微波法制备石墨烯包覆硅材料及其性能研究∗

摘要

利用XRD、Raman、FT-IR、TEM、循环伏安、恒流充放电、交流阻抗等方法研究了微波法制备的石墨烯包覆硅材料(Si/RGO)的结构、形貌及其电化学性能.XRD、Raman、FT-IR 结果表明,微波加热能够将氧化石墨烯还原为石墨化程度较低且无序度增加的石墨烯；TEM显示石墨烯均匀包覆着纳米硅,包覆厚度大约为4 nm；充放电结果表明,石墨烯包覆硅材料具有较高的可逆比容量、良好的倍率性能和较好的循环稳定性,在400 mA/g电流密度下,首次脱锂比容量为1747 mAh/g,库伦效率为67．4％,经3次循环之后,每一循环电量转换效率均在98％以上,循环100周后,可逆的嵌脱锂比容量仍可达1175 mAh/g.%The graphene coated silicon composite (Si/RGO)was synthesized by microwave method.The struc-ture,morphology and electrochemical performances of the as-prepared samples were studied by methods of XRD,Raman,FT-IR,TEM,cyclic voltammetry,galvanostatic charge-discharge and AC impedance.The XRD,Raman and FT-IR results showed that graphene oxide was reduced tographenewith low graphitization de-gree and disordered increased.The TEM images indicated that the nano silicon was evenly coated with gra-phene,with thickness of about 4 nm.Charge and discharge results show that graphene coated silicon samples showed high specific capacity,goodrate performance and cycle stability.The initial discharge specific capacity and the coulomb efficiency was 1 747 mAh/g and 67.4%.The power conversion efficiency was increased to 98%after 3 cycles at a current density of 400 mA/g.After 100 cycles at 400 mA/g,the reversible specific capacity retained 1 1 7 5 mAh/g.