Nickel‐Nitrogen Doped MnO2 as Oxygen Reduction Reaction Catalyst for Aluminum Air Batteries

Aluminum‐air battery has the advantages of high energy density, low cost and environmental protection, and is considered as an ideal next‐generation energy storage conversion system. However, the slow oxygen reduction reaction (ORR) in air cathode leads to its unsatisfactory performance. Here, we report an electrode made of N and Ni co‐doped MnO2 nanotubes. In alkaline solution, Ni/N‐MnO2 has higher oxygen reduction activity than undoped MnO2, with an initial potential of 1.00 V and a half‐wave potential of 0.75 V. This is because it has abundant defects, high specific surface area and sufficient Mn3+ active sites, which promote the transfer of electrons and oxygen‐containing intermediates. Density functional theory (DFT) calculations show that MnO2 doped with N and Ni atoms reduces the reaction overpotential and improves the ORR kinetics. The peak power density and energy density of the Ni/N‐MnO2 air electrode increased by 34.03 mW·cm‐2 and 316.41 mWh·g‐1, respectively. The results show that N and Ni co‐doped MnO2 nanotubes are a promising air electrode, which can provide some ideas for the research of aluminum‐air batteries.