Characterization of Novel Perovskite-Type La0.6Sr0.2Ca0.2Co1-YFeYO3-δ Cathode Materials Prepared by Solid State Reaction for IT-SOFCs

Perovskite-type cathode materials La0.6Sr0.2Ca0.2Co1-yFeyO3-δ(0.2≤y≤0.5, marked as LSCCF62282, LSCCF62273, LSCCF62264 and LSCCF62255) for intermediate-temperature solid oxide fuel cells (IT-SOFCs) were prepared by solid state reaction. The establishment process and phase transformation were measured by TG-DTA, FT/IR and XRD techniques. Single hexagonal perovskite phase can be achieved after sintered at 1100 °C for 3 h. Mixed conductivity, thermal expansion behavior and chemical stability of sintered samples at 1100 °C for 3 h have been investigated. At intermediate temperature (600-800 °C), the mixed conductivity characterized by DC four-probe technique is higher than 100 S/cm. LSCCF62282 has the highest conductivity of 297.3 S/cm at 700 °C among the four samples. At lower temperatures, the conductivity follows small polaron hopping mechanism. Thermal expansion coefficients (TECs) of the samples from 50 °C to 850 °C exhibit a reducing tendency with increasing amount of doped Fe3+. Thermal expansion behavior can be improved by doping with Ca2+and Fe3+commonly. XRD pattern for LSCCF62282 and YSZ mixture sintered at 800 °C for 6h indicates that cathode material LSCCF62282 is chemically stable against YSZ electrolyte at operating temperature.

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Investigation on Preparation and Electrical Properties of Novel Perovskite Cathode Materials Doped with Multi-Elements for IT-SOFC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.532-533.35 ◽

2012 ◽

Vol 532-533 ◽

pp. 35-39

Author(s):

Jie Zhao ◽

Ling Long Kong ◽

Chen Li ◽

Yong Chang Ma

Keyword(s):

Cathode Materials ◽

Oxygen Vacancies ◽

Small Polaron ◽

Negative Temperature ◽

Intermediate Temperature ◽

Charge Balance ◽

Mixed Conductivity ◽

Polaron Hopping ◽

Lower Temperature ◽

Perovskite Type

To develop novel cathode materials with high electrical performances for intermediate temperature solid oxide fuel cells (IT-SOFCs) and optimize the preparation process, perovskite-type oxides Pr1-x-ySrxCayCo1-zFezO3-δ (x=0.1, 0.2; y=0.1, 0.2; z=0.2, 0.3, 0.4; denoted as PSCCF-81182, PSCCF-72173 and PSCCF-62264) were prepared by solid state reaction. The formation process, phase structure and microstructure of the prepared samples were measured using TG-DTA, FT/IR, XRD and SEM techniques. The mixed conductivity of the samples was measured using DC four-terminal method in the range of 150-950 °C. Chemical state of the elements was measured by XPS experiments. The results show that the prepared samples PSCCF-81182, PSCCF-72173 and PSCCF-62264 exhibit a single phase with cubic perovskite structure after sintered at 1200 °C for 6 h. The mixed conductivity of the samples increases with temperature up to a maximum value, and then decreases. At lower temperature, the conductivity follows small polaron hopping mechanism. The negative temperature dependence occurring at higher temperature is due to the creation of oxygen vacancies for charge balance. At intermediate temperature (600-800 °C), the mixed conductivity values of the prepared samples are all much higher than 100 S•cm-1，and can meet the demand of cathode materials for IT-SOFC. XPS tests show that Co and Fe elements in PSCCF-72173 are all of + 3 and + 4 valence. Absorbed oxygen can also be found from the XPS patterns, which is related to the concentration of oxygen vacancies in the perovskite-type oxides.

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Preparation of Ba1−La FeO3− (x = 0.1–0.6) with cubic perovskite phase and random distribution of oxide ion vacancy and their electrical conduction property and thermal expansion behavior

Solid State Ionics ◽

10.1016/j.ssi.2018.02.036 ◽

2018 ◽

Vol 320 ◽

pp. 76-83 ◽

Cited By ~ 8

Author(s):

Takashi Okiba ◽

Tsubasa Sato ◽

Fumito Fujishiro ◽

Eiki Niwa ◽

Takuya Hashimoto

Keyword(s):

Thermal Expansion ◽

Electrical Conduction ◽

Random Distribution ◽

Perovskite Phase ◽

Thermal Expansion Behavior ◽

Conduction Property ◽

Expansion Behavior ◽

Oxide Ion

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Thermal stability and thermal expansion behavior of FeCoCrNi2Al high entropy alloy

Advanced Powder Technology ◽

10.1016/j.apt.2020.12.019 ◽

2021 ◽

Author(s):

Mahesh S. Jadhav ◽

Disna Sahane ◽

Amit Verma ◽

Sheela Singh

Keyword(s):

Thermal Stability ◽

Thermal Expansion ◽

High Entropy Alloy ◽

Thermal Expansion Behavior ◽

High Entropy ◽

Expansion Behavior

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Anomalous thermal expansion behaviors of wood under dry and low-temperature conditions

Holzforschung ◽

10.1515/hf-2013-0103 ◽

2014 ◽

Vol 68 (5) ◽

pp. 567-574 ◽

Cited By ~ 3

Author(s):

Tsunehisa Miki ◽

Hiroyuki Sugimoto ◽

Yuzo Furuta ◽

Ichinori Shigematsu ◽

Kozo Kanayama

Keyword(s):

Thermal Expansion ◽

Linear Thermal Expansion ◽

Longitudinal Direction ◽

Mechanical Analysis ◽

Solid Wood ◽

Compression Pressure ◽

Thermal Expansion Behavior ◽

Expansion Behavior ◽

Dry Conditions ◽

Anomalous Thermal Expansion

Abstract The thermal expansion behavior of dry solid wood was investigated by dynamic dilatometry and thermal mechanical analysis. Anomalous thermal expansion behavior was observed concerning the displacement change under a constant compression pressure, which was not previously reported. Wood submitted to temperatures below 0°C under dry conditions exhibited a large increment in the linear thermal expansion coefficient (CLTE) and a sudden drop in the CLTE around 50°C as well as above 130°C during heating. In subsequent cooling/heating processes, these anomalous behaviors remained at temperatures below 100°C, although less pronounced, and disappeared at temperatures above 100°C. These behaviors were clearly perceptible in the radial and tangential directions but not in the longitudinal direction. The CLTE depended strongly on the heat and moisture history of the samples and the effects are species-specific.

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