Hydrophobization Engineering of the Air-Cathode Catalyst for Improved Oxygen Diffusion towards Efficient Zinc-Air Batteries.

Poor oxygen diffusion at multiphase interfaces in an air cathode suppresses the energy densities of zinc-air batteries (ZABs). Developing effective strategies to tackle the issue is of great significance for overcoming the performance bottleneck. Herein, inspired by the bionics of diving flies, a polytetrafluoroethylene layer was coated on the surfaces of Co 3 O 4 nanosheets (NSs) grown on carbon cloth (CC) to create a hydrophobic surface to enable the formation of more three-phase reaction interfaces and promoted oxygen diffusion, rendering the hydrophobic-Co 3 O 4 NSs/CC electrode a higher limiting current density (214 mA cm -2 at 0.3 V) than that (10 mA cm -2 ) of untreated-Co 3 O 4 NSs/CC electrode. Consequently, the assembled ZAB employing hydrophobic-Co 3 O 4 NSs/CC cathode acquired a higher power density (171 mW cm -2 ) than that (102 mW cm -2 ) utilizing untreated-Co 3 O 4 NSs/CC cathode, proving the enhanced interfacial reaction kinetics on air cathode benefiting from the hydrophobization engineering.