Proton Conductivity of Composite Polyelectrolyte Membranes with Metal-Organic Frameworks for Fuel Cell Applications

The study of proton conductivity processes has gained intensive attention in the past decades due to their potential applications in chemical sensors, electrochemical devices, and energy generation. The scientific community has focused its efforts on the development of high-performing polymeric membranes as proton exchange membranes (PEMs) for fuel cell (FC) applications. In particular, high conductivity at different humidity and temperature and enhanced chemical and mechanical stability under operative conditions are considered the main goals to be reached. The design of mixed-matrix membranes (MMMs) based on conductive polymers and inorganic fillers is an approach commonly used for achieving materials with improved conductive and mechanical properties. In the last five years, the use of metal-organic frameworks (MOFs) as fillers for conductive MMMs has rapidly grown for their intrinsic stability and structural versatility. The recent progress around the proton conductivity of MOF based composite membranes on PEMs for FC applications is critically reviewed.