Self-assembly Nb2O5 microsphere with hollow and carbon coated structure as high rate capability lithium-ion electrode materials

Abstract

Maintaining the high capacity of Li-ion batteries (LIBs) at the high rates is very important for electrode materials. Nb2O5 material, having high power density, is a promising high performance electrode material. However, the poor electrical conductivity and the sluggish Li-ion diffusion kinetic hinder it as anode material for LIBs. In this work, hollow Nb2O5 microsphere and carbon-coated Nb2O5 microsphere are synthesized by the solvothermal method with subsequent heat treatment in air and argon, respectively. The electrochemical tests show that the hollow Nb2O5 microsphere and the carbon-coated Nb2O5 microsphere exhibit the high reversible capacities and high rate capability. Meanwhile, due to the high specific surface area and electrical conductivity, the carbon-coated Nb2O5 microsphere shows better electrochemical performance than the hollow Nb2O5 microsphere, and has high rate capability (193 mAh g−1 and 119 mAh g−1 at the current density of 0.1 A g−1 and 5 A g−1) with the retention of 63%. This kind of novel Nb2O5 structure with high rate performance has potential as anode material for high-power LIBs.