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

Abstract

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 MnO 2 (N-MnO 2 ) to replace the noble metal electrocatalysts for air cathode in ZABs. The doped N atoms here introduced more Mn 3 + and oxygen vacancies for MnO 2 , enhancing charge transfer property and accelerating surface intermediate product during the oxygen reduction reaction (ORR). Hence, the best N-MnO 2 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-MnO 2 showed the maximum power density of 132.8 mW cm À 2 and excellent cyclic stability.

Ammonium ion intercalation and oxygen-rich vacancies in birnessite-type MnO2 for supercapacitors and oxygen evolution applications

“…It was the feature peak of interstitial N, which proved that the N atoms successfully entered the interior of the MnO 2 lattice. 56,60 The characteristic peak at around 401.67 eV belonged to NH 4 + ions with electrostatic interactions between the MnO 2 layers. 34 NH 4 + ions doping increased the amount of oxygen vacancies in the material, which was beneficial for increasing the electron transport rate and improve the electrical conductivity of the material.…”