沥青包覆Si/G/C复合材料的制备与性能研究

以沥青为包覆剂,通过喷雾干燥和高温热解工艺制备了一系列Si/G/C复合负极材料。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)以及恒电流充放电测试(CC)等手段研究了沥青热解温度对Si/G/C复合负极材料结构、形貌以及电化学性能的影响。测试结果表明,前驱体分别在900、1 000、1 050、1 100、1 150、1 200℃分解,1 050℃分解得到的复合负极材料综合电化学性能更加优异,在100 mA/g的充放电电流下,其首次放电比容量为714.9 mAh/g,首次库仑效率为84.0%,循环30周后的容量保持率为84.9%。

Study on preparation and property of pitch-coated silicon/graphite/carbon composite

Using pitch as carbon source,a series of silicon/graphite/amorphous carbon composites in a core-shell structure were prepared by spray drying with subsequent pyrolysis process.The effects of pyrolytic temperature of pitch on the structure,morphology and electrochemical performance of the composite were studied by XRD,SEM,TEM and galvanostatic charge-discharge test.The results demonstrate that the precursor is decomposed at different temperatures of 900,1 000,1 050,1 100,1 150,1 200 ℃.The comprehensive electrochemical properties of silicon/graphite/amorphous carbon composite decomposed at 1 050 ℃ are better than others.Its initial discharge specific capacity is 714.9 mAh/g while the initial coulombic efficiency is 84.0％ at a constant current density of 100 mA/g.After 30 cycles,its capacity retention reaches 84.9％.