High-performance Na2Ti2O5 nanowire arrays coated with VS2 nanosheets for sodium-ion storage

Na2Ti2O5 (NTO) nanowire arrays coated with VS2 nanosheets (NTO-VS2) have been directly prepared on a current collector as a 3D anode for Na-ion batteries. Compared to graphite, the larger interlayer spacing of two dimensional VS2 can offer facile intercalation of lithium and/or sodium ions. Aside from its natural metallic behavior, VS2 also possesses a high theoretical capacity. The composite NTO-VS2 nanowire arrays as an additive free 3D anode shows superior electrochemical performance compared to NTO. After 50 (C/10) and 100 (1C) cycles, the charge capacities of NTO-VS2 are maintained, respectively, at 298 and 203 mA h g(-1), which are much higher than the values of 157 and 93 mA h g(-1) observed for the same cycled Na2Ti2O5 electrodes. The higher capacity, improved rate capability, and good stability of the composite NTO-VS2 nanowire arrays are due to the structural stability of the Na2Ti2O5 nanowire arrays and the higher capacity and conductivity of the two-dimensional VS2 nanosheets. (C) 2015 Elsevier Ltd. All rights reserved.