Research and Progress in Mitigating Carbon Oxidation in Air Electrodes

Abstract

Oxygen electrocatalysis plays a pivotal role in fuel cells and metal-air batteries, which hold immense potential for energy conversion and storage systems due to their superior theoretical energy density, cost-effectiveness, and safety profile. However, carbon-based materials in air electrode face challenges stemming from the harsh oxidative environment of oxygen catalysis, leading to thermodynamic instability. This underscores the urgent necessity for the development of effective carbon anti-oxidation strategies. This comprehensive review initially explores the complex mechanisms underlying the oxygen reduction/oxygen evolution reactions (ORR/OER) and the prevalent issue of carbon corrosion in carbon-based materials. It then delves into diverse strategies aimed at mitigating catalyst corrosion through doped carbons, encompassing techniques such as graphitization, active site management, surface modification using functional groups, and corrosion resistance coating. Moreover, the review discusses methods to counteract carbon oxidation in catalyst supports, including the utilization of novel carbons, highly active catalysts to minimize oxidation, and the exploration of non-carbon alternatives. Furthermore, the review also sheds light on protecting current collectors and conductive additives within the air electrode from corrosion. Ultimately, it outlines emerging challenges and opportunities for addressing carbon oxidation in air electrode, paving the way for enhanced performance and longevity in fuel cells and metal-air batteries.