Conductive metal-organic frameworks for zinc-air battery application: design principles, recent trends and prospects

Electrochemical energy conversion and storage systems have an indispensable place in the modern world to fulfill the increasing energy demands. Among the different storage devices, rechargeable zinc-air batteries (ZABs) have become one of the most promising energy technologies owing to the abundance and inexpensiveness of Zn, simple operation, environmental friendliness, and reasonable energy density. However, the sluggishness of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) occurring in ZABs is a serious obstacle in their progress and commercialization. This creates a need for the development of efficient bifunctional electrocatalysts for ORR and OER. Conductive metal-organic frameworks (cMOFs) imbibing the general properties of MOFs, like high surface area, tunable porosity, redox-active centers, and additional intrinsic conductivity, can be a very lucrative option for developing bifunctional ORR and OER electrocatalysts for ZAB applications. In this review, we discuss the conductivity and design strategies of conductive MOFs, the basic configuration of ZABs, and the use of cMOFs for ZAB applications. The future directions for the improvement of cMOFs for ZABs have been provided, which hopefully will incite interest among researchers for further exploring cMOFs for ZABs. Electrochemical energy conversion and storage systems have an indispensable place in the modern world to fulfill the increasing energy demands.