Engineering Self‐Supported Hydrophobic–Aerophilic Air Cathode with CoS/Fe3S4 Nanoparticles Embedded in S, N Co‐Doped Carbon Plate Arrays for Long‐Life Rechargeable Zn–Air Batteries

Abstract

AbstractThe highly sluggish kinetics of oxygen reduction/evolution reactions (ORR/OER) at air cathodes lead to problems such as low power density and unsatisfactory cycling life with rechargeable Zn–air batteries (RZABs). To engineer the reaction kinetics at the air cathodes, a hydrophobic–aerophilic strategy is developed to fabricate a self‐supported air cathode based on CoS/Fe3S4 nanoparticles encapsulated in S, N co‐doped carbon plate arrays (CoS/Fe3S4@SNCP). It is experimentally shown that the in situ growth of bimetallic sulfides nanoparticles on the carbon plate arrays improves the intrinsic electrocatalytic activity and electron conduction of the air cathode. Meanwhile, the ab initio molecular dynamics simulations reveal that the hydrophobic–aerophilic surface can repel water molecules to create abundant solid–liquid–gas three‐phase reaction interfaces as well as to expose Fe‐sites, which consequently promote the diffusion of reactive molecules/ions across the interface and the oxygen adsorption. As a result, the CoS/Fe3S4@SNCP electrode exhibits excellent OER and ORR activities with a smaller potential gap of 0.65 V. For the engineered hydrophobicity of the catalyst, the RZAB demonstrates a high power density of 272 mW cm−2, a narrow discharge/charge gap of 0.75 V at 10 mA cm−2, and long‐term cycling stability over 1400 h, outperforming its hydrophilic CoS@SNCP counterparts.