Self-Assembly of Hierarchical Silicon Suboxide Nanoparticles Encapsulated in Nitrogen-Doped Carbon as High Performance Anode Material for Lithium-Ion Batteries

The application of SiOx/C composites as ideal anode materials to replace the current commercial graphite is hindered by their huge volume change, low electrical conductivity, costly raw materials, and rigorous synthetic procedure in lithium-ion batteries. In this work, we successfully take the advantage of self-assembly method to prepare hierarchical silicon suboxide nanoparticles/nitrogen-doped carbon (H-SiOx/NC) composite for the first time, in which the H-SiOx core and the in situ formed NC shell not only buffer the dramatic volume change of H-SiOx nanoparticles during cycles, but also effectively improve the electrical conductivity of the H-SiOx/NC composite. The H-SiOx/NC electrode delivers an initial reversible capacity of 842.8 mA h g−1 at 0.1A g−1, an excellent capacity retention of 93.6% after 100 cycles, and respectable rate capability of 327 mA h g−1 at 2 A g−1. After thermal stability test, the H-SiOx/NC electrode shows intact with reasonably slight cracks. In addition to the excellent electrochemical performance, the low-cost raw materials and high-yield processing make the H-SiOx/NC composite attractive anode candidate for Lithium-ion battery.