Design and Development of Copper Trimesic Acid Anchored sPEEK/Polyimide Composite Membranes for Fuel Cell Applications

Electrolyte membranes play a critical role as their properties directly influences the performance of fuel cell. A copper-based metal organic framework (MOF) anchored polymeric blend membrane was developed for fuel cell application. Cu-MOF serves as an excellent filler material due to its small size, high degree of crystallinity and surface area. Through XRD analysis well defined crystallite sites was evidenced and the average crystallite size measured similar to 0.3 angstrom. The acidic functional group in MOF interacts with sulfonic acid (-SO3H) group in sulfonated polyetheretherketone (sPEEK) matrix which further improves proton conduction via. hydrogen bonding interaction. With the as-prepared sPEEK as the matrix; polyimide (PI) was blended to improve its processibility and thermal stability. Cu-MOF loaded composite membranes (X wt.% Cu-MOF-sPEEK/PI) were prepared and characterized. To assess the suitability of the developed membranes for proton exchange membrane fuel cell (PEMFC) applications, ion exchange capacity (IEC), water uptake and proton conductivity was measured. 3 wt.% Cu-MOF-2-sPEEK/PI membrane displayed an IEC value of 2.35 meq g(-1) with a water uptake of 38.18 % and proton conductivity of 0.0711 S cm(-1). Overall, the experimental results of the prepared membranes revealed that they act as an efficient proton exchange membrane (PEM) for PEMFCs.