First-principles calculations insight into non-noble-metal bifunctional electrocatalysts for zinc–air batteries

Zinc–air batteries (ZABs) have triggered a research boom in energy storage technologies due to their low cost, high safety and environmental friendliness. The slower kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air-electrode of ZABs have led to an increasing demand for improving the performance of air-electrode electrocatalysts. First-principles calculations explain the properties and behaviors of electrocatalyst materials and catalytic mechanisms at the atomic scale and provide rational design strategies for cathodic electrocatalyst materials, which makes it has become a powerful technique for developing efficient new electrocatalysts. We present an overview of first-principles calculations methods and emphasize their important role in the contemporary study of air-electrode electrocatalyst materials for ZABs. Firstly, the electronic structure of the air-electrode electrocatalyst, the interface effect of the air-electrode | electrolyte with the diffusion of oxygen and water molecules, and the catalytic reaction mechanism are systematically summarized, and some representative examples are presented. Emphasis is placed on several aspects such as the d-band center of the transition metal, the dynamic behavior of the diffusion of oxygen and water molecules, and the Gibbs free energy of the ORR/OER process. The way in which theoretical calculations support experiments is also explored. Finally, the challenges and prospects for development of first-principles calculations applied to ZABs are discussed from a personal perspective.