石墨化中间相炭微球表面镀银的电化学性能

来源期刊：中南大学学报(自然科学版)2003年第6期

论文作者：王红强 李新海 郭华军 张宝 郭永兴

文章页码：615 - 618

关键词：中间相炭微球;化学镀银;放电容量;锂离子电池;循环性能

Key words：mesocarbon microbeads; electroless plating silver; discharge capacity; lithium ion battery; cycling ability

摘    要：采用化学镀的方法在中间相炭微球的表面镀覆金属银,通过扫描电镜分析镀银后炭微球的表面形貌,利用X射线衍射对试样进行物相分析.将镀银的中间相炭微球用作锂离子电池负极材料,测试其电化学性能.研究结果表明:金属银镀覆在中间相炭微球的表面,随着镀银含量的增加,镀银中间相炭微球的首次放电容量升高,银含量16.5%的中间相炭微球的首次放电容量升高12.6 mA·h/g;在湿度为25%的气氛中搁置12 h后,未镀银的炭微球的放电容量降低16.3 mA·h/g,循环稳定性变弱,20次循环后容量保持率为74.6%,而镀银量为16.5%炭微球的首次放电容量只降低6.1 mA·h/g,并且循环稳定性强,20次循环后容量保持率为95.8%,说明镀银后中间相炭微球在潮湿条件下的电化学性能得到改善.

Abstract: Silverwas coated on the surface of graphitized mesocarbon microbeads (MCMBs) by electroless plating. The Ag-coated MCMBs were observed by SEM and analyzed by XRD, the electrochemical performance of Ag-coated MCMBs used as active anode material for lithium ion batteries is studied. It is found that Ag was plated on the surface of graphitized MCMBs successfully; the discharge capacity of Ag-coated MCMBs is increased with the enhancement of Ag. The discharge capacity of 16.5% (mass fraction) Ag-coated MCMBs is 12.6 mA·h/g higher than that of uncoated MCMBs in the first charge-discharge cycle. After being held at 25% humidity atmosphere for 12 h, the discharge capacity of MCMBs is decreased 16.3 mA·h/g and haveworse cyclabilityholding74.6% discharge capacity of that in the first cycle after 20 cycles. For the Ag-coated MCMBs, its discharge capacity was decreased 6.1 mA·h/g, and it has good cy- cleability holding95.8% discharge capacity in the first cycle after20 cycles. The electrochemical performance of MCMBs in humidity atmosphere is significantly improved by Ag-coated on the surface MCMBS.