Fig. 2. Electrochemical characterization of MEAs based on different membranes 160°C, anode: H₂ (λ = 1.2), cathode: O₂ (λ = 2.0).

a AST (repeating chronopotentiometry between 0.6 A cm⁻² for 4 min and 1 A cm⁻² for 16 min, running OCV for 10 min every 6 hr), b polarization curves before AST, c polarization curves after AST, d EIS curves before AST (Nyquist plots, DC: 0.5 A cm⁻², frequency:10 kHz–0.1 Hz), e EIS curves after AST (Nyquist plots, DC: 0.5 A cm⁻², frequency:10 kHz–0.1 Hz).