Development of Mn Doped Fe-N-C Electrocatalyst for Metal Air Batteries

Abstract

Metal air batteries (MABs) are an emerging technology due to their ability to store and deliver renewable energy effectively and an impressively high energy density. The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are fundamental reactions in MABs that are catalyzed by noble metal based electrocatalysts. For practical purposes, cheap alternative materials are required that offer good performance parameters like activity, selectivity, and stability. MetalNitrogen-Carbon (M-N-C) materials are a potent and widely researched materials as substitutes for ORR electrocatalyst and considered for their bifunctional properties. In this research project, a facile co-precipitation method is used an Fe-BNC electrocatalyst was prepared with 0%, 2% and 4% doping of manganese. The materials are characterized by using XRD for phase confirmation, SEM for studying the morphology and surface properties. FTIR and Raman spectroscopy was utilized for identification of functional groups. The electrochemical techniques like cyclic voltammetry, Linear Sweep Voltammetry and Electrochemical Impedance Spectroscopy were utilized to test the electrochemical performance of the material. The oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) are fundamental reactions in MABs that are catalyzed by noble metal based electrocatalysts. For practical purposes, cheap alternative materials are required that offer good performance parameters like activity, selectivity, and stability. MetalNitrogen-Carbon (M-N-C) materials are a potent and widely researched materials as substitutes for ORR electrocatalyst and considered for their bifunctional properties. It is observed that the addition of manganese enhances the activity and stability of the prepared catalysts. The best activity was observed for sample with 2% doping. While boron has size similar to carbon and manganese has size similar to iron, the electronic structure of both species can be tuned by incorporating Mn. The optimum Mn doping is linked to the Sabatier principle that binding energies must be within a specific range for highest activity.