A Molecular Catalyst‐Driven Sustainable Zinc‐Air Battery Assembly

Abstract

Bidirectional oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) electrocatalysts are key for molecular oxygen‐centric renewable energy transduction via metal‐air batteries. Here, a molecular cobalt complex is covalently tethered on a strategically functionalized silica surface that displayed both ORR and OER in alkaline media. The detailed X‐ray absorbance spectroscopy (XAS) studies indicate that this catalyst retains its intrinsic molecular features while playing a central role during bidirectional electrocatalysis and demonstrating a relatively lower energy gap between O2/H2O interconversions. This robust molecular catalyst‐silica composite (deposited on a porous carbon paper) is assembled along with a zinc foil and polymeric gel membrane to devise an active single‐stack quasi‐solid zinc‐air battery (ZAB) setup. This quasi‐solid ZAB assembly displayed impressive power density (60 mW cm−2@100 mA cm−2), specific capacity (818 mAh g−1@ 5mA cm−2), energy density (757 Whkg−1 @5mA cm−2), and elongated charging/discharging life (28 h). An appropriate assembly of these ZAB units is able to power practical electronic appliances, requiring ≈1.6‐6.0V potential requirements.