Large-scale synthesis of Si@C three-dimensional porous structures as high-performance anode materials for lithium-ion batteries

Abstract

We demonstrate the synthesis of Si@C three-dimensional porous structures derived from commercial magnesium silicide (Mg₂Si) powder via simple annealing and acid pickling processes. When used as anode materials in lithium-ion batteries, the Si@C three-dimensional porous structures can give more lithiation sites and accommodate large volume changes during the lithiation/delithiation process, which leads to a high capacity and good cycling stability. As a result, a high reversible capacity of ∼1700 mA h g⁻¹ was obtained at a current of 0.2 C (800 mA g⁻¹, 1 C = 4 A g⁻¹) even after 70 cycles. The synthetic route described herein is a low-cost and large-scale method to produce high-performance Si anodes, which may facilitate their commercial applications.