Plasma techniques for the fabrication of polymer electrolyte membranes for fuel cells

Abstract

Polymer electrolyte membrane, as the indispensable component of a polymer electrolyte membrane fuel cell, serves a bi-function of conducting protons or hydroxide ions and separating fuels and oxidant, largely determining the performance of the corresponding polymer electrolyte membrane fuel cell. Therefore, the development of polymer electrolyte membranes that can efficiently conduct protons (for proton exchange membrane fuel cells) or hydroxide ions (for anion exchange membrane fuel cells) but block fuel permeation through membranes is a promising way to improve the electrochemical performance of polymer electrolyte membrane fuel cells. The plasma technique has shown great advantages in this area. It has been reported that the polymer electrolyte membranes modified or directly synthesized by the plasma technique exhibit superior properties, such as higher ion conductivity, low fuel permeability, high thermal and chemical stability, which provide them with great potentials as promising polymer electrolyte membranes for polymer electrolyte membrane fuel cell applications. However, the plasma polymerization is a very complicated process which involves the degradation of monomers and the formation of polymers. Therefore, the conditions used for the membrane modification and preparation must be well controlled to obtain membranes with desirable properties. This review paper is concerned with applications of the plasma technique in the preparation of polymer electrolyte membranes for uses in polymer electrolyte membrane fuel cells. The various plasma techniques that have been used for the modification and the preparation of polymer electrolyte membranes are reviewed and their associated advantages and disadvantages are discussed.