Hydrogen proton exchange Specialized Membrane

Still higher total conductivities are achievable in a special class of hydrogen-ion (proton)-conducting polymers. These polymers are particularly useful for fuel-cell and chlor-alkaU processing applications in which the efficient transfer of protons is critical. These polymers are of produced in membrane form and are therefore referred to as proton-exchange membranes (PEM). 

Fuel cells are typically classified according to the types of the electrolytes they use. There are alkaline fuel cells (operating temperature -60-200 °C), phosphoric acid fuel cells ( 120-210 °C), molten carbonate fuel cells ( 650 °C), solid oxide fuel cells (-600-1000 °C), and proton-exchange membrane (PEM) fuel cells (RT-90 °C). A direct methanol fuel cell (DMFC) can be considered as a special type of the PEM fuel cell that uses methanol (in either vapor or liquid form) rather than hydrogen as the fuel. This review article focuses exclusively on PEM fuel cells. 

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