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Abstract: A cobalt-free cubic perovskite oxide SrFe0.9Sb0.1O3−δ (SFSb) is investigated as a novel cathode for proton-conducting solid oxide fuel cells (H-SOFCs). XRD results show that SFSb cathode is chemically compatible with the electrolyte BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) for temperatures up to 1000°C. Thin proton-conducting BZCYYb electrolyte and NiO–BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (NiO–BZCYYb) anode functional layer are prepared over porous anode substrates composed of NiO–BZCYYb by a one-step dry-pressing/co-firing process. Laboratory-sized quad-layer cells of NiO–BZCYYb/NiO–BZCYYb/BZCYYb/SFSb are operated from 550 to 700°C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. An open-circuit potential of 0.996V, maximum power density of 428mWcm−2, and a low electrode polarization resistance of 0.154Ωcm2 are achieved at 700°C. The experimental results indicate that the cobalt-free SFSb is a promising candidate for cathode material for H-SOFCs. [Copyright &y& Elsevier]

Abstract: A novel cobalt-free perovskite oxide Ba0.5Sr0.5Fe0.8Cu0.2O3−δ (BSFC) is employed as a cathode material for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The electrical conductivity of BSFC reaches the maximum value of 57Scm−1 at 600°C. Symmetrical electrochemical cell with the configuration of BSFC/SDC/BSFC is applied for the impedance study and area specific resistance (ASR) of BSFC cathode material is as low as 0.137Ωcm2 at 700°C. The single cell, consisting of BSFC/SDC/NiO–SDC structure, is assembled and tested from 550 to 700°C with humidified hydrogen (∼3% H2O) as the fuel and the static air as the oxidant. A maximum power density of 718mWcm2 is obtained at 700°C for the single cell. Preliminary results demonstrate that the cobalt-free oxide BSFC is a very promising cathode material for application in IT-SOFCs. [Copyright &y& Elsevier]

Abstract: A cobalt-free composite Sm0.5Sr0.5Fe0.8Cu0.2O3−δ –Ce0.8Sm0.2O2−δ (SSFCu–SDC) is investigated as a cathode for proton-conducting solid oxide fuel cells (H-SOFCs) in intermediate temperature range, with BaZr0.1Ce0.7Y0.1Yb0.1O3−δ (BZCYYb) as the electrolyte. The XRD results show that SSFCu is chemically compatible with SDC at temperatures up to 1100°C. The quad-layer single cells of NiO–BZCYYb/NiO–BZCYYb/BZCYYb/SSFCu–SDC are operated from 500 to 700°C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. It shows an excellent power density of 505mWcm−2 at 700°C. Moreover, a low electrode polarization resistance of 0.138Ωcm2 is achieved at 700°C. Preliminary results demonstrate that the cobalt-free SSFCu–SDC composite is a promising cathode material for H-SOFCs. [Copyright &y& Elsevier]

Abstract: Nano-sized Ce0.79Gd0.2Cu0.01O2−δ electrolyte powder was synthesized by the polyvinyl alcohol assisted combustion method, and then characterized by crystalline structure, powder morphology, sintering micro-structure and electrical properties. The results demonstrate that the as-synthesized Ce0.79Gd0.2Cu0.01O2−δ was well crystalline with cubic fluorite structure, and exhibited a porous foamy morphology composed of gas cavities and fine crystals ranging from 30 to 50nm. After sintering at 1100°C, the as-prepared pellets exhibited a dense and moderate-grained micro-structure with 95.54% relative density, suggesting that the synthesized Ce0.79Gd0.2Cu0.01O2−δ powder had high sintering activity. The powders made by this method are expected to offer potential application in intermediate-to-low temperature solid-oxide fuel cells, due to its very low densification sintering temperature (1100°C), as well as high conductivity of 0.026Scm−1 at 600°C and good mechanical performance with three-point flexural strength value of 148.15±2.42MPa. [Copyright &y& Elsevier]

Abstract: The perovskite La0.6Sr0.4Co0.8Cu0.2O3−δ (LSCCu) oxide is synthesized by a modified Pechini method and examined as a novel cathode material for low-temperature solid oxide fuel cells (LT-SOFCs) based upon functional graded anode. The perovskite LSCCu exhibits excellent ionic and electronic conductivities in the intermediate-to-low-temperature range (400–800°C). Thin Sm0.2Ce0.8O1.9 (SDC) electrolyte and NiO–SDC anode functional layer are prepared over macroporous anode substrates composed of NiO–SDC by a one-step dry-pressing/co-firing process. A single cell with 20μm thick SDC electrolyte on a porous anode support and LSCCu–SDC cathode shows peak power densities of only 583.2mWcm−2 at 650°C and 309.4mWcm−2 for 550°C. While a cell with 20μm thick SDC electrolyte and an anode functional layer on the macroporous anode substrate shows peak power densities of 867.3 and 490.3mWcm−2 at 650 and 550°C, respectively. The dramatic improvement of cell performance is attributed to the much improved anode microstructure that is confirmed by both SEM observation and impedance spectroscopy. The results indicate that LSCCu is a very promising cathode material for LT-SOFCs and the one-step dry-pressing/co-firing process is a suitable technique to fabricate high performance SOFCs. [Copyright &y& Elsevier]

Abstract: The perovskite-type Ba0.5Sr0.5Co0.8Fe0.2O3-δ–BaZr0.1Ce0.7Y0.2O3-δ (BSCF–BZCY) composite oxides were synthesized by a modified Pechini method and examined as a novel composite cathode for intermediate-to-low temperature protonic ceramic membrane fuel cells (ILT-PCMFCs). Thin proton-conducting BaZr0.1Ce0.7Y0.2O3-δ (BZCY) electrolyte and NiO–BaZr0.1Ce0.7Y0.2O3-δ (NiO–BZCY) anode functional layer were prepared over porous anode substrates composed of NiO–BaZr0.1Ce0.7Y0.2O3-δ by a one-step dry-pressing/co-firing process. A laboratory-sized quad-layer cell of NiO–BZCY/NiO–BZCY(∼50μm)/BZCY(∼20μm)/BSCF–BZCY(∼50μm) was operated from 550 to 700°C with humidified hydrogen (∼3% H2O) as fuel and the static air as oxidant. A high open-circuit potential of 1.009V, a maximum power density of 418mWcm−2, and a low polarization resistance of the electrodes of 0.10Ωcm2 was achieved at 700°C. These investigations have indicated that proton-conducting BZCY electrolyte with BSCF perovskite cathode is a promising material system for the next generation solid oxide fuel cells (SOFCs). [Copyright &y& Elsevier]