Electrospun-based nanofibers for sodium and potassium ion storage: Structure design for alkali metal ions with large radius

Sodium and potassium ion storage have received more attention over the last several years due to their fascinating properties, such as competitive cost-benefit and sustainable resource supply. It is challenging to maintain a stable electrode structure during the electrochemical process for the larger radius ions of Na+ and K+. One-dimensional (1D) materials can be an ideal model for developing insight into relationships between physical-chemical properties and dimension when used as electrodes. Furthermore, it can serve as a convenient migration pathway for electrons or ions, enhancing charge transfer and reducing contact resistance. As a controllable and facile synthesis approach, electrospun can be applied to design 1D nanofibers with tunable compositions and morphologies to supply the required high electrochemical activity and stability. In this review, we will discuss current electrospun techniques used to make stable electrodes for larger radius ions and enhance electrochemical stability. Some approaches to promote the thermal stability and mechanical strength of separators through electrospun strategies are also included. The insights presented in this article can serve as a guide for fabricating electrospun-based nanofiber electrodes for larger radius ion storage.