Preparation of porous silicon by Ag-assisted chemical etching in non-filling type carbon shell for high performance lithium-ion batteries

Abstract

Silicon is regarded as one of the most potential anode materials due to its high specific capacity (4200 mAh g−1), but some disadvantages such as low conductivity and large volume expansion effect cannot be ignored. Here, a silver etched and non-filling type carbon coating porous silicon (pSi/Ag@C) anode material is proposed to solve the problems. The porous structure can alleviate the volume change of the silicon material during charging and discharging process. It is worth mentioning that, compared with the traditional carbon coating, the novel non-filled carbon coating layer reserves space for the volume expansion of silicon, which can prevent the rupture of carbon layer. The pSi/Ag@C anode material maintains a high discharge specific capacity of 904 mAh g−1 after 200 cycles at a current density of 0.5 C (1 C = 4.2 A g−1), much better than the 333.1 mAh g−1 of Si-raw material.