Abstract
As concerns about the availability of mineral resources for lithium-ion batteries (LIBs) arise and demands for large-scale energy storage systems rapidly increase, non-LIB technologies have been extensively explored as low-cost alternatives. Among the various candidates, sodium-ion batteries (SIBs) have been the most widely studied, as they avoid the use of expensive and less abundant elements such as lithium, cobalt, and nickel while also sharing similar operating principles with LIBs. In this Perspective, we discuss why SIBs hold great promise and can act as competitors to lithium-ion technology. In addition, the remaining challenges and future research directions are highlighted, focusing on cathode developments and the use of SIBs in large-scale applications, including electric vehicles and stationary energy storage.