Research of the Kinetics of the Hydration Process of Proton Exchange Membranes

Polymer proton-exchange membranes are an important component of various electrochemical devices. Such membranes are used in electrolyzers, sensors, water purification systems and in the synthesis of complex chemical compounds. However, proton-exchange membranes are most widely used as a separating electrolyte in proton exchange membrane fuel cell (PEMFC), which directly convert the chemical energy of the hydrogen-oxygen system into electrical energy, bypassing combustion processes. To create effective PEMFC generators, it is necessary that the proton-exchange membrane have a number of functional properties, including high kinetics of hydration (water sorption) at different ambient humidity. A lot of work has been devoted to the study of kinetic processes of water sorption by proton-exchange membranes, but these studies were mainly carried out on perfluorinated sulfopolymers of the Nafion type by measuring the dependence of the mass gain of the sample during membrane hydration. No studies have been conducted on the evolution of proton conduction, which determines the functional features of PEMFC, for this type of process. In this work, using the method of impedance spectroscopy, the change in proton conductivity during membrane hydration was studied at various values of humidity in the surrounding atmosphere. At the same time, such measurements were carried out both on the commercial Nafion 211 membrane and on the fluorine-free polynaphthoylenimide membrane. This membrane is a completely domestic development and was manufactured at INEOS RAS in 2022.