Sodium-ion conducting polymer electrolytes

Almost unlimited reserves and low cost of sodium are accelerating the commercialization of sodium-ion batteries. However, serious safety and stability issues, arising mainly from organic liquid electrolytes, hinder further developments of sodium-ion batteries. Polymer electrolytes might be a solution to the safety and stability issues due to the better safety of polymers. Herein, an overview is provided on recent advances in polymer electrolytes for solid-state sodium batteries, including solid polymer electrolytes, composite polymer electrolytes and gel polymer electrolytes. Fundamental properties, ionic conduction mechanisms and promising applications of polymer electrolytes are discussed, and pending challenges and effective solutions are emphasized. Hopefully, this review will promote commercial applications of polymer electrolytes in energy storage systems. Graphical abstract