| New proton exchange membranes based on polymerized ionic liquids for fuel cells Lucia Gomez Coma1; Victor-manuel Ortiz Martínez1; Alfredo Ortiz1; Inmaculada Ortiz1; 1UNIVERSITY OF CANTABRIA, Santander, Spain; PAPER: 5/AdvancedMaterials/Regular (Oral) SCHEDULED: 16:20/Tue. 29 Nov. 2022/Saitong ABSTRACT: The development of new proton exchange membranes (PEMs) has gained growing attention in the last few years for their use in electrochemical devices [1]. Fuel cell, FC, technology is among the most relevant applications of PEMs. FCs directly convert chemical energy into electricity. A wide range of materials has been tested as membranes in fuel cells. Perfluorinated polymeric sulfonic acids (commonly known as Nafion<sup>®</sup>), however, are considered the standard PEM membrane type due to their advantageous properties, which include high proton conductivity, good mechanical strength and long lifetime. These advantages are counterbalanced by the high cost and the operational limitations under non-humidified and high-temperature conditions. On their part, polymeric ionic liquids (PILs) are attracting growing research interest as fuel cell membrane electrolytes because of their numerous advantages since they combine the unique properties of ionic liquids (ILs) and the intrinsic properties of polymers [2]. Several strategies to promote PIL membranes have been reported to date, based on (i) the incorporation of ILs into a polymer network by mixing both phases, typically by casting techniques, (ii) formation of solid membranes through conventional polymerization of IL monomers and (iii) a new attractive alternative consisting of IL photopolymerization, since this technique provides short synthesis times at room working temperatures and easy control [1]. This works focuses on the development of new PEMs through the photopolymerization of protic ILs such as 1-(4-sulphobutyl)-3-vinylimidazolium trifluoromethanesulphonate, ([HSO<sub>3</sub>-BVIm][TfO]). Several strategies have been followed to assess the performance of IL-based membranes: (i) photopolymerization of the IL in the absence of other monomers; (ii) photocopolymerization of the IL with methyl methacrylate (MMA) and iii) photocopolymerization of the IL with perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride in its hydrolyzed form (hPFSVE). The results show higher values of conductivity for the copolymerized membranes, within the range 10<sup>-3</sup> - 10<sup>-2</sup> S.cm<sup>-1</sup>, both in dry and wet conditions and even at room temperature. Thus, the new PEMs offer promising prospects for their application as PEMs in fuel cell devices. References: [1] Ortiz-Martínez V.M., Ortiz A., Fernández-Stefanuto V., Tojo E., Colpaert M., Améduri B., Ortiz I. Fuel cell electrolyte membranes based on copolymers of protic ionic liquid [HSO<sub>3</sub>-BVIm][TfO] with MMA and hPFSVE, Polymer, 179 (219) 121583. [2] M. Díaz, A. Ortiz, I. Ortiz. Progress in the use of ionic liquids as electrolyte membranes in fuel cells, Journal of Membrane Science, 469 (2014) 379–396. |
