Powering the Future : A Cobalt-Based Catalyst for Longer-Lasting Zinc–Air Batteries

The development of cost-effective catalysts for zinc–air batteries (ZABs) remain challenging due to the sluggish kinetics of oxygen reduction (ORR) and evolution (OER) at the cathode. In this context, a novel N-doped graphitic shell-encapsulated cobalt catalyst is presented as an air electrode with exceptional bifunctional activity, achieving an ORR half-wave potential (E1/2) of 0.81 V and an OER overpotential of 349 mV in an alkaline medium. The catalyst demonstrated excellent cycling durability and delivered superior power density in both liquid and solid-state ZABs. Furthermore, a quasi-solid-state ZAB is assembled with the catalyst, and it maintained a stable open-circuit voltage (OCV) of 1.360 V for >10 000 s. The catalyst achieved a peak power density of 127 mW cm−2—significantly outperforming the benchmark Pt/C + RuO2 system (74 mW cm−2). When two tandem-junction ZABs are connected in series, they achieved an OCV of 2.75 V and powering a “ZAB” LED strip and a mini fan. Furthermore, Density Functional Theory (DFT) calculations revealed that the enhanced performance resulted from optimized binding energies between the Co@N(py) active sites and reaction intermediates. An in situ Raman study is carried out to understand the catalytic mechanism through transient intermediate detection.