Hybrid Metal-Organic Framework-Derived Dual Active Site Catalysts Enabling Surface-Enriched Cathode and Modified Zinc Anode for Long-Life Zinc-Air Batteries.

The surface modification of zinc anodes and the development of effective cathode dual-functional oxygen electrocatalysts remain of paramount interest for enhancing the cycle life of rechargeable zinc-air batteries. The present work provides a sustainable synthesis of CoNi-based composites that can be used as cathode and anode side catalysts in Zn-air batteries. CoNi-metals with hybrid-metal organic frameworks (Hybrid-MOFs) and MOF-derived composites from curcumin-melamine (C-M) and benzene-1,3,5-tricarboxylic acid (BTC) were created for cathode and anode composites using reflux and hydrothermal techniques. In this instance, the cathode composite can be referred to as CoNi-N-C after annealing, whereas the anode composite can be referred to as CoNi-BTC without annealing. Thereafter, the formation of CoNi-N-C and CoNi-BTC composites was confirmed by microscopic, X-ray photoelectron, and X-ray diffraction techniques. As a result, structurally tailored CoNi-N-C and CoNi-BTC composites perform efficiently in electrochemical processes such as oxygen evolution/reduction reactions (OER/ORR) and energy conversion devices (Zn-air battery). Primarily, the CoNi-N-C catalyst exhibits the lowest overpotential (Ei = 10 = 1.48 V) and better half-wave potential (E1/2 = 0.781 V) in OER/ORR reactions; secondary CoNi-BTC composites coated on the Zn anode have the highest specific capacity (756.3 mA h gzn -1) and 1000-cycle charge-discharge stability in Zn-air batteries.