Bridging Molecular Precision and Device Functionality With Triazole Based Cobalt Catalyst for Cross-Platform Rechargeable Metal-Air Batteries.

Rechargeable metal-air batteries offer exceptional theoretical energy densities but require durable bifunctional electrocatalysts that efficiently mediate oxygen reduction (ORR) and oxygen evolution (OER). Here, a triazole-based cobalt complex (CoTzN) is developed to bridge molecular-level mechanistic understanding with practical device integration. In homogeneous media, CoTzN catalyzes bidirectional ORR/OER, while electrochemical and spectroelectrochemical studies identify key Co(III)-OOH and Co(III)-O• intermediates. These molecular insights guide catalyst heterogenization on carbon nanotubes through π-π interactions (CoTzN-P) and covalent amide anchoring (CoTzN-C). CoTzN-C exhibits enhanced charge transfer, stability across pH 7-14, and a highly selective four-electron ORR pathway (n ≈ 3.95) with <5% H2O2 production. Extended electrolysis demonstrates robust bifunctional activity with Faradaic efficiencies of ≈91% for ORR and ≈89% for OER. Importantly, CoTzN-C functions as a bifunctional air cathode across two distinct rechargeable metal-air battery platforms. A quasi-solid-state Zn-air battery sustains >450 rapid charge-discharge cycles over ≈30 h, while a non-aqueous Li-air battery operates for 80 prolonged cycles (≈160 h). This molecular-to-device framework demonstrates how coordination-level catalyst design can be translated into robust hybrid electrodes for cross-platform rechargeable metal-air batteries.