In Situ Formation of Lattice‐Distorted Mn‐Based Catalysts Boosting High Energy‐Efficiency Aqueous Metal‐Air Batteries

Rechargeable aqueous metal-air batteries (AMABs) offer sustainable energy storage solutions with inherent safety, cost-effectiveness, and high theoretical energy density. However, their practical performance is limited by sluggish oxygen redox kinetics, especially in CO₂-tolerant and anode-friendly near-neutral electrolytes. Here, a feasible catalyst design strategy is reported by introducing Mn²⁺ into aqueous electrolytes to enable in situ formation of MnO₂. Notably, this electrodeposited MnO₂ exhibits a unique 3% lattice contraction, which upshifts the d-band center and significantly accelerates oxygen evolution reactions. The lattice distortion optimizes the ^*OOH intermediate formation energy, reducing the potential-determining step barrier by ≈17.0% compared to conventional MnO₂. Consequently, Zn-air batteries with near-neutral electrolytes achieve a 35.9% reduction in OER/ORR overpotential (0.50 V) and elongated cycling stability (>1000 h). This approach further enables Mn-air batteries to achieve a low overpotential (0.29 V) and high energy efficiency (84.2%), offering a universal strategy for efficient, durable, and CO₂-tolerant AMABs.