Crystal structure regulation boosts the conductivity and redox chemistry of T-Nb2O5 anode material

Abstract

T-Nb2O5 as a promising candidate anode has attracted great interest for ultrafast lithium-ion batteries (LIBs) due to its good ion conductivity and safety. However, the relatively inferior electric conductivity and low capacity greatly limit its commercial application. Herein, a trace Co doping strategy is reported to enhance the electric conductivity and redox chemistry of T-Nb2O5. The original Nb sites are partially replaced by Co, which endows Co-Nb2O5 with high electronic conductivity without affecting the crystalline host structure, meanwhile induces multielectron redoxes of Nb5+/Nb4+ and Nb4+/Nb3+ during lithium-ion insertion process. As a LIB anode, the resulting Co-Nb2O5 nanoparticles display a high discharge capacity (256.1 mAh g−1 at 0.1 A g−1), superior rate capability (141.7 mAh g−1 at 5 A g−1) and good cycling stability (179.7 mAh g−1 at 1 A g−1 after 500 cycles). The ultrafast lithium storage and high-capacity electrochemical performance of Co-Nb2O5 owing to its high electric conductivity and multielectron redox upon lithiation/delithiation. The selective transition metal doping strategy provides a new direction for the development of new insertion-type oxide anodes towards fast charging and high-capacity LIBs.