NON-EQUILIBRIUM POROELECTROELASTIC THEORY OF POLYMER ELECTROLYTE WITHIN THE CONDITIONS OF WATER ELECTROLYSIS

Abstract

The paper considers a non-equilibrium poroelectroelastic theory of a polymer electrolyte under the conditions of water electrolysis with the purpose of further use for a theoretical description of mass transfer processes in l ayers of a membrane-electrode assembly. Moreover, this paper carries out the review and analysis of the models of electro- chemical and mass-exchange processes in the electrolyzers, and analyzes the problems of their physicochemical description. We make a conclusion about the need to use models of water sorption and scaling of polymer electrolyte and analyze the models of water sorption and swelling of the polymer electrolyte. It is concluded that the existing poroelectroelastic theory is the most suitable for its modification for use in non-equilibrium conditions during elec- trolysis. The basic equation of the balance of pressures of the classical equilibrium poroelectroelastic theory for polymer electrolyte is considered. A modification of the poroelectroelastic theory has been carried out in order to its use in non-equilibrium conditions of water electrolysis for the purpose of further modeling of mass transfer processes. Based on experimental data available in open sources, the paper makes an analysis of the properties and features of elastic forces in the polymer electrolyte, and then refines the dependencies of the elastic forces in the polymer electro- lyte from the swelling and temperature. Taking into account the existing experimental data on the permeability of gases in a polymer electrolyte and the feature of swelling of the polymer electrolyte in a contact with liquid water, parameters of the non-equilibrium poroelectroelastic theory have been obtained for the water electrolysis conditions.