Two-dimensional Porous Sandwich-like C/Si-Graphene-Si/C Nanosheets for Superior Lithium Storage

By Yao, Weiqi; Chen, Jie; Zhan, Liang; Wang, Yanli; Yang, Shubin
Published in ACS Applied Materials & Interfaces

Abstract

A novel two-dimensional porous sandwich-like Si/carbon nanosheets are designed and successfully fabricated as anode for superior lithium storage, where porous Si nanofilm grows on the two sides of reduced grahene oxide (rGO) and then coated with a carbon layer (denoted as C/Si-rGO-Si/C). The coexistence of micropores and mesopores in C/Si-rGO-Si/C nanosheets offer a rapid Li+ diffusion rate, and the porous Si provides a short pathway for electric transportation. Meanwhile, the coated carbon layer not only can promote to form stable SEI layer, but also can improve the electric conductivity of nanoscale Si coupled with rGO. Thus, the unique nanostructures offer the resultant C/Si-rGO-Si/C electrode with a high reversible specific capacity (1187 mAh g-1 after 200 cycles at 0.2 A g-1) , excellent cyclic stability (894 mAh g-1 after 1000 cycles at 1 A g-1) and high rate capability (694 mAh g-1 at 5 A g-1 and 447 mAh g-1 at 10 A g-1 ).

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