scholarly journals New two-layer Ruddlesden—Popper cathode materials for protonic ceramics fuel cells

2021 ◽  
Author(s):  
Yihan Ling ◽  
Tianming Guo ◽  
Yangyang Guo ◽  
Yang Yang ◽  
Yunfeng Tian ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Frequency ◽  
Single Phase ◽  
Composite Cathode ◽  
Electrode Polarization ◽  
High Power Density ◽  
Ni Doping ◽  
High Frequency Region ◽  
X Ray ◽  
Electrode Interface

AbstractNew two-layer Ruddlesden—Popper (RP) oxide La0.25Sr2.75FeNiO7−δ (LSFN) in the combination of Sr3Fe2O7−δ and La3Ni2O7−δ was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells (PCFCs). LSFN with the tetragonal symmetrical structure (I4/mmm) is confirmed, and the co-existence of Fe3+/Fe4+ and Ni3+/Ni2+ couples is demonstrated by X-ray photoelectron spectrometer (XPS) analysis. The LSFN conductivity is apparently enhanced after Ni doping in Fe-site, and nearly three times those of Sr3Fe2O7−δ, which is directly related to the carrier concentration and conductor mechanism. Importantly, anode supported PCFCs using LSFN-BaZr0.1Ce0.7Y0.2O3−δ (LSFN-BZCY) composite cathode achieved high power density (426 mW·cm−2 at 650 °C) and low electrode interface polarization resistance (0.26 Ω·cm2). Besides, distribution of relaxation time (DRT) function technology was further used to analyse the electrode polarization processes. The observed three peaks (P1, P2, and P3) separated by DRT shifted to the high frequency region with the decreasing temperature, suggesting that the charge transfer at the electrode-electrolyte interfaces becomes more difficult at reduced temperatures. Preliminary results demonstrate that new two-layer RP phase LSFN can be a promising cathode candidate for PCFCs.

New Two-layer Ruddlesden-popper Cathode Materials for Protonic Ceramics Fuel Cells

2021 ◽  
Author(s):  
Y.H. Ling ◽  
Yihan Ling ◽  
Tianming Guo ◽  
Yangyang Guo ◽  
Yang Yang ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Frequency ◽  
Single Phase ◽  
Composite Cathode ◽  
Electrode Polarization ◽  
Ni Doping ◽  
Relaxation Time Distribution ◽  
High Frequency Region ◽  
Electrode Interface ◽  
Reduced Temperature

Abstract New two-layer Ruddlesden-popper (RP) oxide La0.25Sr2.75FeNiO7-δ (LSFN) in the combination of Sr3Fe2O7-δ and La3Ni2O7-δ was successfully synthesized and studied as the potential active single-phase and composite cathode for protonic ceramics fuel cells (PCFCs). LSFN with the tetragonal symmetrical structure (I4/mmm) is confirmed, and the co-existence of Fe3+ /Fe4+ and Ni3+/Ni2+ couples is demonstrated by XPS analysis. The LSFN conductivity is apparently enhanced after Ni doping in Fe-site, and nearly three times those of Sr3Fe2O7-δ, which is directly related to the carrier concentration and conductor mechanism. Importantly, anode supported PCFCs using LSFN-BZCY composite cathode achieved high power density (426 mW·cm-2 at 650°C) and low electrode interface polarization resistance (0.26 Ω cm2). Besides, relaxation time distribution function (DRT) technology was further used to analysis the electrode polarization processes. The observed three peaks (P1, P2, P3) separated by DRT shifted to the high frequency region with the decreasing temperature, suggesting that the charge transfer at the electrode-electrolyte interfaces become more difficult at reduced temperature. Preliminary results demonstrate new two-layer PR phase LSFN can be a promising cathode candidate for PCFCs.

Intermetallic Cerium Compounds with Ordered U3Si2 Type Structure

2000 ◽  
Vol 55 (2) ◽  
pp. 155-161 ◽  
Author(s):  
Rainer Pöttgen ◽  
Artur Fugmann ◽  
Rolf-Dieter Hoffmann ◽  
Ute Ch. Rodewald ◽  
Dirk Niepmann
Keyword(s):  
Thermal Treatment ◽  
Homogeneity Range ◽  
High Frequency ◽  
Single Phase ◽  
Type Structure ◽  
Crystal Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Full Occupancy ◽  
Cerium Compounds

Abstract New intermetallic cerium compounds Ce2T2Mg (T = Ni, Cu, Pd), C2T2Cd (T=Pd, Pt, Au), and C2T2Pb (T = Pt, Au) were prepared by reaction of the elements in sealed tantalum tubes in a high-frequency furnace. Most C2T2X (X = Mg, Cd, Pb) compounds are stable after annealing at about 1000 K, while Ce2Pd2Mg is obtained as single phase only after melting and quenching. A thermal treatment at about 1000 K leads to decomposition in CePdMg and CePd. The eight compounds were investigated by X-ray diffraction both as powders and single crystals, and most structures were refined from single crystal data. They adopt an ordered U3Si2 type structure with space group P4/mbm: a = 759.6(1), c = 376.71 (9) pm, wR2 = 0.0562, 294 F2 values, 12 parameters for Ce2Ni2Mg, a = 787.41(9), c = 387.23(7) pm, wR2 = 0.0438, 222 F2 values, 12 parameters for Ce2Cu2Mg, a = 777.14(8), c = 400.03(7) pm, wR2 = 0.0276, 221 F2 values, 13 parameters for Ce2Pd2.03Mg0.97, a = 777.90(6), c = 393.28(6) pm, wR2 = 0.0360,317 F2 values, 12 parameters for Ce2Pd2Cd, and a = 779.90(7), c = 389.97(7) pm, wR2 = 0.0453, 315 F2 values, 12 parameters for Ce2Pt2Cd. Refinement of the occupancy parameters revealed full occupancy for most sites. A mixed palladium/magnesium (97 % Mg / 3 % Pd) occupancy was observed only for the 2a site of Ce2Pd2.03Mg0.97, indicating a small homogeneity range for this compound. Ce2Au2Cd (a = 804.93(7), c =393.36(6) pm) and the plumbides Ce2Pt2Pb (a = 794.63(7), c = 381.50(6) pm) and Ce2Au2Pb (a = 810.70(7), c = 394.85(7) pm) were characterized through their Guinier powder data. The structures of the Ce2T2X compounds can be interpreted as an intergrowth of distorted AIB2 and CsCl related slabs of compositions CeT2 and CeX. The course of the lattice parameters and chemical bonding within the series of Ce2T2X compounds are briefly discussed.

scholarly journals High-Performance La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ Cathode Composites via an Exsolution Mechanism for Protonic Ceramic Fuel Cells

Inorganics ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 83 ◽  
Author(s):  
Laura Rioja-Monllor ◽  
Sandrine Ricote ◽  
Carlos Bernuy-Lopez ◽  
Tor Grande ◽  
Ryan O’Hayre ◽  
...  
Keyword(s):  
Fuel Cells ◽  
High Performance ◽  
Single Phase ◽  
Composite Cathode ◽  
Nominal Composition ◽  
Composite Cathodes ◽  
Phase Precursor ◽  
Ceramic Fuel ◽  
Two Phases ◽  
Ceramic Fuel Cells

A novel exsolution process was used to fabricate complex all-oxide nanocomposite cathodes for Protonic Ceramic Fuel Cells (PCFCs). The nanocomposite cathodes with La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr1−zYzO3−δ nominal composition were prepared from a single-phase precursor via an oxidation-driven exsolution mechanism. The exsolution process results in a highly nanostructured and intimately interconnected percolating network of the two final phases, one proton conducting (BaZr1−zYzO3−δ) and one mixed oxygen ion and electron conducting (La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ), yielding excellent cathode performance. The cathode powder is synthesized as a single-phase cubic precursor by a modified Pechini route followed by annealing at 700 °C in N2. The precursor phase is exsolved into two cubic perovskite phases by further heat treatment in air. The phase composition and chemical composition of the two phases were confirmed by Rietveld refinement. The electrical conductivity of the composites was measured and the electrochemical performance was determined by impedance spectroscopy of symmetrical cells using BaZr0.9Y0.1O2.95 as electrolyte. Our results establish the potential of this exsolution method where a large number of different cations can be used to design composite cathodes. The La0.5Ba0.5Co1/3Mn1/3Fe1/3O3−δ-BaZr0.9Y0.1O2.95 composite cathode shows the best performance of 0.44 Ω∙cm2 at 600 °C in 3% moist synthetic air.

scholarly journals Structural and vibrational spectroscopic studies of new phases with sillenite type in the system Bi2O3- In2O3 –MgO

2020 ◽  
Vol 10 (1) ◽  
pp. 90-98
Author(s):  
Hajar Ait Oulahyane ◽  
Abdeslam Chagraoui ◽  
Leila Loubbidi ◽  
Lamia Bourja ◽  
Omar Ait Sidi Ahmed ◽  
...  
Keyword(s):  
High Frequency ◽  
Lone Pair ◽  
Rietveld Analysis ◽  
Spectroscopic Studies ◽  
Frequency Region ◽  
Family Type ◽  
X Ray Diffraction ◽  
High Frequency Region ◽  
X Ray ◽  
Full Profile

The anion and cation deficient phase Bi0.95 In0.05 O1.5 (Bi1.9 In0.1 O3) was synthesized and experimentally investigated using X-ray diffraction and vibrational spectroscopy (Infrared and Raman). The non-stoichiometric phases are similar to sillenite family type γBi2O3 and crystallize in the I23 space group. The crystal structure was determined by full profile Rietveld analysis of the powder diffractogram. It is formed by a sequence of BiO5E polyhedra (E lone pair of bismuth) and MO4 polyhedra (M = In, Mg). The set of MO4 polyhedra are localized in cavities generated by BiO5E polyhedra. The vibrational spectroscopic study revealed the existence of three regions; low, intermediate and high-frequency region. They are attributed to Bi-O stretching mode, In / Mg-O vibrations and cationic displacements respectively.

COMPARISON OF SINGLE-PHASE AND HIGH-FREQUENCY GENERATORS FOR X-RAY UNITS

2002 ◽  
Vol 43 (2) ◽  
pp. 118-122 ◽  
Author(s):  
P.Y. Barthez ◽  
N. Manwaring ◽  
P.M. Mitelmann ◽  
E. Benoit
Keyword(s):  
High Frequency ◽  
Single Phase ◽  
X Ray

scholarly journals Composite Cathode for High-Power Density Solid Oxide Fuel Cells

2004 ◽  
Author(s):  
Ilwon Kim ◽  
Scott Barnett ◽  
Yi Jiang ◽  
Manoj Pillai ◽  
Nikkia McDonald ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Solid Oxide Fuel Cells ◽  
Power Density ◽  
High Power ◽  
Composite Cathode ◽  
Solid Oxide ◽  
High Power Density ◽  
Oxide Fuel

XANES STUDY OF Ni-DOPED Bi-Ca-Sr-Cu-O SYSTEM

1990 ◽  
Vol 04 (17) ◽  
pp. 1083-1088 ◽  
Author(s):  
K.V.R. RAO ◽  
P. SRIVASTAVA ◽  
B.R. SEKHAR ◽  
K.B. GARG ◽  
S.K. AGARWAL ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Single Phase ◽  
Partial Substitution ◽  
Progressive Decrease ◽  
Ni Doping ◽  
X Ray ◽  
Xrd Patterns ◽  
X Ray Absorption ◽  
Absorption Measurements

We report the results of X-ray absorption measurements on partial substitution of Ni in place of Cu in Bi 2 Ca 1 Sr 2 Cu 2−x Ni x O y with x varying from 0 to 10 at %. The XRD patterns of the samples confirm their single phase nature. The transition temperature Tc decreases monotonically with Ni doping and the rate of decrease of Tc is around 2.5 K at % of the nominal substitution. The XANES results show that Ni is incorporated in the lattice with Ni-O bonds substituting for Cu-O bonds. The progressive decrease in the ratio of Cu 2+/ Cu 1+ is examined.

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