Challenges and Applications of Flexible Sodium Ion Batteries

Sodium-ion batteries are considered to be a future alternative to lithium-ion batteries because of their low cost and abundant resources. In recent years, the research of sodium-ion batteries in flexible energy storage systems has attracted widespread attention. However, most of the current research on flexible sodium ion batteries is mainly focused on the preparation of flexible electrode materials. In this paper, the challenges faced in the preparation of flexible electrode materials for sodium ion batteries and the evaluation of device flexibility is summarized. Several important parameters including cycle-calendar life, energy/power density, safety, flexible, biocompatibility and multifunctional intergration of current flexible sodium ion batteries will be described mainly from the application point of view. Finally, the promising current applications of flexible sodium ion batteries are summarized.