Photo/electrochemical synthesis of Si@Sn microsphere composites with excellent electrochemical lithium storage

Abstract

Silicon-based anode materials with significantly improved lithium storage would play an important role in the next generation high-performance lithium-ion batteries (LIBs). Herein, a simple photo/electrochemical deposition strategy is applied to synthesize a new type of porous Si@Sn composite, using the low-cost SiAl alloy microspheres as precursor. In the dark, the galvanic replacement reaction between Si and Sn2+ induces the in-situ deposition of Sn onto the porous Si microspheres. Under light illumination, both the photogenerated electrons and the electrons from the dissolution of Si lead to the reduction from Sn2+ to Sn. The porous Si@Sn microsphere composite synthesized under the conditions of light irradiation and the optimized pH (8.0) shows excellent lithium storage performance, with a reversible capacity of 1184.4 mAh g−1 after 500 cycles at 1 A g−1 and the first coulombic efficiency of 85.19%. This may be ascribed to the integral 3D porous Si microsphere structure with the embedding of more Sn nanoparticles. This work provides an easy and efficient strategy to design and synthesize the high-performance Si-based anode materials for LIBs.