Manganese-cobalt mixed oxide film as a bifunctional catalyst for rechargeable zinc-air batteries

Rechargeable Zn-air batteries (ZABs) are receiving interest as promising energy storage devices owing to their high theoretical energy density. One of the major challenges in developing rechargeable ZABs is the slow kinetics of oxygen reduction and evolution (ORR/OER) on the air electrode during battery discharging and charging. Here, we report on a composite air electrode consisting of a Mn-Co mixed oxide electrocatalyst film on a carbon gas diffusion layer synthesized via anodic electrodeposition. The Mn-Co oxides have a fibrous structure and exhibit high catalytic activity towards both ORR and OER. ZAB test results show that the catalyst reduces the discharge-charge voltage gap and improves the round-trip efficiency in comparison with the baseline Pt-Ru/C catalyst. Furthermore, the catalyst remains stable for repeated cycles. (C) 2016 Elsevier Ltd. All rights reserved.