Vilela, CarlaMorais, JoãoSilva, Ana CristinaMuñoz Gil, DanielFigueiredo, FilipeSilvestre, ArmandoFreire, Carmen2024-01-222024-01-222020Vilela, C.; Morais, J.D.; Silva, A.C.Q.; Muñoz-Gil, D.; Figueiredo, F.M.L.; Silvestre, A.J.D.; Freire, C.S.R. Flexible Nanocellulose/Lignosulfonates Ion-Conducting Separators for Polymer Electrolyte Fuel Cells. Nanomaterials 2020, 10, 1713. https://doi.org/10.3390/nano100917132079-499110.3390/nano10091713https://hdl.handle.net/20.500.14352/94303The utilization of biobased materials for the fabrication of naturally derived ion-exchange membranes is breezing a path to sustainable separators for polymer electrolyte fuel cells (PEFCs). In this investigation, bacterial nanocellulose (BNC, a bacterial polysaccharide) and lignosulfonates (LS, a by-product of the sulfite pulping process), were blended by diffusion of an aqueous solution of the lignin derivative and of the natural-based cross-linker tannic acid into the wet BNC nanofibrous three-dimensional structure, to produce fully biobased ion-exchange membranes. These freestanding separators exhibited good thermal-oxidative stability of up to about 200 °C, in both inert and oxidative atmospheres (N2 and O2, respectively), high mechanical properties with a maximum Young’s modulus of around 8.2 GPa, as well as good moisture-uptake capacity with a maximum value of ca. 78% after 48 h for the membrane with the higher LS content. Moreover, the combination of the conducting LS with the mechanically robust BNC conveyed ionic conductivity to the membranes, namely a maximum of 23 mS·cm–1 at 94 °C and 98% relative humidity (RH) (inplane configuration), that increased with increasing RH. Hence, these robust water-mediated ion conductors represent an environmentally friendly alternative to the conventional ion-exchange membranes for application in PEFCs.engjournal articlehttps://doi.org/10.3390/nano10091713open access546Bacterial nanocelluloseLignosulfonatesMechanical performanceThermal-oxidative stabilityIon-exchange membranesBiobased separatorsIonic conductivityQuímica inorgánica (Química)23 Química