High Electrocatalytic Activity of Silver-Doped Manganese Dioxide toward Oxygen Reduction Reaction in Aluminum-Air Battery

The development of the efficient and economical catalysts for the oxygen reduction reaction (ORR) is an important issue for the commercialization of metal-air batteries. Herein, a silver-doped δ-MnO2 dispersed on carbon powder (Ag-MnO2/C) was synthesized by a facile route. The specific surface area of Ag-MnO2/C is more than three times higher than that of MnO2/C. Moreover, Ag-MnO2/C shows much higher catalytic activity toward ORR than MnO2/C or Ag/C. The half-wave potential of Ag-MnO2/C is much more positive compared with that of 20% Pt/C. Ag-MnO2/C also exhibits an excellent long-term stability and the ORR current retention keeps 97.1% after aging for 45000 s. Using Ag-MnO2/C as the ORR catalyst, the peak power density of Al-air battery reaches 315 mW cm−2 which is almost the highest record.