Facile and Efficient Fabrication of Branched Si@C Anode with Superior Electrochemical Performance in LIBs.

Abstract

One-dimensional Si nanostructures with carbon coating (1D Si@C) show great potential in lithium ion batteries (LIBs) due to small volume expansion and efficient electron transport. However, 1D Si@C anode with large area capacity still suffers from limited cycling stability. Herein, a novel branched Si architecture is fabricated through laser processing and dealloying. The branched Si, composed of both primary and interspaced secondary dendrites with diameters under 100nm, leads to improved area capacity and cycling stability. By coating a carbon layer, the branched Si@C anode shows gravimetric capacity of 3059 mAh g-1 (1.14 mAh cm-2 ). At a higher rate of 3 C, the capacity is 813 mAh g-1 , which retained 759 mAh g-1 after 1000 cycles at 1 C. The area capacity is further improved to 1.93 mAh cm-2 and remained over 92% after 100 cycles with a mass loading of 0.78mg cm-2 . Furthermore, the full-cell configuration exhibits energy density of 405Wh kg-1 and capacity retention of 91% after 200 cycles. The present study demonstrates that laser-produced dendritic microstructure plays a critical role in the fabrication of the branched Si and the proposed method provides new insights into the fabrication of Si nanostructures with facility and efficiency.