Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

Park, Joong Sun; An, Jihwan; Lee, Min Hwan; Prinz, Friedrich; Lee, Won Young

doi:10.1016/j.jpowsour.2015.06.149

Cited by 28 publications

(11 citation statements)

References 41 publications

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“…The oxygen reduction process at the cathode remains the main limiting factor associated with solid oxide fuel cells, thus a detailed understanding of the reaction mechanism is necessary in order to improve the performance of these devices. The problem is of key importance for SOFCs, where apart from the ohmic drop, the slow kinetics of the electrode process is a source of significant energy loss [38,39]. In many studies concerning investigations of the kinetics of an oxygen reduction process, porous electrode materials were usually applied.…”

Section: Resultsmentioning

confidence: 99%

Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium

Dudek

Lis

Rapacz-Kmita

et al. 2016

Materials Science-Poland

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In this paper, the impact of partial substitution of calcium for barium in (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr on physicochemical properties of the powders and sintered samples was investigated. The powders, with various contents of calcium (x = 0, 0.02, 0.05, 0.1), were prepared by means of thermal decomposition of organometallic precursors containing EDTA. All of the BaCeO3-based powders synthesised at 1100 °C were monophasic with a rhombohedral structure, however, completely cubic BaZrO3-based solid solutions were obtained at 1200 °C. A study of the sinterability of BaZr0.9Y0.1O3 and BaCe0.9Y0.1O3-based pellets was performed under non-isothermal conditions within a temperature range of 25 to 1200 °C. The partial substitution of barium for calcium in the (Ba1-xCax) (M0.9Y0.1) O3, M = Ce, Zr solid solution improved the sinterability of the samples in comparison to the initial BaCe0.9Y0.1O3 or BaZr0.9Y0.1O3. The relative density of calcium-modified BaCe0.9Y0.1O3-based samples reached approximately 95 to 97 % after sintering at 1500 °C for 2 h in air. The same level of relative density was achieved after sintering calcium-modified BaZr0.9Y0.1O3 at 1600 °C for 2 h. Analysis of the electrical conductivity from both series of investigated materials showed that the highest ionic conductivity, in air and wet 5 % H2 in Ar, was attained for the compositions of x = 0.02 to 0.05 (Ba1-xCax)(M0.9Y0.1)O3, M = Zr, Ce. The oxygen reduction reaction on the interface Pt│BaM0.9Y0.1O3, M = Ce, Zr was investigated using Pt microelectrodes. Selected samples of (Ba1-xCax) (M0.9Y0.1)O3, M = Zr, Ce were tested as ceramic electrolytes in hydrogen-oxygen solid oxide fuel cells operating at temperatures of 700 to 850 °C.

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Section: Resultsmentioning

confidence: 99%

Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium

Dudek

Lis

Rapacz-Kmita

et al. 2016

Materials Science-Poland

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“…This phenomenon persisted even after annealing at 1200 • C. The lack of sensitivity of the metallic-sputtered sensors could be related to the yttria surface segregation. As stated by Park et al, the yttrium-rich surface obtained after annealing at high temperatures can result in a higher oxygen incorporation barrier and the reduction of the concentration of mobile oxide ion vacancies at the surface [32]. This could be crucial at low partial pressures, where few oxygen molecules reach the sensing electrode.…”

Section: Oxygen Sensorsmentioning

confidence: 96%

“…This was also confirmed by the AFM grain growth evolution shown in Figure 5. An increase in grain size could lead to fewer grain boundaries, where the ionic conductivity can be lower compared to the bulk [32]. the RF-oxide sensors displayed the shortest response time.…”

Section: Oxygen Sensorsmentioning

confidence: 99%

Influence of the Sputtering Technique and Thermal Annealing on YSZ Thin Films for Oxygen Sensing Applications

et al. 2021

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Yttria-stabilized zirconia (YSZ) thin films were deposited using direct current (reactive and metallic) and radio frequency magnetron sputtering. The effect of the deposition technique and annealing treatment on the microstructure and crystallinity of the thin films was assessed. Using the films produced in this work, oxygen gas sensors were built and their performance under vacuum conditions was evaluated. All the films exhibited a cubic crystalline structure after a post-deposition thermal treatment, regardless of the sputtering technique. When the annealing treatment surpassed 1000 °C, impurities were detected on the thin film surface. The oxygen gas sensors employing the reactive and oxide-sputtered YSZ thin films displayed a proportional increase in the sensor current as the oxygen partial pressure was increased in the evaluated pressure range (5 × 10−6 to 2 × 10−3 mbar). The sensors which employed the metallic-deposited YSZ films suffered from electronic conductivity at low partial pressures.

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“…[4][5][6][7][8] By using isotope exchange/depth profiling, Chao et al investigated the correlation between surface exchange kinetics and surface chemistry, showing that an additional layer at the electrolyte surface significantly enhanced the oxygen exchange kinetics without negatively impacting the oxygen transport. [10][11][12][13][14][15][16] Kim et al demonstrated that an approximately 120-nm-thick nanocrystalline gadolinia-doped ceria (GDC) interlayer deposited by pulsed laser deposition (PLD) technique provided active ORR sites, causing an approximately two-fold enhancement in peak power density, compared with the bare YSZ sample. Their results indicated that the optimal chemical composition at the electrolyte/cathode interfaces required for enhanced oxygen exchange was different from that required for fast transport through the bulk of the YSZ electrolyte.…”

Section: Introductionmentioning

confidence: 99%

“…Their results indicated that the optimal chemical composition at the electrolyte/cathode interfaces required for enhanced oxygen exchange was different from that required for fast transport through the bulk of the YSZ electrolyte . Recent observations revealed that surface exchange reactions occur more actively near the grain boundary (GB) region than the grain core . Kim et al .…”

Section: Introductionmentioning

confidence: 99%

Effects of Grain Boundaries at the Electrolyte/Cathode Interfaces on Oxygen Reduction Reaction Kinetics of Solid Oxide Fuel Cells

Choi

Koo

Ahn

2017

Bulletin Korean Chem Soc

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We systematically investigated the effects of grain boundaries (GBs) at the electrolyte/cathode interface of two conventional electrolyte materials, i.e., yttria-stabilized zirconia (YSZ) and gadolinia-doped ceria (GDC). We deposited additional layers by pulsed laser deposition to control the GB density on top of the polycrystalline substrates, obtaining significant improvements in peak power density (two-fold for YSZ and three-fold for GDC). The enhanced performance at high GB density in the additional layer could be ascribed to the accumulation of oxygen vacancies, which are known to be more active sites for oxygen reduction reactions (ORR) than grain cores. GDC exhibited a higher enhancement than YSZ, due to the easier formation, and thus higher concentration, of oxygen vacancies for ORR. The strong relation between the concentration of oxygen vacancies and the surface exchange characteristics substantiated the role of GBs at electrolyte/cathode interfaces on ORR kinetics, providing new design parameters for highly performing solid oxide fuel cells.

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Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

Cited by 28 publications

References 41 publications

Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium

Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium

Influence of the Sputtering Technique and Thermal Annealing on YSZ Thin Films for Oxygen Sensing Applications

Effects of Grain Boundaries at the Electrolyte/Cathode Interfaces on Oxygen Reduction Reaction Kinetics of Solid Oxide Fuel Cells

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Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

Cited by 28 publications

References 41 publications

Some observations on the synthesis and electrolytic properties of (Ba1-xCax) (M0.9Y0.1)O3, M = Ce, Zr-based samples modified with calcium

Some observations on the synthesis and electrolytic properties of (Ba1-xCax) (M0.9Y0.1)O3, M = Ce, Zr-based samples modified with calcium

Influence of the Sputtering Technique and Thermal Annealing on YSZ Thin Films for Oxygen Sensing Applications

Effects of Grain Boundaries at the Electrolyte/Cathode Interfaces on Oxygen Reduction Reaction Kinetics of Solid Oxide Fuel Cells

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Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium

Some observations on the synthesis and electrolytic properties of (Ba_1-xCa_x) (M_0.9Y_0.1)O₃, M = Ce, Zr-based samples modified with calcium