composite hard carbon cathode material has high capacity and high first coulombic efficiency, meets the requirement of the lithium ion battery with high capacity, high multiplying power and excellent high and low temperature cycle performance on the charge-discharge performances of the cathode material, has low production cost and is suitable for industrial production.

Description

Technical field [0001] The invention relates to a battery negative electrode material and a preparation method thereof, in particular to a lithium ion battery negative electrode material and a preparation method thereof. Background technique [0002] With the increasing demand for multifunctional portable electronic equipment in the information age and the rapid development of electric vehicles, the development of new lithium battery electrode materials with high specific energy, high rate, high safety, long life, and low cost has become an internationally important The frontier research field. The most successful carbon anode materials in the prior art include artificial graphite, mesophase carbon microsphere MCMB, and petroleum coke. However, its 372mAh / g specific capacity is too low, and it is increasingly unable to meet the requirements, and its fragile structure will lead to very limited stability, and it is also highly sensitive to electrolyte. Therefore, people turn thei...

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But its first charge and discharge efficiency is low, only about 45%

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