Synthesis of g-C3N4-based layered silicon as an anode material for lithium-ion batteries

Abstract

The Si/g-C₃N₄ composite was prepared by a hydrothermal method using Si and g-C₃N₄ as precursors, in which Si and g-C₃N₄ were obtained from CaSi₂ and melamine, respectively. This composite was used as an anode material for Lithium ion battery, which delivered a specific capacity of 135.6 mAh.g^{– 1} at current density of 1000 mA.g^-1 and exhibited a stable cycling performance. This improvement compared to the pure Si anode is ascribed to the key role of g-C₃N₄ in relieving the structure stress induced by the large volume variation during lithiation/delithiation. Additionally, the observable enhancement in rate behavior of Si/g-C₃N₄ anode (108.8 mAh.g^-1 at current density of 5000 mA.g^-1) demonstrates the superiority of this composite in electronic and ionic conductivity which is clarified by the electrochemical impedance spectroscopy (EIS) result. This result shows g-C₃N₄ as a promising support to overcome the issue of large volume variation when using pure Si as an anode material.