Nafion™ HP membranes are ultra-thin cation exchange membranes that are manufactured by the Chemours Company. These membranes are reinforced and designed for lower relative humidity environments and high operating temperature. The reinforcement improves the membrane’s handling and physical properties. When the reinforcement is combined with the chemically stabilized polymer, the Nafion™ HP membrane exhibits both substantially lower fluoride ion release and longer operating durability under challenging fuel cell conditions. Nafion™ HP is 20.3 micrometers (0.8 mil) thick. The membrane is positioned between a backing film and a coversheet.