TiCr0.5Nb10.5O29/CNTs nanocomposite as an advanced anode material for high-performance Li+-ion storage

As a recently developed anode material for lithium-ion batteries, Ti 2 Nb 10 O 29 shows high theoretical/practical capacities and safety, but suffers from a poor rate capability due to its insulator nature and insufficient Li + -ion diffusion coefficient . To tackle this issue, a strategy combining nanosizing, Cr 3+ –Nb 5+ co-doping and carbon nanotube (CNT) compositing is employed. A novel TiCr 0.5 Nb 10.5 O 29 /CNTs nanocomposite with 9.1 wt% CNTs is fabricated by a direct hydrolysis process followed by calcination in N 2 . The Cr 3+ –Nb 5+ co-doping significantly improves the electronic conductivity and Li + -ion diffusion coefficient of Ti 2 Nb 10 O 29 by three orders and one order of magnitude, respectively. The CNT compositing not only enhances the electrical conduction among the TiCr 0.5 Nb 10.5 O 29 particles but also hinders the particle growth in the hydrolysis process, leading to the small particle sizes. Due to the synergistic effect of these advantages, the TiCr 0.5 Nb 10.5 O 29 /CNTs nanocomposite exhibits a high rate capability with a high capacity of 206 mAh g −1 at 20 C, surpassing those of Ti 2 Nb 10 O 29 (145 mAh g −1 ) and TiCr 0.5 Nb 10.5 O 29 nanoparticles (187 mAh g −1 ). Additionally, TiCr 0.5 Nb 10.5 O 29 /CNTs delivers a high reversible capacity (297 mAh g −1 at 0.1 C) and cyclic stability (95.0% capacity retention after 100 cycles at 10 C). This good electrochemical performance reveals that TiCr 0.5 Nb 10.5 O 29 /CNTs can be an advanced anode material for high-performance Li + -ion storage.