Fillers based on Yttria-Stabilized Zirconium oxide (YSZ) have been extensively studied for composite membranes development in Polymer Electrolyte Fuel Cells (PEFCs), in particular Y2O3 8mol.% [1] content permit to operate at higher T and reduced RH. On basis of a previous study [2-3], a cubic-ZrO2 was synthesised using pure ZrO2 [4] and c-Y2O3 as cubic phase inductor. Syn-YSZ fillers varying the Y2O3 loadings (4.8, 8, 12, 15mol.%) in YSZ were synthesised to verify the doping influence on membranes characteristics. Such fillers were used to prepare composite based-Nafion membranes with an optimised 5wt.% of filler [2] and casting procedure [5]: NYSZ4.8, NYSZ8, NYSZ12, NYSZ15. Pure Nafion (Nrecast) was used as reference. The chemical-physical characterisation on membranes was performed (water retention, IEC, BET, XRD, TG, DMA, SEM) [3]. Also, the oxidative stability by Fenton's tests, as DoE suggests, was investigated verifying the filler ability to protect from degradation phenomenon. Proton conductivity (PC) at reduced RH and the electrochemical performance (I-V curves, Accelerated Degradation Test-ADT, H2cross-over) in drastic conditions were studied. For ADT, the samples were stressed between 0.1-0.4 Acm-2 up to performance failure/significant performance decrease. PC at reduced RH supplied high values at Tc=100-120°C for films with the highest Y2O3 loads (12-15mol.%) confirming intrinsic YSZ proton conductivity. The composite membranes proved to be more resistant in terms of oxidative stability, provided higher durability and cycles number with reduced H2crossover (here named H2-CrO) increase (119 vs. 95 cycles in ADT). NYSZ12 sample seems to represent the best candidate for final application due to its durability within DoE targets, H2 crossover (EoT). Table 1 presents the main results. Table 1.Main ADT and H2 crossover results. References [1]T.Weissbach, T.J. Peckham, S. Holdcroft, J. Membr. Sci. 498 (2016) 94-104 [2]A.Saccà, A.Carbone, I.Gatto, R.Pedicini, E. Passalacqua, Polymer Testing 65 322 (2018) 322-330 [3]A.Saccà,A.Carbone,I.Gatto,A.K.Sahu,S.D.Bhat,E.Passalacqua, ANM2017 Aveiro (Portugal) July 2017 [4]N.A.Comelli, L.M.Grzona, O.Masini, E.N.Ponzia. M.I.Ponzi, J. Chil. Chem. Soc. 49(3) (2004) 245-250 [5]A.Alvarez, C.Guzman, A.Carbone, A.Saccà, I.Gatto, E.Passalacqua, R.Nava, R.Ornelas, J.Ledesma-Garcia, L.G.Arriaga, Int. J. Hydrogen Energy 36 (2011) 14725-14733
Development of Composite Nafion-YSZ Membranes with Improved Stability for drastic conditions in PEFCs
A Carbone;R Pedicini;I Gatto;E Passalacqua
2019
Abstract
Fillers based on Yttria-Stabilized Zirconium oxide (YSZ) have been extensively studied for composite membranes development in Polymer Electrolyte Fuel Cells (PEFCs), in particular Y2O3 8mol.% [1] content permit to operate at higher T and reduced RH. On basis of a previous study [2-3], a cubic-ZrO2 was synthesised using pure ZrO2 [4] and c-Y2O3 as cubic phase inductor. Syn-YSZ fillers varying the Y2O3 loadings (4.8, 8, 12, 15mol.%) in YSZ were synthesised to verify the doping influence on membranes characteristics. Such fillers were used to prepare composite based-Nafion membranes with an optimised 5wt.% of filler [2] and casting procedure [5]: NYSZ4.8, NYSZ8, NYSZ12, NYSZ15. Pure Nafion (Nrecast) was used as reference. The chemical-physical characterisation on membranes was performed (water retention, IEC, BET, XRD, TG, DMA, SEM) [3]. Also, the oxidative stability by Fenton's tests, as DoE suggests, was investigated verifying the filler ability to protect from degradation phenomenon. Proton conductivity (PC) at reduced RH and the electrochemical performance (I-V curves, Accelerated Degradation Test-ADT, H2cross-over) in drastic conditions were studied. For ADT, the samples were stressed between 0.1-0.4 Acm-2 up to performance failure/significant performance decrease. PC at reduced RH supplied high values at Tc=100-120°C for films with the highest Y2O3 loads (12-15mol.%) confirming intrinsic YSZ proton conductivity. The composite membranes proved to be more resistant in terms of oxidative stability, provided higher durability and cycles number with reduced H2crossover (here named H2-CrO) increase (119 vs. 95 cycles in ADT). NYSZ12 sample seems to represent the best candidate for final application due to its durability within DoE targets, H2 crossover (EoT). Table 1 presents the main results. Table 1.Main ADT and H2 crossover results. References [1]T.Weissbach, T.J. Peckham, S. Holdcroft, J. Membr. Sci. 498 (2016) 94-104 [2]A.Saccà, A.Carbone, I.Gatto, R.Pedicini, E. Passalacqua, Polymer Testing 65 322 (2018) 322-330 [3]A.Saccà,A.Carbone,I.Gatto,A.K.Sahu,S.D.Bhat,E.Passalacqua, ANM2017 Aveiro (Portugal) July 2017 [4]N.A.Comelli, L.M.Grzona, O.Masini, E.N.Ponzia. M.I.Ponzi, J. Chil. Chem. Soc. 49(3) (2004) 245-250 [5]A.Alvarez, C.Guzman, A.Carbone, A.Saccà, I.Gatto, E.Passalacqua, R.Nava, R.Ornelas, J.Ledesma-Garcia, L.G.Arriaga, Int. J. Hydrogen Energy 36 (2011) 14725-14733I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
