Nonmetallic Nitrogen-Doped MnO₂ as Highly Efficient Oxygen Electrocatalyst for Rechargeable Zinc-Air Batteries

Zinc-air batteries (ZABs) have been considered as one of the most promising energy storage devices to solve the problem of energy crisis and environmental pollution. In this work, we reported the synthesis of nitrogen-doped MnO₂ (N-MnO₂ ) to replace the noble metal electrocatalysts for air cathode in ZABs. The doped N atoms here introduced more Mn³⁺ and oxygen vacancies for MnO₂ , enhancing charge transfer property and accelerating surface intermediate product during the oxygen reduction reaction (ORR). Hence, the best N-MnO₂ achieved remarkable electrocatalytic activities towards ORR (half-wave potential of 0.797 V vs. RHE), and reversible oxygen overpotential of around 0.842 V, which is better than or comparable to the Pt/C and Mn-based catalysts reported recently. Moreover, the homemade ZABs based on N-MnO₂ showed the maximum power density of 132.8 mW cm^-2 and excellent cyclic stability.