Long-Cycle-Life Cathode Materials for Sodium-Ion Batteries toward Large-Scale Energy Storage Systems

The development of large-scale energy storage systems (ESSs) aimed at application in renewable electricity sources and in smart grids is expected to address energy shortage and environmental issues. Sodium-ion batteries (SIBs) exhibit remarkable potential for large-scale ESSs because of the high richness and accessibility of sodium reserves. Using low-cost and abundant elements in cathodes with long cycling stability is preferable for lowering expenses on cathodes. Many investigated cathodes for SIBs are dogged by structural and morphology changes, unstable interphases between the cathode and the electrolyte, and air sensitivity, causing unsatisfactory cycling performance. Therefore, understanding the mechanism of capacity degeneration in depth and developing precise solutions are critical for designing low-cost cathodes that are highly stable under cycling. Herein, recent progress in long-cycle-life and low-cost cathodes for SIBs is focused on, and a comprehensive discussion of the key points in SIBs toward large-scale applications is provided. The roots of the unstable cycling performance of low-cost cathodes are discussed. Also, effective strategies are summarized from the recent progress on long-cycle-life and low-cost cathodes. This review is expected to encourage deeper investigation of long-lifespan cathodes for SIBs, particularly for potential large-scale industrialization.