Effect of Temperature and Water Content on Thermal Conductivity in Ordered and Amorphous Proton Exchange Membranes: A Molecular Dynamics Study

Proton exchange membrane (PEM) is the key component of proton exchange membrane fuel cell. The thermal conductivity of the PEM determines the efficiency of heat dissipation through various cooling methods, directly impacting the fuel cell’s performance. Imparting order to Nafion molecules is a potentially effective method to significantly improve the thermal conductivity of PEM. However, the intrinsic mechanism of this effect as well as the regulatory mechanism is still unclear. In order to investigate the regulatory mechanism of temperature and water content on the thermal transport mechanism of PEM and to compare the thermal transport properties of ordered and amorphous membranes, this study used reverse non-equilibrium molecular dynamics simulations (RNEMD) to investigate the thermal conductivity of ordered and amorphous membranes at 300 K and 350 K under different water content conditions. The simulation results show that it is effective to improve the thermal conductivity of PEM by imparting order to Nafion molecules, and the thermal conductivity of the ordered membrane is approximately twice that of the amorphous membrane. Furthermore, it was also found that increasing temperature and hydration level can enhance the thermal conductivity of both ordered and amorphous membranes.