Influence of dopant levels on the hydration properties of SZCY and BZCY proton conducting ceramics for hydrogen production

Leonard, Kwati; Lee, Young Sung; Okuyama, Yuji; Miyazaki, Kuninori; Matsumoto, Hiroshige

doi:10.1016/j.ijhydene.2016.10.120

Cited by 49 publications

(41 citation statements)

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“…For LCZ, the correct phase was not obtained by solid state reaction in the range 1100 to 1400 °C, so it was prepared by sol-gel synthesis instead. XRD confirms that the intended phase was obtained for each of the fresh powders after synthesis, as the peak patterns are consistent with previous literature, see Figure 3 [37,43,50,[57][58][59].The SZCY powder also contains minor CeO 2 and SrY 2 O 4 impurity phases. The peak splitting for BCN is consistent with previous work, where it was suggested that hydrated and dehydrated phases coexist at 1200 °C and heating to 1300 °C and above completely dehydrates the material resulting in single peaks [43].…”

Section: 1compatibility With Sintering In Reducing Atmospheresupporting

confidence: 89%

“…Only a thin portion of the hydrogen electrode layer, as required for electrochemical function, is retained in the MSC design. Figure 2 shows the conductivities of representative proton conductors [11,[35][36][37][38][39][40][41][42][43]. While BZCYtype materials are the most-studied proton conductors for PCFCs due to their high conductivity, other proton conductors may be more compatible with the metal-supported cell architecture, materials set, and processing constraints.…”

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confidence: 99%

“…Finally, thin layers of proton conductors supported on porous steel supports are prepared and electrochemically tested. BZCYYb1711 [11] 700 600 500 400 LSP [42] LCT [41] LCN [39] LCO [40] LCZ [38] BCN [43] SZCY [37] BZY [36] Conductivity Aldrich, ≥99%) in deionized water. Citric acid/metal molar ratio was 1:1.…”

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confidence: 99%

“…Conductivities of representative proton conductors. Data are reproduced from[11,[35][36][37][38][39][40][41][42][43].…”

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confidence: 99%

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Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells

2019

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Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells Permalink https://escholarship.org/uc/item/7fr6v5mf Journal Solid State Ionics, 332(Chem. Soc. Rev. 39 2010) Abstract Proton conducting oxide electrolyte materials could potentially lower the operating temperature of metal-supported solid oxide cells (MS-SOCs) to the intermediate range 400 to 600 °C. The porous metal substrate provides the advantages of MS-SOCs such as high thermal and redox cycling tolerance, low-cost of structural materials, and mechanical ruggedness. In this work, viability of co-sintering fabrication of metal-supported proton conducting solid oxide cells is investigated. Candidate proton conducting oxides including perovskite oxides BaZr 0.7 Ce 0.2 Y 0.1 O 3-δ , SrZr 0.5 Ce 0.4 Y 0.1 O 3-δ , and Ba 3 Ca 1.18 Nb 1.82 O 9-δ , pyrochlore oxides La 1.95 Ca 0.05 Zr 2 O 7-δ and La 2 Ce 2 O 7 , and acceptor doped rare-earth ortho-niobate La 0.99 Ca 0.01 NbO 4 are synthesized via solid state reactive or sol-gel methods. These ceramics are sintered at 1450 °C in reducing environment alone and supported on Fe-Cr alloy metal support, and their key characteristics such as phase formation, sintering property, and chemical compatibility with metal support are determined. Most electrolyte candidates suffer from one or more challenges identified for this fabrication approach, including: phase decomposition in reducing atmosphere, evaporation of electrolyte constituents, contamination of the electrolyte with Si and Cr from the metal support, and incomplete electrolyte sintering. In contrast, La 0.99 Ca 0.01 NbO 4 is found to be highly compatible with the metal support and co-sintering processing in reducing atmosphere. A metal-supported cell is fabricated with La 0.99 Ca 0.01 NbO 4 electrolyte, ferritic stainless steel support, Pt air electrode and nanoparticulate ceria-Ni hydrogen electrocatalyst. The total resistance is 50 Ω•cm 2 at 600 °C. This work clearly demonstrates the challenges, opportunities, and breakthrough of metal-supported proton-conducting solid oxide cells by co-sintering fabrication.

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Section: 1compatibility With Sintering In Reducing Atmospheresupporting

confidence: 89%

mentioning

confidence: 99%

mentioning

confidence: 99%

“…Conductivities of representative proton conductors. Data are reproduced from[11,[35][36][37][38][39][40][41][42][43].…”

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confidence: 99%

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Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells

2019

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“…However, its sufficient O 2− conductivity, ~0.1 S cm −1 , only takes place under high temperature (~1000 °C) [2,3], leading to high system costs and complexity, severe drawback on material durability, slow start-up rate, thus impeding the SOFCs commercial process. Therefore, the LTSOFC research and development have become worldwide, but to maintain the high efficiency and to design high ionic conductive electrolyte materials functioned at low temperatures, have been a critical challenge [4,5,6,7,8]. …”

Section: Introductionmentioning

confidence: 99%

Semiconductor-Ionic Nanocomposite La0.1Sr0.9MnO3−δ-Ce0.8Sm0.2O2−δ Functional Layer for High Performance Low Temperature SOFC

Wang

et al. 2018

Materials

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A novel composite was synthesized by mixing La0.1Sr0.9MnO3−δ (LSM) with Ce0.8Sm0.2O2−δ (SDC) for the functional layer of low temperature solid oxide fuel cell (LT-SOFC). Though LSM, a highly electronic conducting semiconductor, was used in the functional layer, the fuel cell device could reach OCVs higher than 1.0 V without short-circuit problem. A typical diode or rectification effect was observed when an external electric force was supplied on the device under fuel cell atmosphere, which indicated the existence of a junction that prevented the device from short-circuit problem. The optimum ratio of LSM:SDC = 1:2 was found for the LT-SOFC to reach the highest power density of 742 mW·cm−2 under 550 °C The electrochemical impedance spectroscopy data highlighted that introducing LSM into SDC electrolyte layer not only decreased charge-transfer resistances from 0.66 Ω·cm2 for SDC to 0.47–0.49 Ω·cm2 for LSM-SDC composite, but also decreased the activation energy of ionic conduction from 0.55 to 0.20 eV.

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Gas Humidification Impact on the Properties and Performance of Perovskite‐Type Functional Materials in Proton‐Conducting Solid Oxide Cells

Wang

Medvedev

Shao

2018

Adv Funct Materials

103

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Fuel cells and electrolysis cells as important types of energy conversiondevices can be divided into groups based on the electrolyte material. However, solid oxide cells (SOCs) based on conventional oxygen-ion conductors are limited by several issues, such as high operating temperature, the difficulty of hydrogen purification from water, and inferior stability. To avoid these problems, proton-conducting oxides are proposed as electrolytes for SOCs in electrolysis and fuel cell modes. Since water vapor partial pressure (pH 2 O) is one of the main parameters determining the proton concentration in proton-conducting oxides (characteristics of which can be either improved or deteriorated), the pH 2 O control is extremely important for the optimization of the devices' performance and stability. This review provides an overview of the research progresses made for proton-conducting SOCs, especially for the impact of gas humidification on the operability and performance. Fundamental understanding of the main processes in proton-conducting SOCs and design principles for the key components are summarized and discussed. The trends, challenges, and future directions that exist in this dynamic field are also pointed out. This review will inspire interest from various disciplines and provide some useful guidelines for future development of proton-conductor-based energy storage and conversion systems.

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Influence of dopant levels on the hydration properties of SZCY and BZCY proton conducting ceramics for hydrogen production

Cited by 49 publications

References 48 publications

Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells

Assessment of co-sintering as a fabrication approach for metal-supported proton-conducting solid oxide cells

Semiconductor-Ionic Nanocomposite La0.1Sr0.9MnO3−δ-Ce0.8Sm0.2O2−δ Functional Layer for High Performance Low Temperature SOFC

Gas Humidification Impact on the Properties and Performance of Perovskite‐Type Functional Materials in Proton‐Conducting Solid Oxide Cells

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