Multiscale collaborative optimization guided synthesis of ZIF&MOG-derived bifunctional electrocatalysts fabricated via in-situ self-assembly in carbon nanofibers for durable zinc-air batteries

Abstract

As key materials in high-efficiency clean energy technologies, zeolitic imidazolate framework (ZIF) and metal-organic gel (MOG) materials have shown great potential. However, they suffer from issues such as insufficient electrical conductivity, stability, and active sites. To enhance the comprehensive performance of electrocatalytic materials, In this study, electrospinning technology was adopted to in-situ embed the ZIF-MOG precursor during the formation process of nanofibers. A graphene conductive fiber network was constructed through the high temperature carbon ring closure of organic fibers, resulting in the fabrication of the efficient catalyst of ZIF-MOG derived carbon nanofibers (ZM-CNF) with dual functions of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Raman spectroscopy and BET tests indicate that the ZM-CNF material has a high specific surface area, an appropriate degree of graphitization, and a mesoporous distribution. Electrochemical analysis indicated that the ORR half-wave potential for this catalyst is as high as 0.80 V, and the overpotential for OER is 396 mV at a current density of 10 mA cm⁻². By means of a balanced design of defect engineering and conductive networks, ZM-CNF achieved a synergistic optimization of catalytic performance and charge transfer efficiency. In the application test of zinc-air batteries, the battery assembled with ZM-CNF achieved a maximum power density of 115.7 mW cm⁻² and an open-circuit voltage of 1.442 V, which is comparable to the performance of the battery assembled with the commercial Pt-RuO₂ catalyst. During the 180 h charge-discharge cycle test, the charge-discharge efficiency of the ZM-CNF battery did not exhibit significant attenuation, demonstrating excellent electrocatalytic performance and cyclic stability. This study broadens the perspective for the structural regulation design of high-performance composite catalysts for energy storage and conversion applications.