摘要
用碳热还原法制备了锡-石墨复合材料,通过XRD及SEM、恒流充放电循环、慢速扫描循环伏安和电化学阻抗测试等方法对其电化学嵌脱锂性能进行了研究.结果表明,SnO2被石墨还原成金属Sn圆球颗粒,球粒平均尺寸4μm,均匀分散,部分附着在片状石墨上.该材料的首次嵌、脱锂比容量分别可以达到887和615mA-h/g,库仑效率为69%,循环15次后的脱锂比容量为387mA-h/g,高于石墨,容量保持率为63%,平均容量损失率为2.5%/次。
Tin-graphite composite material was prepared by carbothermal reduction method from SnO2 and graphite in Ar atmosphere. The material was characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Electrochemical lithium insertion- extraction character of the material was determined by constant current charge-discharge, slow scanning cyclic voltammetry （CV）, and electrochemical impedance spectrometry （EIS） methods. The results of XRD and SEM show that spherical metallic Sn particles reduced from SnO2 are separated in graphite. The initial lithium insertion-extraction special capacities of the material can reach to 887 and 615 mA·h/g respectively, and initial Coulombic efficiency 69%. Even after 15 cycles, tin-graphite composite material still shows high extraction special capacities as 387 mA·h/g, the high capacity retention at the 15^th cycle as 63% and an excellent cycle performance with only 2.5% capacity loss per cycle.
出处
《过程工程学报》
EI
CAS
CSCD
北大核心
2008年第2期399-403,共5页
The Chinese Journal of Process Engineering
基金
国家重点基础研究发展规划(973)基金资助项目(编号:2002CB211800)
关键词
锂离子电池
碳热还原
锡-石墨复合材料
电化学阻抗光谱
Li-ion battery
carbothermal reduction
tin-graphite composite material
electrochemical impedance spectrometry
