Additive-free sodium titanate nanotube array as advanced electrode for sodium ion batteries

Low cycling stability and poor rate performance are two of the distinctive drawbacks of most electrode materials for sodium (Na) ion batteries due to the large size of the Na ions. The TiO6 octahedrons interconnect with each other by edges or corners to form both layer- and tunnel-structured sodium titanates (NTO). Such open structures make NTO promising anode materials for sodium (Na) ion batteries. Herein, (conduction and binder) additive-free NTO nanotube array chemically engraved on a Ti foil is used as an electrode and exhibits outstanding rate performance and long-term cycling stability. When a current density of 3200 mA g(-1) (i.e., one complete cycle in one minute) is applied, the array delivers a reversible capacity of 42 mAh g(-1). Even after 5000 galvanostatic (400 mA g(-1)) cycles, the electrode retains a capacity of 55 mAh g(-1). These excellent performances are attributed to the open structure and the nano-architecture of the NTO nanotube arrays. (C) 2015 Elsevier Ltd. All rights reserved.