Layered MNb3O8 (M=H, Li, Na, K) driven by intercalation pseudo-capacitor for lithium battery anode material

Abstract

Niobium-based materials have always been regarded as outstanding anode materials due to its capability of multiple electron transfer. Here, layered polyniobate MNb3O8 (M=H, Li, Na) was prepared by ion-exchange of precursors KNb3O8. HNb3O8 present an excellent charge/discharge capacity of 394.1 mAh g−1/426.8 mAh g−1 at 0.1 C and the Coulombic efficiency is 91.99% after fifth cycle. Even after 60 cycles, it still retains substantial discharge specific capacities of 148.7 mAh g−1 at 0.5 C. In addition, by employing technics including XRD, Raman and XPS, HNb3O8 are demonstrated to possess a larger interlayer channel of 1.11 nm and a stronger binding energy to foreign electrons than MNb3O8 (M=K, Li, Na). This properties could justify the best electrochemical performance of HNb3O8. EIS analysis also reveal that HNb3O8 has the smallest charge transfer impedance among all the samples. All these advantages suggest that HNb3O8 can be an alternative anode material for next generation lithium-ion batteries (LIBs).