Engineering Self-Supported Hydrophobic–Aerophilic Air Cathode with CoS/Fe_3S_4 Nanoparticles Embedded in S, N Co-Doped Carbon Plate Arrays for Long-Life Rechargeable Zn–Air Batteries

摘要

The highly sluggish kinetics of oxygen reduction/evolution reactions (ORR/OER) at air cathodes lead to problems such as low power density andunsatisfactory cycling life with rechargeable Zn–air batteries (RZABs). Toengineer the reaction kinetics at the air cathodes, a hydrophobic–aerophilicstrategy is developed to fabricate a self-supported air cathode based onCoS/Fe_3S_4 nanoparticles encapsulated in S, N co-doped carbon plate arrays(CoS/Fe_3S_4@SNCP). It is experimentally shown that the in situ growth ofbimetallic sulfides nanoparticles on the carbon plate arrays improves theintrinsic electrocatalytic activity and electron conduction of the air cathode.Meanwhile, the ab initio molecular dynamics simulations reveal that thehydrophobic–aerophilic surface can repel water molecules to create abundantsolid–liquid–gas three-phase reaction interfaces as well as to expose Fe-sites,which consequently promote the diffusion of reactive molecules/ions acrossthe interface and the oxygen adsorption. As a result, the CoS/Fe3S4@SNCPelectrode exhibits excellent OER and ORR activities with a smaller potentialgap of 0.65 V. For the engineered hydrophobicity of the catalyst, the RZABdemonstrates 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 over1400 h, outperforming its hydrophilic CoS@SNCP counterparts.