Development of ZIF-67 Derived Electrocatalyst for Oxygen Electrode in Metal Air Batteries

Abstract

Scientists and researchers have been pushed to investigate alternate methods of energy conversion and storage by the widespread usage of fossil fuels and the attendant environmental issues. In this endeavor, metal-air batteries, fuel cells, and water splitting have emerged as potentially promising routes to pursue. The high energy density and environmental sustainability of metal-air batteries have led to their emergence as a potentially useful technology for the storage of electrical energy. Nevertheless, the slow oxygen evolution reaction (OER) at the anode continues to be a substantial obstacle, which impedes both the overall performance of metal-air batteries and their applications in real world. ZIF-67 and its composites with reduced graphene oxide (RGO) and manganese (Mn) are the materials that are being investigated for their potential use in the development of an effective electrocatalyst for oxygen electrode in MABs as part of this research. Using the solvothermal method, we synthesized ZIF-67, 1-5wt% rGO/ZIF-67, and 1- 5wt% rGO/Mn ZIF-67. XRD, SEM, Raman, and FTIR characterization techniques were used. We performed cyclic voltammetry, chronopotentiometry, EIS, and LSV tests for electrochemical study. The overpotential values for ZIF-67 were calculated as 154mV at 10 mAcm-2 . By the addition of rGO, overpotential values were reduced. The optimum addition of rGO was 3wt% as it gave an overpotential value of 136mV 10 mAcm-2 . The addition of 5wt% rGO caused the blockage of active sites. The addition of Mn significantly improved the activity of ZIF-67. 3wt% rGO/Mn ZIF-67 outperformed all the compositions of catalysts being performed in this study, with an overpotential value of 113 mV at 10 mAcm-2 . According to the findings of the study, the electrocatalyst that was developed from ZIF67 has superior levels of catalytic activity and stability in comparison to traditional catalysts used in metal-air batteries, particularly for the reaction that involves oxygen evolution. The addition of RGO and Mn to structure of ZIF-67 provides additional active sites for the OER and makes electron transfer more efficient, both of which contribute to iv an overall improvement in performance. These findings give important new insights into design and synthesis of effective electrocatalysts for MABs, thereby expanding field of environmentally friendly technologies for the storage of energy.