Recent Progress of Emerging Cathode Materials for Sodium Ion Batteries

Recently, due to the excessive consumption of fossil energy and the intermittent nature of clean energy resources, the electricity storage has attracted great attention from both academia and industry. Lithium ion batteries (LIBs) with high energy density have been widely used for portable energy storage systems. However, the limited lithium resources cannot meet the demands for large-scale applications, especially the grid-scale energy storage. Owing to the abundant natural resources of sodium and low price, sodium ion batteries (SIBs) become potential substitutes for LIBs. Cathode materials are the key component which determine the overall performance and entire cost of SIBs. However, the unstable structure and limited electrochemical performance make them difficult to meet the requirement of practical applications. This review summarizes the recent development of the cathode materials used for SIBs and the modified strategies applied to improve their electrochemical performance. Finally, the critical challenges and the perspectives forward to promote the development of SIBs are presented as well.