resumo
The 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 degrees C, in both inert and oxidative atmospheres (N(2)and O-2, 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 degrees C and 98% relative humidity (RH) (in-plane 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.
palavras-chave
NANOCOMPOSITE MEMBRANES; PROTONIC CONDUCTIVITY; COMPOSITE MEMBRANES; NANOCELLULOSE; LIGNIN; MECHANISMS; TRANSPORT; NAFION(R)
categoria
Science & Technology - Other Topics; Materials Science
autores
Vilela, C; Morais, JD; Silva, ACQ; Munoz-Gil, D; Figueiredo, FML; Silvestre, AJD; Freire, CSR
nossos autores
Ana Cristina Quintans da Silva
Estudante de doutoramento
Armando Jorge Domingues Silvestre
Professor Catedrático
Carla Vilela
Professor Auxiliar
Carmen Sofia da Rocha Freire Barros
Investigador Coordenador
Daniel Muñoz Gil
Bolseiro de pós-Doutoramento
Filipe Miguel H Lebre R Figueiredo
Investigador PrincipalGrupos
G1 - Materiais Porosos e Nanossistemas
G3 - Materiais Eletroquímicos, Interfaces e Revestimentos
G4 - Materiais Renováveis e Economia Circular
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology (FCT)/MCTES. FCT is also acknowledged for the doctoral grant to A.C.Q.S. (SFRH/BD/140230/2018) and the research contract under Scientific Employment Stimulus to C.V. (CEECIND/00263/2018). Additional funding to D.M.G. and F.M.L.F. through project UniRCell (SAICTPAC/0032/2015, POCI-01-0145-FEDER-016422) co-financed by FCT/MEC and FEDER under the PT2020 Partnership Agreement.