Proton Intercalation/De‐intercalation Chemistry in Phenazine‐based Anode for Hydronium‐ion Batteries

Abstract Hydronium‐ion batteries have received significant attention owing to the merits of extraordinary sustainability and excellent rate abilities. However, achieving high‐performance hydronium‐ion batteries remains a challenge due to the inferior properties of anode materials in strong acid electrolyte. Herein, a hydronium‐ion battery is constructed which is based on a diquinoxalino [2,3‐a:2’,3’‐c] phenazine (HATN) anode and a MnO 2 @graphite felt cathode in a hybrid acidic electrolyte. The fast kinetics of hydronium‐ion insertion/extraction into HATN electrode endows the HATN//MnO 2 @GF battery with enhanced electrochemical performance. This battery exhibits an excellent rate performance (266 mAh g −1 at 0.5 A g −1 , 97 mAh g −1 at 50 A g −1 ), attractive energy density (182.1 Wh kg −1 ) and power density (31.2 kW kg −1 ), along with long‐term cycle stability. These results shed light on the development of advanced hydronium‐ion batteries.