锂离子电池炭负极的结构与特性及其电化学性能

通过计算边缘碳原子及表面碳原子含量计算,研究边缘碳及表面碳原子含量对炭材料的电化学性能的作用机理。导出炭材料的结构与物理特性对炭材料的嵌锂性能的影响。通过对不同形貌、粒径、比表面积及有序程度的人造石墨、中间相炭微球及热解炭的电化学性能的研究,验证该机理的正确性。应用这一机理分析对人造石墨进行热处理改性,以及在人造石墨表面包覆无定形炭的改性作用。研究结果表明:边缘碳及表面碳原子的含量对固体-电解质中间相(SEI)膜的形成以及SEI膜的均匀、稳定性具有重要的作用,从而影响炭材料的首次不可逆容量及循环性能。

Mechanism for effects of structure and properties of carbon on its electrochemical characteristics as anode of lithium ion battery

Based on calculation of fraction of carbon atoms at surface and edge sites,the mechanism for effects of fraction of carbon atoms at surface and edge sites on the electrochemical characteristics of carbon materials was developed.The effects of structure and physical properties on electrochemical characteristics of carbon anode were educed.The mechanism is proved to be reasonable by investigation on electrochemical characteristics of artificial graphite,meso-carbon microbeads and disordered carbon with different structures,appearances,particle sizes and specific surface areas.The mechanism was also successfully applied to study effects of mild oxidation and coating disordered carbon on the performance of artificial graphite.The result show that the fraction of carbon atoms at surface and edge sites plays an important role in the formation of solid-electrolyte interface(SEI) and determines its performances such as uniformity and stability,then causes significant influences on the irreversible capacity and cycling capability of the carbon anode.