N-SiOx/graphite/rGO-CNTs@C composite with dense structure for high performance lithium-ion battery anode

Abstract

SiOx has become one of the most promising anode materials for lithium ion batteries due to its high specific capacity, abundant natural resources and suitable lithium insertion and extraction voltage. However, the low conductivity and the poor cycle performance seriously hinder its practical application. In here, a simple and effective method is proposed to disperse SiOx between carbon materials including flake graphite, reduced graphene oxide (rGO) and carbon nanotubes (CNTs), and then micron-sized N-SiOx/graphite/rGO-CNTs@C (N-SiOx/C@C) composite with dense structure is prepared by coating and pyrolysis of pitch. The synergistic effect of various carbon materials is beneficial to improve the conductivity of the material, and maintain the structural integrity during the cycle. The obtained N-SiOx/C@C anode exhibits high reversible capacity (980.2 mAh·g−1), excellent cycle stability (70 % capacity retention after 500 cycles at 0.5 A·g−1) and excellent rate performance (491.9 mAh·g−1 specific capacity of at 5 A·g−1). The strategy provided here effectively improves the electrochemical performances of SiOx, and the prepared materials show great application potential in the field of lithium ion batteries.