Edge-Hosted Mn-N₄-C₁₂ Site Tunes Adsorption Energy for Ultralow-Temperature and High-Capacity Solid-State Zn-Air Battery.

Abstract

Robust operation of Zn-air batteries (ZABs) with high capacity and excellent energy efficiency is desirable for practical harsh applications, whose bottlenecks are mainly originated from the sluggish oxygen catalytic kinetics and unstable Zn|electrolyte interface. In this work, we synthesized the edge-hosted Mn-N₄-C₁₂ coordination supported on N-doped defective carbon (Mn₁/NDC) catalyst, exhibiting a good bifunctional performance of the oxygen reduction/evolution reaction (ORR/OER) with a low potential gap of 0.684 V. Theoretical calculation reveals that the edge-hosted Mn-N₄-C₁₂ coordination displayed the lowest overpotential of the ORR/OER owing to the decreased adsorption free energy of OH*. The Mn₁/NDC-based aqueous ZABs deliver impressive rate performance, ultralong discharging lifespan, and excellent stability. Notably, the assembled solid-state ZABs demonstrate a high capacity of 1.29 Ah, a large critical current density of 8 mA cm^-2, and robust cycling stability with excellent energy efficiency at -40 °C, which should be attributed to the good bifunctional performance of Mn₁/NDC and anti-freezing solid-state electrolyte (SSE). Meanwhile, the zincophilic nanocomposite SSE with high polarity accounts for the stable Zn|SSE interface compatibility. This work not only highlights the importance of the atomic structure design of oxygen electrocatalysts for ultralow-temperature and high-capacity ZABs but also spurs the development of sustainable Zn-based batteries at harsh conditions.