Polymer electrolyte membranes for fuel cell applications

Abstract

1.1. Introduction Fuel cells have been developed since 19th century but their first use was found in the exploration of space. After that its development has gone through several modifications and activities. However, from the past two decades their development gains significant and continuous efforts around the world to discover new materials and fuel cell systems. These efforts demands energy efficient systems, reduced emission of polluting gases such as CO2 and the need of high energy density system for portable applications such as mobile phones, laptops, iPod, digital camera and other portable electronic devices. Polymer electrolyte membrane (PEM) fuel cell systems are well-thought-out the more desirable portable electricity producing device for transport and portable uses and it is composed of highly efficient and pollution free setup.1, 2 But the main problem in modern fuel cell systems is to discover some other membranes than perfluorinated one, such as Nafion® (DuPont). Perfluorinated membranes show good proton conductivity and physical and chemical stability at and#8804; 80°C, but it deteriorates at and#8805;110°C1. Also, high gas permeability, high cost of production and fluorination processes are some of the serious drawbacks. Despite, Nafion® is being used in the present fuel cell systems, but, it has several demerits against the efficient PEM in fuel cell system. To develop efficient fuel cell membranes, various research groups are doing research in developing alternative membranes.3 Non-fluorinated moieties with ionic content4, acid containing polymers5, organic/inorganic blends6, solid acid with super-protonic phase transition7, and acid/base ionic liquids8 are some of the categories in which the present day researchers are concentrating. Moreover, processing of the material is also a very important factor in constructing membranes as a polyelectrolyte.