Synthesis and optimization of nanocomposite membranes based on SPEEK and perovskite nanoparticles for polymer electrolyte membrane fuel cells

Abstract

The addition of BaZr_0.9Y_0.1O_3−δ (BZY10) nanoparticles as a perovskite material with a proton conductor oxide structure to enhance the performance of sulfonated poly(ether ether ketone) (SPEEK) in proton exchange membrane fuel cells (PEMFCs) has been investigated in this work. The presence of hydroxyl ion functions in this material as a compatibilizer enhances the physical interactions between the polymer matrix and inorganic nanoparticles, leading to higher proton conductivity and improvement in thermal, mechanical and oxidative stability. Design-Expert software (DoE) and three-factor response surface modeling (RSM) were utilized for optimization of the BZY10 nanoparticle incorporation and degree of sulfonation (DS) of SPEEK regarding the experimental data obtained for proton conductivity, water uptake, and oxidative and mechanical stability, for different ranges of BZY10 nanoparticle combinations (0.5–2.5 wt%) in SPEEK with different DS amounts (65–73%). The optimized conditions to achieve the highest performance of PEMFCs were determined to be 1.8 wt% of nanoparticle incorporation in SPEEK with a DS of 69%. The nanocomposite membranes displayed the highest proton conductivity of 0.091 S cm⁻¹ at 80 °C, which is 31.87% higher than that of a pristine SPEEK membrane. The optimized membrane has been investigated in detail and reached a peak power density of 0.44 W cm⁻² at 80 °C. The novel SPEEK–BZY10 nanocomposite membranes with well-defined proton transport channels can be considered as potential alternative materials for PEMFCs.