Computational investigation of a protic ionic liquid doped poly-benzimidazole fuel cell electrolyte

Abstract

In this investigation, the structure and dynamics of N,N-diethyl-N-methylammonium triflate, ([dema][TfO]) Protic Ionic Liquid (IL) doped polybenzimidazole as a fuel cell electrolyte is explored, via molecular-dynamics simulations. The effect of IL wt% and temperature on ion-ion and ion-PBI interactions, diffusion coefficients of ions and ionic conductivities are calculated. The simulations predict anions of the IL preferably interact with the interactions site on the PBI, which leads to relatively smaller contribution to ionic conductivity. The ion-ion interactions increase with IL wt% with an opposite trend seen in ion-PBI interactions. The simulated ionic conductivity shows a significant increase at higher IL wt% and temperature and is in qualitative agreement with experimental ionic conductivity.