锂离子电池用Si-Mn复合电极的研究

Si-Mn Composite Anode Used for Li-ion Battery

利用机械球磨方法制得原子比为Si:Mn=3:5的硅-锰复合材料。利用XRD对材料进行物相分析,以锂片作为参比电极和对电极,通过充放电测试、循环伏安曲线研究了材料的电化学性能。XRD分析和电化学测试结果表明:在氩气气氛下球磨96h后所得材料为Si和Mn的混合物;电极片在压制压力为10MPa条件下首次嵌锂容量为400mA·h·g-1,充放电效率为72%。对电极的热处理改善了材料的循环性能。材料的首次嵌锂容量随着热处理温度的提高而降低。电极在350℃处理后其可逆容量在第40次循环可保持在192mA·h·g-1。

Si-Mn composites were prepared by ball-milling a mixture of Si and Mn powders （Si：Mn=3：5, atomic ratio）. The phase structures of the composites were analyzed by X-ray diffraction technology. Their electrochemical performances were investigated via charge-discharge experiments and cyclic voltamrnetry （CV） by using a cell with a lithium foil as the counter and reference electrode. The XRD patterns show that the materials prepared by 96 h ball-milling under argon atmosphere are composites consisting of Si and bin powders. Electrodes pressed with different pressures have different cyclic performance. The electrode pressed by 10MPa has a lithium insertion capacity of 400mA·h·g^-1 and a charge-discharge efficiency of 72%. Heat treatment enhances the cyclic performance of Si-Mn composites, and the initial lithium insertion capacity decreases with increasing heat treatment temperature. The electrode treated at 350℃ has a lithium insertion capacity of 290 mA·h·g^-1 and a charge-discharge efficiency of 68%. After forty cycles, the reversible capacity of the electrode treated at 350℃ may retain 192 mA·h·g^-1.