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, Ti2Nb10O29 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, Cr3+-Nb5+ co-doping and carbon nanotube (CNT) compositing is employed. A novel TiCr0.5Nb10.5O29/CNTs nanocomposite with 9.1 wt% CNTs is fabricated by a direct hydrolysis process followed by calcination in N-2. The Cr3+-Nb5+ co-doping significantly improves the electronic conductivity and Li+-ion diffusion coefficient of Ti2Nb10O29 by three orders and one order of magnitude, respectively. The CNT compositing not only enhances the electrical conduction among the TiCr0.5Nb10.5O29 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 TiCr0.5Nb10.5O29/CNTs nanocomposite exhibits a high rate capability with a high capacity of 206 mAh g(-1) at 20 C, surpassing those of Ti2Nb10O29 (145 mAh g(-1)) and TiCr0.5Nb10.5O29 nanoparticles (187 mAh g(-1)). Additionally, TiCr0.5Nb10.5O29/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 TiCr0.5Nb10.5O29/CNTs can be an advanced anode material for high-performance Li+-ion storage. (c) 2017 Elsevier B.V. All rights reserved.