Study on Mitigating Membrane Degradation in Degraded Membrane Electrode Assembly of Polymer Electrolyte Membrane Fuel Cell through Temperature and Humidity Control

Abstract

Polymer electrolyte membrane fuel cells (PEMFCs) have faced challenges in achieving their lifespan goals due to the degradation of the membrane electrode assembly (MEA) during long-term operation. To enhance the durability of PEMFCs, it is necessary to research materials that can improve the durability of the membrane and electrodes, as well as to study operating conditions that can reduce degradation. This paper investigated methods to mitigate the membrane degradation of electrochemically degraded MEAs by controlling humidity and temperature among the operating conditions. MEA was degraded electrochemically by conducting open circuit voltage (OCV) holding, and then the degradation rate according to temperature and humidity changes was observed through fluoride emission rate (FER) change. In a degraded MEA, it is shown that increasing cell humidity accelerates membrane degradation. According to linear sweep voltammetry (LSV) results, this was confirmed to be due to the increase in hydrogen permeability caused by the higher humidity. The decrease in temperature lowered the rate of membrane degradation, which is attributed to a decrease in the rate of radical attack and generation resulting from the temperature decrease. Therefore, it was confirmed that to mitigate membrane degradation in electrochemically degraded MEAs, it is effective to reduce temperature and humidity, thereby decreasing the rate of radical formation.