Confined PFSA/MOF composite membranes in fuel cells for promoted water management and performance

A novel kind of confined PFSA/MOF composite membranes was developed to promote the water management within the membrane during the PEMFC operation. Two typical water-stable MOFs (i.e., ZIF-8 and MIL-101) were grown on the surface of polydopamine (PDA) or polydopamine/polyethyleneimine (PDA/PEI) modified perforated stainless steel meshes, and subnanoliter of PFSA was confined within the pores of as-prepared substrate. The composite membranes can be operated at high temperatures without external humidification. The PEMFC with confined PFSA/ZIF-8 composite membrane and confined PFSA/MIL-101 composite membrane exhibit three times higher power density than the one with commercial Nafion 117 membrane at 60 degrees C. The improved performance benefited from the good water retention capacity and thermal stability of MOF facilitating proton transfer and water management under high temperature and dry conditions.