GaNb₁₁O₂₉ Nanowebs as High-Performance Anode Materials for Lithium-Ion Batteries

Abstract

M–Nb–O compounds have been considered as promising anode materials for lithium-ion batteries (LIBs) because of their high capacities, safety, and cyclic stability. However, very limited M–Nb–O anode materials have been developed thus far. Herein, GaNb₁₁O₂₉ with a shear ReO₃ crystal structure and a high theoretical capacity of 379 mAh g^–1 is intensively explored as a new member in the M–Nb–O family. GaNb₁₁O₂₉ nanowebs (GaNb₁₁O₂₉-N) are synthesized based on a facile single-spinneret electrospinning technique for the first time and are constructed by interconnected GaNb₁₁O₂₉ nanowires with an average diameter of ∼250 nm and a large specific surface area of 10.26 m² g^–1. This intriguing architecture affords good structural stability, restricted self-aggregation, a large electrochemical reaction area, and fast electron/Li⁺-ion transport, leading to a significant pseudocapacitive behavior and outstanding electrochemical properties of GaNb₁₁O₂₉–N. At 0.1 C, it shows a high specific capacity (264 mAh g^–1) with a safe working potential (1.69 V vs Li/Li⁺) and the highest first-cycle Coulombic efficiency in all of the known M–Nb–O anode materials (96.5%). At 10 C, it exhibits a superior rate capability (a high capacity of 175 mAh g^–1) and a durable cyclic stability (a high capacity retention of 87.4% after 1000 cycles). These impressive results indicate that GaNb₁₁O₂₉-N is a high-performance anode material for LIBs