XION Composite DYNEON Membranes are ultra-thin, highly conductive, and highly stable reinforced proton exchange membranes (PEM). The membrane is based on a perfluorosulfonic acid (PFSA) ionomer developed by 3M. The low equivalent weight and modification to the PFSA structure by 3M leads to the highest conductance material compared to traditional ionomers like NAFION. A reinforcement layer is integrated into the structure of the membrane to provide enhanced mechanical properties. The enhanced mechanical properties allow Ultra-thin, Ultra-Strong, and Ultra-High-Performance free-standing membranes, i.e. providing higher ionic conductivity without sacrificing strength. Applications for XION Composite DYNEON Membranes include fuel cells, electrolyzers, and sensors. XION Composite DYNEON Membranes come in two variations based on the equivalent weight (EW) of the ionomer. 725EW has higher ionic conductivity, but 800EW has greater stability.