Flexible fiber-shaped sodium-ion battery based on self-supported sulfur-doped TiO2 nanotube arrays

Fiber-shaped rechargeable batteries are expected to be the energy storage device as a necessary part of the next generation of wearable electronics. However, their application is severely hindered by the difficulty in manufacture of flexible fiber-shaped electrodes with promising electrochemical performance. Here, we fabricated the unique self-supporting nanotube array of sulfur-doped TiO2 (S TiO2) to obtain flexible fiber-shaped electrode with excellent sodium storage properties. The as-prepared S TiO2 fiber electrode has a high reversible capacity of about 183 mA h g−1 at 40 mA g−1, excellent rate capability (142 mA h g−1 at 80 mA g−1) and stable cycling performance (75% retention over 100 cycles at 80 mA g−1). It is worth noting that a flexible fiber-shaped sodium-ion battery was maintained a high reversible capacity under different bending states. This work offers a novel electrode-fabrication method towards broadenning metallic oxide fiber electrodes application especailly in flexible energy storage devices.