Membranas basadas en líquidos iónicos para su aplicación como electrolitos en pilas de combustible

Abstract

Fuel cells are considered a key technology for providing sustainable energy due to their high energetic efficiency and low environmental impact. Proton Exhange Fuel Cells (PEMFC) usually use as electrolyte a solid polymer called Nafion, which is mechanically, thermally and chemically stable and shows very high values of proton conductivity. However, to ensure proton exchange the membrane needs to be hydrated. This situation may involve a limitation creating the necessity to develop alternative electrolytes to Nafion. One of the newest ways to do this is to study the use of ionic liquids as electrolytes in fuel cells because of their high ionic conductivity even under anhydrous conditions. The formation of a solid electrolyte by polymerization of ionic liquids represents an attractive alternative to traditional Nafion membranes due to high ionic conductivities expected even under anhydrous conditions. In this work a polymerization of ionic liquid trifluoromethanesulfonate 3-vinyl-1-(4-sulfobutyl) imidazolium has been done by ultraviolet light for their use as electrolyte in PEMFC under various operating conditions. The influence of three variables was analyzed: cell temperature, gas humidification and contact between the membrane and GDES (Gas Diffusion Electrodes) through the process of pressing. Also, employing the technique of impedance spectroscopy (EIS) was determined the resistance exerted by the electrolyte at the operating conditions studied, providing a better understanding of the mechanisms involved in energy production.