以聚乙烯醇缩丁醛为碳源,在一氧化硅(SiO)表面包覆碳层,再与膨胀石墨复合,制备锂离子电池负极用SiO/C/膨胀石墨复合材料。无定形碳层能提高SiO的导电性;膨胀石墨的柔韧性良好,能缓冲SiO的体积膨胀并保持电子通路,良好的吸液性保证了SiO的离子通路。25℃时在1.50-0.01 V循环,复合材料以50 m A/g充放电的首次嵌、脱锂比容量分别为1 352 m Ah/g和675 m Ah/g,库仑效率为49.9%;以200 m A/g充放电,第100次循环的可逆比容量为545 m Ah/g。
Silicon monoxide( SiO) was coated with carbon layer by the pyrolysis of polyvinyl butyral and mixed with expanded graphite( EG) to prepare SiO / C / EG composite used for Li-ion battery anode material. The electronic conductivity was increased by carbon layer. The volume expansion of SiO was restrained due to the good flexibility of EG. Meanwhile,the electronic and ionic channel was maintained,owing to the high electrolyte uptake of EG. The initial discharge specific capacity and charge specific capacity were 1 352 m Ah / g and 675 m Ah / g respectively with coulombic efficiency of 49. 9% when the composite cycled in 1. 50 -0. 01 V with 50 m A / g at 25 ℃. The reversible specific capacity was 545 m Ah / g at the 100 th cycle with 200 m A / g.