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

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 MnO₂ @graphite felt cathode in a hybrid acidic electrolyte. The fast kinetics of hydronium-ion insertion/extraction into HATN electrode endows the HATN//MnO₂ @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.