Numerical modeling of Nafion membranes to predict their performance under different operating conditions

The proton conductivity of Nafion (DuPont) membranes plays a critical role in the performance of Proton Exchange Membrane (PEM) electrochemical cells, as it governs the membrane's ability to transport hydrogen protons (H+) between the anode and cathode. While numerous studies have been conducted on the conductivity of Nafion membranes, to date, no dedicated experimental campaign has focused on the characterisation of through-plane conductivity of several Nafion membranes, under different operating conditions, to develop a predictive model of their performance. This research work aims to address this gap by investigating the through-plane conductivity of non activated NR212, N115 and N117 membranes. The study was carried out using a Membrane Testing System (MTS), where relative humidity levels (20% to 95%) and temperature conditions (30° C to 80° C) were systematically varied. A new numerical empirical model was developed in the Python programming environment to predict the membranes' performance. In particular, the model was first calibrated using experimental data of NR212 and N117, and then validated using those of N115. The model shows a good reliability for all the operating conditions tested, with a minimum and maximum value of the Root Mean Square Error (RMSE) of 1.1 mS/cm and 4.7 mS/cm at 50° C and 80° C, respectively. Furthermore, to the authors' knowledge, no through-plane conductivity data of non activated N115 and N117 have been published yet, revealing that this is the first research work to fill this scientific gap.