Investigation of electrical conductivity and seebeck coefficient of Ca-and Sr-doped LaCrO<sub>3</sub>

Stakkestad, G.; Faaland, Sonia; Sigvartsen, T.

doi:10.1080/01411599608242400

Cited by 5 publications

(4 citation statements)

References 7 publications

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“…Among these strategies, the chemical modification of LaCrO 3 by introducing Sr 2+ and Ca 2+ has been reported to be effective to improve the sintering properties and to increase its electrical conductivity 2,24,25 . Unmodified LaCrO 3 shows p‐type conduction due to the holes in the 3d band of the chromium ions.…”

Section: Introductionmentioning

confidence: 99%

“…[21][22][23] Among these strategies, the chemical modification of LaCrO 3 by introducing Sr 2+ and Ca 2+ has been reported to be effective to improve the sintering properties and to increase its electrical conductivity. 2,24,25 Unmodified LaCrO 3 shows p-type conduction due to the holes in the 3d band of the chromium ions. Substitution of divalent metal ions, such as Sr 2+ or Ca 2+ , for lanthanum, leads to a charge-compensating transition of Cr 3+ to Cr 4+ under oxidizing conditions.…”

Section: Introductionmentioning

confidence: 99%

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Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders

Liu

Zhai

et al. 2023

J Am Ceram Soc.

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Preparation condition plays a critical role in the structure and properties of ceramics. However, exactly how it affects lanthanum chromate (LaCrO3)‐based conducting oxides remains poorly understood. In this work, the effects of sintering temperature on the crystal structure, microstructure, and electrical conductivity of pure and Sr2+‐/Ca2+‐substituted LaCrO3 ceramics have been investigated. It is found that the calcining temperature can be reduced by 200–300 K to obtain a single‐perovskite structure by using nano‐powders as raw materials. A sintering temperature–induced structural transition from orthorhombic Pbnm phase to rhombohedral Rtrue3¯c$R\bar 3c$ phase is found in La0.8Sr0.2CrO3, and the possible mechanism is attributed to a thermally induced transformation of the thermodynamic metastable orthorhombic to stable rhombohedral phase after thermal treatment at higher temperatures. The electrical conductivity in a broad temperature range (from room temperature up to 1923 K) is measured. The conductivity increases with the elevated sintering temperature and soaking time, and it shows a remarkable enhancement by introducing the Sr and Ca ions. These results suggest that the sintering temperature should be well controlled and optimized to obtain desired crystal structure and electrical conductivity in LaCrO3‐based materials for various applications.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders

Liu

Zhai

et al. 2023

J Am Ceram Soc.

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“…In our previous publications [7,8] we reported on the electrical conductivity, microstructure, and mechanical properties of Ca-and Sr-doped LaCrO 3 interconnects for SOFO. Relative density, secondary phases, and grain boundary layers were found to have an impact on the electrical conductivity and the mechanical strength of these materials.…”

Section: Introductionmentioning

confidence: 99%

“…Doping with aliovalent B-site additives reduces the lattice expansion signi®cantly [6]. The lanthanum chromite powders that we have chosen to characterize contain the traditional Ca and Sr acceptor dopants, Ni and Zn dopants, and some double dopants (Sr with Ni, Cu, and Mg).In our previous publications [7,8] we reported on the electrical conductivity, microstructure, and mechanical properties of Ca-and Sr-doped LaCrO 3 interconnects for SOFO. Relative density, secondary phases, and grain boundary layers were found to have an impact on the electrical conductivity and the mechanical strength of these materials.…”

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confidence: 99%

Surface chemistry of lanthanum chromite I. Multivariate data modelling of Brunauer-Emmett-Teller surface area by the use of particle size distribution data from photon-correlation spectroscopy measurements

Stakkestad

Sjöblom

Grung

et al. 1999

Colloid & Polymer Science

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IntroductionThe interconnect is a critical component in a planar solid oxide fuel cell (SOFC) since, in addition to acting as the electrical connection between individual cells in series, it must also be gas tight in order to prevent mixing of the fuel and oxidizer. Doped lanthanum chromites exhibit the required phase stability, high electronic conductivity, and low ionic conductivity in both reducing and oxidizing environments making them suitable as interconnects at high temperatures (1000°C). Additionally, these materials are chemically compatible with the other fuel cell components [1]. Some independent studies reveal, however, that lanthanum chromite expands in a reducing atmosphere [2±5], at oxygen partial pressures well within the eective operating range of an SOFC. Doping with aliovalent B-site additives reduces the lattice expansion signi®cantly [6]. The lanthanum chromite powders that we have chosen to characterize contain the traditional Ca and Sr acceptor dopants, Ni and Zn dopants, and some double dopants (Sr with Ni, Cu, and Mg).In our previous publications [7,8] we reported on the electrical conductivity, microstructure, and mechanical properties of Ca-and Sr-doped LaCrO 3 interconnects for SOFO. Relative density, secondary phases, and grain boundary layers were found to have an impact on the electrical conductivity and the mechanical strength of these materials.Production of gas-tight, defect-free interconnects for SOFC is important regarding electrical output and lifetime. Defect-free ceramic composites with ®ne grain microstructures can be obtained by the processing of colloidal particles [9]. During the mixing, dispersing, forming, and ®ring steps good colloidal control and hence knowledge of the surface chemistry of the components is important. Sintering of the green body to maximum density depends on the surface free energy available in the powder, and the particle packing eciency.Hence, important characterization of the ceramic powders is by the Brunauer-Emmett-Teller (BET) surface area, and by the particle size distribution. Knowledge about the surface properties also gives guidelines Abstract Particle size distributions, measured by photon-correlation spectroscopy and Brunauer-EmmettTeller (BET) surface areas, were determined for several lanthanum chromite powders with dierent dopants. Principal component analysis (PCA) was used to reveal similarities among the dierent powders with regard to the input variables particle size, BET surface area, and calcination temperature. Correlation among the variables was also easily revealed by PCA. Partial-least-squares multivariate-response modelling was used to calibrate the BET surface area from particle size data and calcination temperatures. A model explaining 93% of the variance in the data, with good predictive power, was developed. The model revealed that the content of smallest-sized particles and the calcination temperature were important parameters in the prediction of the BET surface area.

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Exploring the impact of multivalent substitution on high-temperature electrical conductivity in doped lanthanum chromite perovskites: An experimental and ab-initio study

Mena,

Mendoza-Estrada,

Sabolsky

et al. 2024

Journal of the European Ceramic Society

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Investigation of electrical conductivity and seebeck coefficient of Ca-and Sr-doped LaCrO₃

Cited by 5 publications

References 7 publications

Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders

Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders

Surface chemistry of lanthanum chromite I. Multivariate data modelling of Brunauer-Emmett-Teller surface area by the use of particle size distribution data from photon-correlation spectroscopy measurements

Exploring the impact of multivalent substitution on high-temperature electrical conductivity in doped lanthanum chromite perovskites: An experimental and ab-initio study

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Investigation of electrical conductivity and seebeck coefficient of Ca-and Sr-doped LaCrO3

Cited by 5 publications

References 7 publications

Sintering temperature–induced structural transition in LaCrO3‐based conducting oxides synthesized from nano‐powders

Sintering temperature–induced structural transition in LaCrO3‐based conducting oxides synthesized from nano‐powders

Surface chemistry of lanthanum chromite I. Multivariate data modelling of Brunauer-Emmett-Teller surface area by the use of particle size distribution data from photon-correlation spectroscopy measurements

Exploring the impact of multivalent substitution on high-temperature electrical conductivity in doped lanthanum chromite perovskites: An experimental and ab-initio study

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Investigation of electrical conductivity and seebeck coefficient of Ca-and Sr-doped LaCrO₃

Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders

Sintering temperature–induced structural transition in LaCrO₃‐based conducting oxides synthesized from nano‐powders