PSSA/PVDF Polymer Electrolyte Membranes for CH₃OH Fuel Cells

Improved polymer electrolyte membranes for direct methanol fuel cells can be made by any of a variety of processes in which cross-linked polystyrene sulfonic acid (PSSA) is mobilized within electrochemically inert matrices of poly(vinylidene fluoride) (PVDF). Alternatively, other matrix materials can be substituted for, or blended or copolymerized with, PVDF. The principal advantage of these membranes over polymer electrolyte membranes made of other materials is that they are less permeable to methanol; this translates to less crossover of methanol in molecular form (denoted "methanol crossover" for short). Methanol crossover is undesired because it wastes fuel and degrades fuel-cell performance, as explained below.