Answer
Nafion
Nafion is a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Walther Grot of DuPont. It is the first of a class of synthetic polymers with ionic properties which are called ionomers. Nafion's unique ionic properties are a result of incorporating perfluorovinyl ether groups terminated with sulfonate groups onto a tetrafluoroethylene (Teflon) backbone.Nafion has received a considerable amount of attention as a proton conductor for proton exchange membrane (PEM) fuel cells because of its excellent thermal and mechanical stability.
Role of Nafion
Nafion's properties make it suitable for a broad range of applications. Nafion has found use in fuel cells, electrochemical devices, chlor-alkali production, metal-ion recovery, water electrolysis, plating, surface treatment of metals, batteries, sensors, Donnan dialysis cells, drug release, gas drying or humidifaction, and superacid catalysis for the production of fine chemicals. Nafion is also often cited for theoretical potential (i.e., thus far untested) in a number of fields. With consideration of Nafion's wide functionality, only the most significant will be discussed below.
Role of Phosphoric acid in fuel cells
Phosphoric acid is used as an electrolyte in phosphoric acid fuel cells. Pure liquid phosphoric acid (H3PO4) saturated in a silicon carbide matrix (SiC) is used as electrolyte in different fuel cells. Operating range is about 150 to 210 °C. The electrodes are made of carbon paper coated with a finely dispersed platinum catalyst.
Use of H2SO4 and HCl
H2SO4 is normally used as electrolyte as Phosphoric acid. There is no evidences of use of HCl as electrolyte because HCl will produce Chlorine gas which is very reactive so HCl is avoided to use as electrolyte in fuel cells.
