Synthesis of Robust Silicon Nanoparticles@Void@Graphitic Carbon Spheres for High-Performance Lithium-Ion-Battery Anodes

Silicon is known to be a promising candidate anode material for lithium-ion batteries because of its ultrahigh capacity; however, its volume expansion/shrinkage during lithiation/delithiation reactions represent the biggest challenge in practical applications. In this paper, we successfully design and synthesize a new type of robust silicon nanoparticles@void@graphitic carbon spheres (Si@void@C) material to buffer the silicon volume changes in the cyclic lithiation/delithiation process. The as-obtained Si@void@C nanocomposite spheres with well-dispersed silicon nanoparticles, efficient void spaces, and graphitic carbon shells can endow this nanocomposite anode with the robustness to solve the volume expansion/shrinkage issue. As demonstrated by coin battery performances, the Si@void@C nanocomposite sphere-based anode exhibits a specific capacity retention of 1565 and 1260 mAhg(-1) at C/5 and C/2 (1C=4200 mAg(-1)), respectively, after 1000 cycles of deep charge/discharge processes (voltage between 0.01 and 2.7 V versus Li/Li+). It provides a promising anode for a safe and high-performance Si-based materials in high-performance lithium-ion batteries.