Enhancing niobium-based oxides for high-performance lithium-ion batteries through hydrogenation.

Niobium-based oxides (NMO) have attracted widespread research enthusiasm in the field of energy storage systems, including lithium-ion batteries (LIBs). Most recently, MoNb12O33 was reported as a promising material for LIBs due to its long-term cyclability, high theoretical/practical capacities, safe operating potential, and excellent structural stability. Nevertheless, the kinetics of electrochemical reactions in MoNb12O33 is hindered by its intrinsically poor electronic conductivity and electron transfer properties. These tend to be significant flaws restricting its practical use in LIBs. In this study, we employed an electrospinning technique and subsequent hydrogenation treatment for fabricating NMO and NMO@H-Ar (@H-Ar denotes heat treatment under hydrogen and argon mixture) nanowires. The hydrogenation treatment narrows the band gap, expands unit cell volume, and creates oxygen vacancies in NMO@H-Ar. These resulted in outstanding electrochemical kinetics in the NMO@H-Ar anode, including a high reversible specific capacity of 327 mAh g−1 at 0.1 C, high initial coulombic efficiency of 92.4%, excellent long-term cycling stability with capacity retention of 94.4% (capacity loss per cycle of 0.0056%) after 1000 cycles at 10 C, and good rate performance of 179.7 mAh g−1 at 10 C. In addition, the data obtained from the electrochemical impedance and cyclic voltammetry tests confirm that the hydrogenation treatment significantly enhanced the electronic conductivity and lithium-ion diffusion coefficient. This study affirms that the hydrogenation treatment considerably improved the electronic conductivity and electrochemical reactions kinetics of NMO@H-Ar nanowires, which is beneficial for developing new anode materials for LIBs. [ABSTRACT FROM AUTHOR]