Fuel cells are a promising technology as they convert chemical energy into electricity but remain expensive due to the use of noble metal catalysts. Alkaline fuel cells (AFCs) with anion exchange membranes (AEMs) offer a more affordable alternative by enabling the use of non-precious metal catalysts. [1] When fuelled with ethanol, they operate as direct ethanol fuel cells (DEFCs), benefiting from ethanol’s low toxicity and easier handling compared to hydrogen. However, current AEMs still do not meet commercial performance requirements. Biopolymers such as chitosan (CS) and bacterial nanocellulose (BnC) provide renewable, easily modifiable membrane materials, although their ionic conductivity and mechanical stability are limited. [2], [3] These limitations can be addressed through fillers, functionalisation, and crosslinking. Self-standing AEMs based on CS and BnC biopolymers, functionalised with N-doped reduced graphene oxide nanoribbons and quaternary ammonium, and crosslinked with naturally derived genipin, were investigated. The resulting membranes were assessed for properties relevant to DEFC applications, including ATR-FTIR, XRD, SEM imaging, ethanol permeability, alkali uptake, dimensional stability, ionic conductivity (up to 0.212 ± 0.019 mS/cm for CS-based AEMs), and single fuel cell performance in a DEFC set-up reaching (up to 17 mW/cm2 for CS-based AEMs), indicating their potential for use as AEMs in membrane electrode assemblies for DEFCs.
The authors would like to acknowledge the financial support from the Slovenian Research Agency (grant numbers N2-0087, Z2-60175, J2-50086, and P2-0118).
[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, vol. 5,no. 3,pp.604–637, 2021.
[2] S. Zdovc, M. Hren, and S. Gorgieva,“Bacterial nanocellulose-based composite membranes for fuel cells applications,”J.Power Sources,vol.665,p.239045, 2026.
[3] M. Hren, M. Roschger, V. Hacker, B. Genorio, D. Fakin, and S. Gorgieva,“High performance chitosan/nanocellulose-based composite membrane for alkaline direct ethanol fuel cells,”Int. J. Biol. Macromol.,vol. 253, 2023.
