Pseudohexagonal Nb2O5-Decorated Carbon Nanotubes as a High-Performance Composite Anode for Sodium Ion Batteries

Abstract

To promote the commercial application of sodium ion batteries (SIBs), new high-stability and high-capacity anode materials are needed. Metal oxides show great promise, but significant issues relating to their low electrical conductivity and unstable structure during charge storage must be resolved. Herein, a new composite anode consisting of pseudohexagonal Nb2O5 (TT-Nb2O5) nanoparticles strongly anchored to carbon nanotubes (CNT) through a glucose-derived carbon framework (Nb2O5/g-CNT) was synthesised and assessed for use as the anode in SIBs. This represents the first application of TT-Nb2O5 in SIBs. The composite is shown to offer high specific capacity (203 mAh g−1 at 0.2 A g−1), good rate capability (53 mAh g−1 at high current density of 5 A g−1), and a high-capacity retention rate (135 mAh g−1 at 0.2 A g−1 between 25 and 300 cycles). This is attributed to high electrical conductivity and flexibility offered by the designed carbon framework, the superior capacity of the TT-Nb2O5 and the linkage between the two provided by the bonding glucose derived carbon. This work therefore demonstrates a scalable route for the application of metal oxides in future high-performance SIB systems.