Tuning Proton Exchange Membrane Electrolytic Cell Performance by Conditioning Nafion N115-Based Membrane Electrode Assemblies

Conditioning of the membrane electrode assembly (MEA) is an important step to establish functionality and obtain a consistent performance of the proton exchange membrane electrolytic cell (PEMEC) when setting it into operation. On a laboratory scale in an academic context, conditioning encompasses primary pre-treatment of the MEA by chemical or thermal procedures under defined mechanical conditions and, secondarily, the break-in procedure, during which the PEMEC is subjected to initial electrical loads before actual operation. This study demonstrates the effect of MEA conditioning on the short-term performance of PEMEC. The impact of mechanical, chemical and thermal conditions during pre-treatment was investigated for Nafion N115-based MEAs while keeping the break-in procedure invariant for all pre-treatment conditions. The electrochemical characterisation was performed using polarisation curves and electrochemical impedance spectroscopy. The impact of ex situ–before assembly of the cell–versus in situ–after assembly of the cell–conditioning resulted in markedly different mechanical conditions. The experimental results showed an improvement in PEMEC performance by pre-treating the MEA after cell assembly. Compared to pre-treatment with deionised water (DI water) at 60°C, treatment with acidic solution improved the performance, evidenced by a 21 mV reduction in cell voltage at 2 A·cm⁻². When compared with DI water at 60°C, a pre-treatment at 90°C with DI water reduced cell voltage by 23 mV.