Impact of Cell Drying on Fuel Cell Performance Over Lifetime

Abstract

Drying of the membrane electrode assembly (MEA) during fuel cell (FC) operation is a well-known water management issue that limits long-term durability. Although drying effects have been widely studied using pristine MEAs, this work investigates their impact on industrial-scale MEAs at two distinct lifetime stages: beginning of life and after 8000 h of prior stack operation (middle of life, MoL). Drying was induced through an accelerated stress test (AST), which was based on real-life conditions in automotive and heavy-duty applications. The effects on the membrane were fully reversible in both MEAs; however, the harsh dry conditions caused an irreversible increase in mass transport resistance, as well as irreversible voltage losses and electrochemical surface area (ECSA) reduction, particularly in the MoL MEA. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) analysis revealed ionomer redistribution and agglomeration after the AST, with the MoL MEA showing stronger degradation due to previous long-term operation combined with the AST exposure. These findings show that the lifetime stage of the FC strongly influences the vulnerability to dry operation and provide novel insights into long-term performance under realistic conditions.