Solid oxide fuel cells (SOFCs) represent the most efficient devices for producing electrical power from fuels. The limit in their application is due to the high operation temperature of conventional SOFC materials. Progress is made toward lower operating temperatures using alternative oxygen-ion conducting electrolytes, but problems of stability and electronic conductivity still remain. A promising alternative is the use of chemically stable proton-conducting Y-doped BaZrO3 (BZY) electrolytes, but their practical applications are limited by the BZY's relatively low performance. Herein, it is reported that deposition by impregnation of cathode nanoparticles on BZY backbones provides a powerful strategy to improve the BZY-based SOFC performance below 600 °C, allowing an outstanding power output for this chemically stable electrolyte. Moreover, it is demonstrated that keeping the nanostructure is more important than keeping the desired chemical composition. The proposed scalable processing method can make BZY a competitive electrolyte for SOFC applications.

Tailoring the Cathode-Electrolyte Interface with Nanoparticles for Boosting the Solid Oxide Fuel Cell Performance of Chemically Stable Proton-Conducting Electrolytes.

Cation deficiency in perovskite oxides can alter the crystal structure, oxygen stoichiometry and other physiochemical properties, substantially promote the electro-catalytic activity for oxygen reduction reaction (ORR) at elevated temperatures. In this work, a small strontium deficiency was introduced into SrCo0.8Nb0.1Ta0.1O3-δ (S100CNT) to promote the electrochemical activity of ORR. Cation deficient Sr0.95Co0.8Nb0.1Ta0.1O3-δ (S095CNT) displayed higher oxygen vacancy concentration than that of stoichiometric S100CNT. The decreased average bonding energy (ABE) and the increased critical radius (rc) of S095CNT could be responsible for the decreased activation energy for oxygen ions transfer. Consequently, the ORR activity of S095CNT cathode was significantly improved. The S095CNT cathode shows an area specific resistance of 0.07 Ω cm2 at 650 °C, which was only about 63% of S100CNT. Moreover, S095CNT displayed much higher CO2 tolerance than the state-of-the-art Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) cathode for SOFC. Thus, the fast ORR and high stability makes S095CNT promising material for devices involving oxygen electrochemistry such as solid oxide fuel cells, electrolysis cells, or gas separation membranes.

Cation deficiency enabled fast oxygen reduction reaction for a novel SOFC cathode with promoted CO2 tolerance

A bi-functional Co–CaO–Ca12Al14O33 catalyst for sorption-enhanced steam reforming of glycerol to high-purity hydrogen

Cobaltite oxide nanosheets anchored graphene nanocomposite as an efficient oxygen reduction reaction (ORR) catalyst for the application of lithium-air batteries

Preferred crystallographic orientation, i.e. texture in crystalline materials powder diffraction data, can cause serious systematic errors in phase composition analysis and also in crystal structure determination. The March model [Dollase (1986). J. Appl. Cryst. 19, 267–272] has been used widely in Rietveld refinement for correcting powder diffraction intensities with respect to the effects of preferred orientation. In the present study, a comparative evaluation of the March model and the generalized spherical harmonic [Von Dreele (1997). J. Appl. Cryst. 30, 517–525] description for preferred orientation was performed with X-ray powder diffraction data for molybdite (MoO3) and calcite (CaCO3) powders uniaxially pressed at five different pressures. Additional molybdite and calcite powders, to which 50% by weight silica gel had been added, were prepared to extend the range of preferred orientations considered. The patterns were analyzed initially assuming random orientation of the crystallites and subsequently the March model was used to correct the preferred orientation. The refinement results were compared with parallel refinements conducted with the generalized spherical harmonic [Sitepu (2002). J. Appl. Cryst. 35, 274–277]. The results obtained show that the generalized spherical harmonic description generally provided superior figures-of-merit compared with the March model results.

Comparative evaluation of the March and generalized spherical harmonic preferred orientation models using X-ray diffraction data for molybdite and calcite powders Note: March model Locality: synthetic

Effect of calcination temperature on oxidation state of cobalt in calcium cobaltite and relevant performance as intermediate-temperature solid oxide fuel cell cathodes

Dense thin YSZ electrolyte films prepared by a vacuum slurry deposition technique for SOFCs

Investigation of La 1−x Sm x−y Sr y CoO 3−δ cathode for intermediate temperature solid oxide fuel cells

Optimization of electrochemical performance of Ca3Co2O6 cathode on yttria-stabilized zirconia electrolyte for intermediate temperature solid oxide fuel cells

Shancheng Yu

Papers

Effect of calcination temperature on oxidation state of cobalt in calcium cobaltite and relevant performance as intermediate-temperature solid oxide fuel cell cathodes

Dense thin YSZ electrolyte films prepared by a vacuum slurry deposition technique for SOFCs

Investigation of La 1−x Sm x−y Sr y CoO 3−δ cathode for intermediate temperature solid oxide fuel cells

Optimization of electrochemical performance of Ca3Co2O6 cathode on yttria-stabilized zirconia electrolyte for intermediate temperature solid oxide fuel cells

Performance enhancement for solid oxide fuel cells using electrolyte surface modification