The goal of this Research is to make a proton exchange membrane with an improved functional group for use as PEMs in fuel cells. The emphasis of the work is to produce a PEM which operates at higher temperatures(>120˚C) and that has better proton conducting properties then the current sulfonic acid polymer such as Nafion®. The polymers being developed are known as perfluorosufonimide ionomers or PFSI. Numerous polymers are made which incorporate bis[(perfluoroalkyl)sufonyl]imide function onto a Teflon backbone. Polymers with higher equivalent weight have lower conductivity but better mechanical properties, whereas polymers with lower equivalent weight have higher conductivity but poor mechanical properties. We have explored blending of polymers, one with lower and the other with higher equivalent weight to give a polymer with higher conductivity and better mechanical properties. The resultant polymer obtained show better conductivity than their components especially at higher temperature 120°C. Composite membranes of PFSI ionomers with ZrO2 , and with heteropolyacid have been prepared, which show higher conductivity and good thermal stability.