ABSTRACT
Large-scale utilization of conventional energy resources depletes fossil fuel reserves and pollutes the ecosystem. Therefore, there is an urgent requirement to find a significant energy source that alleviates both of these issues. In this context, fuel cells are potential candidates, generating electricity in an eco-friendly manner, with neither noise and air pollution, and producing only water and heat as by-products. Among the different categories of fuel cells (FCs), proton exchange membrane (PEMFC) and direct methanol fuel cell (DMFC) have advantages of compactness, high power density, easy start-up and maintenance that enhance their applicability in transportation, mobile and stationary applications. The membrane is the foremost component of FCs that acts as an electrolyte to promote circuit completion for electricity generation. Dupont's Nafion® is commercially used in FCs, however, its high cost, instability at high temperatures, high methanol crossover and catalyst poisoning limits its usage and restricts commercialization of FCs. Therefore, to accelerate breakthroughs in the development of alternative proton exchange membranes, this chapter combines discussions on both the fundamental and application aspects of PEMFC and DMFC membranes, with a focus on polyion complexes, owing to their inexpensive nature and sustainable properties. Synthesis and characterization of different polyion complex membranes have been presented through case studies that project desirable FC properties, such as ion exchange capacity, proton conductivity, water sorption, methanol uptake, in addition to mechanical and thermal stability. Robust but inexpensive polyion complex membranes could constitute the future solid polymer electrolyte in fuel cells.
