A three-dimensional porous Si/SiOx decorated by nitrogen-doped carbon as anode materials for lithium-ion batteries

Nano-sized Si-based materials have been proposed as one of the most promising anodes of lithium-ion batteries (LIBs) due to their advantageous capacity. However, the widespread use of nano-sized Si-based material is still limited by their high cost, large volume expansion, and intrinsically low conductivity. Here, we demonstrate the decoration of three-dimensional porous Si/SiOx with nitrogen-doped carbon composites via a hydrothermal and megnesiothermic reduction. The as-prepared composites deliver a high reversible capacity of 1082 mAh g−1 after 200 cycles at a current density of 200 mA g−1. The rate performance of the composites was evaluated from 100 to 1000 mA g−1, even at a high current density of 1000 mA g−1, the reversible specific capacity remained at 510 mAh g−1. The good electrochemical performance of the composites may be ascribed to the three-dimensional porous structure, which relieves the volume changes of Si/SiOx during lithiation/delithiation processes. In addition, the introduced nitrogen-doped carbon can offer additional active sites for storage capacity and increase the electrical conductivity. Therefore, this work provides a promising anode for high-energy-density LIBs.