Abstract
? 2022 Elsevier B.V.Niobium pentoxide (Nb2O5) anodes have attracted much attention as a candidate for the next generation lithium-ion batteries (LIBs) due to the unique physical and chemical properties. However, some critical issues, like low electronic conductivity, inefficient ionic diffusion, must be addressed before practical applications. In this work, we employed a facile NaBH4 engaged chemical reduction method to modify Nb2O5 anodes. Microstructure and surface chemistry analysis indicated that the Nb2O5 materials have micro/nanoscale three-dimensionally interconnected morphology, and contain three different phases (T-, M-, and H-Nb2O5). More importantly, oxygen vacancies are introduced by the NaBH4 reduction treatment, and the oxygen vacancy amount can be modulated by changing the NaBH4 concentration. As anodes for LIBs, the optimized sample exhibited a reversible capacity of 252.2 mAh·g?1 after 100 cycles at a current density of 1 C, and a reversible capacity of 139.4 mAh·g?1 at a large current density of 10 C. The electrochemical performance enhancement can be attributed to the combination of multiscale structural design, i.e., oxygen vacancy, nanoscale phase interface, and micro/nanoscale three-dimension assembly. We expect the present synergistic strategy can be employed to manipulate the key structures in different functional materials for broader applications.
NSTL
Elsevier