A Hybrid Na//K^(+)-Containing Electrolyte//O_(2) Battery with High Rechargeability and Cycle Stability

Na-O_(2) and K-O_(2) batteries have attracted extensive attention in recent years.However,the parasitic reactions involving the discharge product of NaO_(2) or K anode with electrolytes and the severe Na or K dendrites plague their rechargeability and cycle stability.Herein,we report a hybrid Na//K^(+)-containing electrolyte//O_(2) battery consisting of a Na anode,1.0 M of potassium trifate in diglyme,and a porous carbon cathode.Upon discharging,KO_(2) is preferentially produced via oxygen reduction in the cathode with Na+stripped from the Na anode,and reversely,the KO_(2) is electrochemically decomposed with Na+plated back onto the anode.Te new reaction pathway can circumvent the parasitic reactions involving instable NaO_(2) and active K anode,and alternatively,the good stability and conductivity of KO_(2) and stable Na stripping/plating in the presence of K^(+) enable the hybrid battery to exhibit an average discharge/charge voltage gap of 0.15 V,high Coulombic efciency of>96%,and superior cycling stability of 120 cycles.Tis will pave a new pathway to promote metal-air batteries.