MOF-derived CoFe alloy nanoparticles encapsulated within N,O Co-doped multilayer graphitized shells as an efficient bifunctional catalyst for zinc--air batteries

Metal-organic frameworks (MOFs) and their derivatives are promising electrocatalysts for zinc-air batteries due to their advantages of reconfigurable metal nodes and abundant coordinatively unsaturated active sites. However, current MOF-derived composites are mostly microporous and have low graphitization, which are deemed unfavourable for ion and electron transport. Herein, we report CoFe alloy nanoparticles encapsulated in N,O co-doped multilayer graphitized shells as effective bifunctional catalysts as well as the simple and practical preparation of cobalt/iron MOFs and their subsequent carbonization. The resulting heteroatom-doped carbon highly graphitized bimetallic catalysts were examined by electrochemical tests and deliver a minimum Delta E (Delta E = E-j10 - E-1/2) of 0.678 V and exhibits high durability after long-term testing. The homemade zinc-air battery has a high power density (>200 mW cm(-2)) with a high specific capacity (829.5 mA h g(-1)). In addition, the zinc-air battery exhibits high stability during battery cycling processes. Therefore, this work provides a promising pathway for advanced metal-air cathode materials.

Automated summary

In this study, CoFe alloy nanoparticles encapsulated in N,O co-doped multilayer graphitized shells were used as effective bifunctional catalysts for zinc-air batteries. The resulting heteroatom-doped carbon highly graphitized bimetallic catalysts showed high durability and the homemade zinc-air battery exhibited high power density and high specific capacity with excellent stability during battery cycling processes.