Stability of metal oxides against Li/Na carbonates in composite electrolytes

Loureiro, Francisco J.A.; Rajesh, S.; Figueiredo, Filipe M.; Marques, F.M.B.

doi:10.1039/c4ra11446a

Cited by 19 publications

(15 citation statements)

References 38 publications

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“…The total electrode impedance can only be estimated from fitting and extrapolation using the small spectra tail but follows the same trend in relative magnitude. Molten NLC migrates easily to the electrode compartment by capillary action and promotes the partial conversion of LC into La 2 O 2 (CO 3 ) (or related lithiated compounds), as shown in previous work . This reaction impacts the concentration of carbonate ions in the electrolyte and corresponding conductivity, besides dropping electrode performance.…”

Section: Resultsmentioning

confidence: 99%

“…Molten NLC migrates easily to the electrode compartment by capillary action and promotes the partial conversion of LC into La 2 O 2 (CO 3 ) (or related lithiated compounds), as shown in previous work. 5,6 This reaction impacts the concentration of carbonate ions in the electrolyte and corresponding conductivity, besides dropping electrode performance. The likely formation of resistive phases inside the molten carbonate flooded electrode pores and the decrease in active electrode area with inherent electrode degradation are both coherent with the observed large electrode impedances in directly deposited electrode layers (LC-thin and LC-thick), and with the relative magnitudes of the impedance of these two electrodes.…”

Section: Resultsmentioning

confidence: 99%

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Screening of electrode materials and cell concepts for composite ceria + salt electrolytes

Jamale

Marques

2018

Int J Energy Res

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Summary The optimization of the performance of electrodes (oxide‐based) for composite electrolytes (Ce0.9Gd0.1O1.95 + (Li0.52Na0.48)2CO3) is addressed in this work acting mostly on the electrode chemical nature (eg, LaCoO3, Li0.43NiO2, or LiNiO2), thickness (single and multiple screen‐printed layers), and cell layer concept (with/without barrier layers between electrode and electrolyte). The cell performance and stability were analyzed by electrochemical impedance spectroscopy, X‐ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. LaCoO3 electrodes deposited on the electrolyte using an intermediate barrier layer showed a promising area specific resistance of 0.22 Ω.cm2 at 600°C. This optimized cell processing route was adopted as reference to study the endurance performance of distinct electrode materials up to 100 hours in air, at 550°C, where lithiated NiO showed the best stability.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Screening of electrode materials and cell concepts for composite ceria + salt electrolytes

Jamale

Marques

2018

Int J Energy Res

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“…The green pellets were sintered at 690°C for 1 h. Detailed processing conditions were described elsewhere [28][29][30][31]. Composite powders were prepared by high energy milling, carried out in a planetary ball mill with Nylon containers and zirconia-based balls (balls to powder mass ratio of 10:1, respectively).…”

Section: Methodsmentioning

confidence: 99%

“…Following our own experience with these materials [28][29][30][31], Gd-doped ceria (CGO) was selected as oxide phase, while eutectic mixture of sodium and lithium carbonates (NLC) was used as second phase. Following our own experience with these materials [28][29][30][31], Gd-doped ceria (CGO) was selected as oxide phase, while eutectic mixture of sodium and lithium carbonates (NLC) was used as second phase.…”

Section: Introductionmentioning

confidence: 99%

“…To illustrate the potential of this approach, a few membrane compositions were selected with high-oxide phase content (70-90 vol%). Following our own experience with these materials [28][29][30][31], Gd-doped ceria (CGO) was selected as oxide phase, while eutectic mixture of sodium and lithium carbonates (NLC) was used as second phase. With this option, published data on the composite single-phase constituents are readily available, and a model membrane performance can be easily defined.…”

Section: Introductionmentioning

confidence: 99%

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Benchmarking the ambipolar conductivity of composite electrolytes for gas separation membranes

Patrício

Marques

2016

Int. J. Energy Res.

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Summary Composite electrolytes including an oxide (Gd‐doped ceria, 70, 80, and 90 vol%) and a eutectic mixture of alkaline carbonates (Na2CO3 and Li2CO3) were produced by joint milling and firing of all constituents. The microstructure of these composites was studied by scanning electron microscopy/energy‐dispersive X‐ray spectroscopy, and they were further studied by impedance spectroscopy in air. Analysis of impedance data at low and high temperature was used to separate the electrical performance of each constituent phase, providing valuable information on the membrane electrical microstructure. Furthermore, a new tool is introduced for the assessment of the electrical microstructure efficiency of composite membranes, as a diagram relating the partial ionic transport numbers of main charge carriers and the membrane ambipolar conductivity. Using this type of diagram, the electrical features of actual composite membranes were mapped against an ideal membrane performance where microstructural effects are absent. The potential of this procedure to benchmark and discriminate the electrical characteristics of distinct membranes is demonstrated in this manner. Copyright © 2016 John Wiley & Sons, Ltd.

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Assessment of processing route on the performance of ceria‐based composites

et al. 2021

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Gd-doped ceria (GDC)-based composites, including a eutectic mixture of lithium and sodium carbonate (NLC) as second phase, were prepared using several processing routes, namely chemical synthesis, co-firing of both phases, or impregnation of a presintered porous matrix. LiAlO 2 -based composites were also prepared and used as reference. The structural, microstructural, and electrical properties (impedance spectroscopy in air, up to 700 C) of these materials were assessed in detail. A limited set of compositions was also used in measurements of total electrical conductivity at different oxygen partial pressures (from 0.21 to <10 −25 atm), in the 600 C to 700 C range. The results obtained confirmed the enormous impact of the processing route on the percolation of the ceramic phase. In the exploited range of operating conditions, GDC-NLC composites prepared by infiltration of molten carbonates within a mechanically robust ceramic matrix exhibit a high total ionic conductivity strongly influenced by the contribution of the molten salt while the ceramic phase is decisive in the appearance of a significant component of electronic conductivity under reducing conditions.

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Stability of metal oxides against Li/Na carbonates in composite electrolytes

Cited by 19 publications

References 38 publications

Screening of electrode materials and cell concepts for composite ceria + salt electrolytes

Screening of electrode materials and cell concepts for composite ceria + salt electrolytes

Benchmarking the ambipolar conductivity of composite electrolytes for gas separation membranes

Assessment of processing route on the performance of ceria‐based composites

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