Fabrication of chitosan based composite membranes with functionalized nanofibrillar cellulose fillers for alkaline fuel cell applications M. Hren 1* , M. Roschger 2 , V. Hacker 2 , B. Genorio 3 , D. Makuc 4 , J. Plavec 4 , S. Gorgieva 1 1 Faculty of Mechanica Engineering, University of Maribor, Maribor, Slovenia, 2 Institute of Chemical Engineering and Environmental Technology, Graz University of Technology, Graz, Austria, 3 Faculty of Chemistry and Chemical Technology, University of Ljubljana, Ljubljana, Slovenia, 4 Slovenian NMR Centre, National Institute of Chemistry, Hajdrihova 19, Fuel cells are promising devices for direct conversion of chemical energy into electrical energy that can be used in many applications. However, commercialization of the currently most advanced hydrogen fuel cells is hindered by the high cost of some components, such as platinum-based catalysts. As a more economical alternative, alkaline anion exchange membrane fuel cells(AAEMFCs) are gaining increasing attention as promising electrochemical devices for power generation and as a serious counterpart to the better studied proton exchange membrane fuel cells. [1] AAEMFCs contain an anion exchange membrane(AEM) as a solid polyelectrolyte between the electrodes and can employ non-precious metal catalysts on the electrodes, which drastically reduces the cost per kilowatt of power for such fuel cell devices. Currently commercially available AEMs do not exhibit satisfactory characteristics that would enable the commercial breakthrough of AAEMFCs, indicating the need to develop new high-efficiency, easy-to-manufacture, environmentally friendly, and economically viable AEMs. Synthesis of synthetic polymeric AEMs is typically complex, time-consuming, and environmentally unfriendly. Alternatively, naturally derived materials can be used, and chitosan(CS), cellulose nanofibrils(CNF), and nanocrystalline cellulose have been proposed as promising so far [2] , [3] Despite all this, biopolymer-based AEMs are still not advantageous compared to synthetic AEMs, especially in terms of ionic conductivity and mechanical properties, which can be improved by introducing appropriate fillers.This work discusses the perfermance of a series of biopolymer-based AEMs fabricated by a simple and cost-effective solution casting technique in accordance with green chemistry principles. Quaternized CNFs were prepared and embedded in the CS matrix to produce CS-based AEMs for use in AAEMFCs. Unlike the neat CNF filler, the quaternized CNF fillers contributed a permanent positive charge to the CS-based AEMs, which is highly desirable. The fillers were analysed by ATR-FTIR, 13 C NMR and 29 Si spectroscopy, FE-SEM,TGA,DSC analysis and zeta potential measurements. Design of experiments was used to determine optimal combinations of influencing factors and their relationship to selected responses (i.e.,membrane properties). The obtained CS-based composite membranes containing CNF and quaternizedCNF fillers were investigated for their structural properties, swelling ratio and alkali uptake, ethanol permeability, ionic conductivity, ion exchange properties and characterised in an AAEMFC and compared to the reference Fumatech membrane. The obtained data indicate the applicability of the newly prepared chitosan-based composite membranes as AEMs in AAEMFC technologies. Acknowledgments: Financial support was received in the frame of the Slovenian Research Agency Young Researcher Programme and Textile Chemistry programme(P2-0118/0795) and project“GO DEFC”(Grant number N2-0087). References 1. M.Hren; M.Božič; D.Fakin; K.S. Kleinschek;and S. Gorgieva. Alkaline membrane fuel cells:Anion exchange membranes and fuels. Sustain.Energy Fuels 2021 , 5 ,604–637. 2. S.Gorgieva et al. Efficient chitosan/nitrogen-doped reduced graphene oxide composite membranes for direct alkaline ethanol fuel cells. Int.J.Mol.Sci. 2021 , 22 ,1–25. 3. M.Hren et al. Chitosan-Mg(OH)2 based composite membrane containing nitrogen doped GO for direct ethanol fuel cell. Cellulose 2021 , 28 ,1599–1616. Ljubljana, Slovenia * masa.hren@um.si
P172E
Made with FlippingBook Learn more on our blog