High-performance characteristics of silicon inverse opal synthesized by the simple magnesium reduction as anodes for lithium-ion batteries

Inverse silicon opal (ISi) and carbon-coated inverse Si opal (C-ISi) structures are prepared from the simple thermal reduction method using magnesium and investigated as the anode materials in lithium-ion batteries. The ISi and C-ISi samples comprise continuously arranged inverse opal structures, constructed by Si nanoparticles. The macroporous structures in similar to 1 gm range are favourable for lithium-ion transport and more importantly for absorbing volumetric change in the silicon nanoparticles. Moreover, the carbon coating on the inverse Si opal improves the electrical conductivity and acts as a mechanical buffer for the volume change. C-ISi sample shows a high capacity of 1550 mAh g(-1) at the 100th cycle with very stable cycle retention, whereas the ISi and pristine Si samples show 1146.4 mAh g(-1) and approximately zero, respectively, at the 100th cycle with rapid capacity fading. Surprisingly, the volumetric expansion of C-ISi electrode after 100th cycles is only 16.1%, which is as low as that for commercial graphite electrodes. (C) 2015 Elsevier B.V. All rights reserved.