First-principles calculations and experimental study of Mo-doped porous nano-silicon anodes for Li-ion batteries

Abstract

The poor electronic conductivity and inherent volume expansion pose challenges for Silicon (Si) to be commercialized. Herein, we investigate the influence of Mo-dopant on the electronic structure and crystal structure of Si using first-principle calculations. The results show that Mo-doping can expand the crystal lattice and reduce the bandgap of Si, which improves its intrinsic conductivity. Furthermore, Mo-doped porous nanostructured Si (Mo-PNSi) were first prepared through a hydrothermal method and magnesiothermic reduction. As a result, the obtained Mo-PNSi anodes depict a high specific capacity of 2197.7 mAh g−1 at a current density of 0.84 A g−1 and a high capacity retaining of nearly 100% from 30 to 200 cycles. In particular, Mo-PNSi anodes display superior cycling stability of 911.5 mAh g−1 after 1000 cycles at a current density of 4.2 A g−1. Even at a high rate of 6.72 A g−1, a specific capacity of 840.1 mAh g−1 can be delivered.