Fabrication and characterisation of a large-area solid oxide fuel cell based on dual tape cast YSZ electrode skeleton supported YSZ electrolytes with vanadate and ferrite perovskite-impregnated anodes and cathodes

The authors thank the U.S. Office of Naval Research for support for this collaboration. CSN and JTSI also thank EPSRC (UK) for support. JTSI thanks the Royal Society for support.Infiltration of ceramic materials into a pre-formed ceramic scaffold is an effective way of fabricating a solid oxide fuel cell with nano-structured ceramic electrodes by avoiding detrimental interfacial reactions through low-temperature processing for achieving high performance using hydrogen as well as a carbonaceous fuel. However, there are significant concerns about the applicability of this method because of the difficulty in fabricating a large-area gas-tight but thin electrolyte between two highly porous ceramic and the multiple repetitions of infiltration process. Here, a large-area (5 cm by 5 cm) scaffold with a thin yttria-stabilized zirconia (YSZ) electrolyte sandwiched between two identical porous structures is prepared by tape casting and co-firing, and then solution precursors are impregnated into the porous scaffolds to prepare nano-structured La0.8Sr0.2FeO3 (LSF) and La0.7Sr0.3VO3−δ (LSVred). The thus prepared solid oxide fuel cell with 10 wt% ceria + 1 wt% Pd as a catalyst in anodes shows a peak power of 489 mW cm−2 (~6 W per cell) at 800 °C using H2 as a fuel and air as an oxidant. This large-area fuel cell retained the integrity of the thin electrolyte and high performance after the reducing-oxidation cycle at 900 °C, showing superiority over the conventional Ni(O)-YSZ based support.PostprintPeer reviewe

Synthesis of highly porous yttria-stabilized zirconia by tape-casting methods

Porous ceramics of Y2O3-stabilized ZrO2 (YSZ) were prepared by tape-casting methods using both pyrolyzable pore formers and NiO followed by acid leaching. The porosity of YSZ wafers increased in a regular manner with the mass of graphite or polymethyl methacrylate (PMMA) to between 60% and 75% porosity. SEM indicated that the shape of the pores in the final ceramic was related to the shape of the pore formers, so that the pore size and microstructure of YSZ wafers could be controlled by the choice of pore former. Dilatometry measurements showed that measurable shrinkage started at 1300 K, and a total shrinkage of 26% was observed, independent of the amount or type of pore former used. Temperature-programmed oxidation (TPO) measurements on the green tapes demonstrated that the binders and dispersants were combusted between 550 and 750 K, that PMMA decomposed to methyl methacrylate between 500 and 700 K, and that graphite combusted above 900 K. The porosity of YSZ ceramics prepared by acid leaching of nickel from NiO\u2013YSZ, with 50 wt% NiO, was studied as a function of NiO and YSZ particle size. Significant changes in pore dimension were found when NiO particle size was changed

Fabrication and characterisation of a large-area solid oxide fuel cell based on dual tape cast YSZ electrode skeleton supported YSZ electrolytes with vanadate and ferrite perovskite-impregnated anodes and cathodes

Infiltration of ceramic materials into a pre-formed ceramic scaffold is an effective way of fabricating a solid oxide fuel cell with nano-structured ceramic electrodes by avoiding detrimental interfacial reactions through low-temperature processing for achieving high performance using hydrogen as well as a carbonaceous fuel. However, there are significant concerns about the applicability of this method because of the difficulty in fabricating a large-area gas-tight but thin electrolyte between two highly porous ceramic and the multiple repetitions of infiltration process. Here, a large-area (5 cm by 5 cm) scaffold with a thin yttria-stabilized zirconia (YSZ) electrolyte sandwiched between two identical porous structures is prepared by tape casting and co-firing, and then solution precursors are impregnated into the porous scaffolds to prepare nano-structured La0.8Sr0.2FeO3 (LSF) and La0.7Sr0.3VO3−δ (LSVred). The thus prepared solid oxide fuel cell with 10 wt% ceria + 1 wt% Pd as a catalyst in anodes shows a peak power of 489 mW cm−2 (~6 W per cell) at 800 °C using H2 as a fuel and air as an oxidant. This large-area fuel cell retained the integrity of the thin electrolyte and high performance after the reducing-oxidation cycle at 900 °C, showing superiority over the conventional Ni(O)-YSZ based support.</p

Fabrication of highly porous yttria-stabilized zirconia by acid leaching nickel from a nickel-yttria-stabilized zirconia cermet

Porous Y2O3-stabilized ZrO2 (YSZ) samples were synthesized by preparing NiO/YSZ composites by tape casting and calcining at 1800 K, reducing the NiO to nickel in H2 at 973 K, and finally leaching the nickel out of the structure with 2.2M HNO3 at 353 K. Porous YSZ was prepared from NiO/YSZ composites containing 0, 20, 40, and 50 wt% NiO. Complete removal of the nickel was demonstrated by XRD, weight changes, and porosity increases. Porosities >75% could be achieved without structural collapse of the YSZ phase. Finally, the method was applied to the fabrication of a solid oxide fuel cell with a copper-based anode operating on H2 and n-butane