Challenges and prospects of anodes for solid oxide fuel cells (SOFCs)

Kan, Wang Hay; Thangadurai, Venkataraman

doi:10.1007/s11581-014-1334-6

Cited by 55 publications

(28 citation statements)

References 82 publications

(157 reference statements)

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“…Fuel electrodes of proton‐conducting SOCs, which are similar to the traditional oxygen‐conducting SOCs, should meet several requirements such as high electronic conductivity and sufficient ionic conductivity to ensure electro‐catalytic activity for fuel oxidation; chemical inert to the interactions with gas components of fuels (H 2 , CO, CO 2 , H 2 S) and other components of SOCs; thermal compatibility with cell components; structural and mechanical flexibility between oxidizing and reducing atmospheres (redox stability) …”

Section: Functional Materials Of Proton‐conducting Socsmentioning

confidence: 99%

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

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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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Section: Functional Materials Of Proton‐conducting Socsmentioning

confidence: 99%

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

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“…Microstructural degradation is also contributed to by agglomeration of nickel particles with time, which leads to the deterioration of both electrical conductivity and electrocatalytic activity . In addition, nickel is not suitable for the anodes of hydrocarbon‐fueled SOFCs: it catalyzes the cracking of hydrocarbons, resulting in carbon deposition and rapid blocking of anode, and it also suffers from sulfur poisoning (by hydrogen sulfide impurities in a fuel), which also causes the degradation of the electrochemical performance …”

Section: Introductionmentioning

confidence: 99%

“…[3][4][5] In addition, nickel is not suitable for the anodeso fh ydrocarbon-fueled SOFCs:i tc atalyzes the cracking of hydrocarbons, resulting in carbon deposition and rapid blocking of anode, and it also suffers from sulfur poisoning (by hydrogen sulfidei mpurities in af uel), which also causes the degradationoft he electrochemical performance. [4,6,7] Perovskite-type SrVO 3Àd and SrTiO 3 -based phases have been identified, among others,a spromising ceramic components for anodes of hydrocarbon-fueled SOFCs. [7][8][9] SrVO 3Àd is known to exhibit high metallic-like electronic conductivity under typical anode operation conditions:a pproximately 1000 Scm À1 at 800 8Ca nd p(O 2 )o fc irca 10 À20 bar.…”

Section: Introductionmentioning

confidence: 99%

Compromising Between Phase Stability and Electrical Performance: SrVO₃–SrTiO₃ Solid Solutions as Solid Oxide Fuel Cell Anode Components

et al. 2018

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The applicability of perovskite‐type SrVO3−δ in high‐temperature electrochemical energy conversion technology is hampered by the limited stability domain of the perovskite phase. The aim of the present work was to find a compromise between the phase stability and electrical performance by designing solid solutions in the SrVO3–SrTiO3 system. Increasing titanium content in SrV1−yTiyO3−δ (y=0–0.9) perovskites is demonstrated to result in a gradual shift of the upper‐p(O2) phase stability boundary toward oxidizing conditions: from ≈10−15 bar at 900 °C for undoped SrVO3−δ to ≈10−11–10−5 bar for y=0.3–0.5. Although the improvement in the phase stability is accompanied by a decrease in electrical conductivity, the conductivities of SrV0.7Ti0.3O3−δ and SrV0.5Ti0.5O3−δ at 900 °C remain as high as 80 and 20 S cm−1, respectively, and is essentially independent of p(O2) within the phase‐stability domain. Combined XRD, thermogravimetric analysis, and electrical studies revealed very sluggish kinetics of oxidation of SrV0.5Ti0.5O3−δ ceramics under inert gas conditions and a nearly reversible behavior after exposure to an inert atmosphere at elevated temperatures. Substitution by titanium in the SrV1−yTiyO3−δ system results also in a decrease of oxygen deficiency in perovskite lattice and a favorable suppression of thermochemical expansion. Variations of oxygen nonstoichiometry and electrical properties in the SrV1−yTiyO3−δ series are discussed in combination with the simulated defect chemistry of solid solutions.

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“…NiO + H2 → Ni + H2O [1] As elucidated in several reviews, Ni-YSZ cermet is the most used material as a SOFC fuel electrode [1][2][3][4]. However, it presents some drawbacks including those associated with thermal cycling, redox stability due to the significant volume changes upon oxidation of Ni to NiO and thus affecting the mechanical integrity of the cell, as well as sulphur deposition or coking when 3 carbon rich fuel streams are used [5,6].…”

Section: Introductionmentioning

confidence: 99%

The influence of the reducing conditions on the final microstructure and performance of nickel-yttria stabilized zirconia cermets

Monzón

Laguna‐Bercero

2016

Electrochimica Acta

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Ni-YSZ (yttria stabilized zirconia) cermets are the most widespread composite materials to be used as SOFC fuel electrodes. These materials are generally fabricated by the reduction of NiO to Ni in a NiO-YSZ composite, where the reducing conditions have a great effect in the final microstructure of the electrode. In the present work, several reducing conditions were explored in order to find the most suitable microstructure for anode-supported microtubular solid oxide fuel cells (SOFCs). Samples were firstly reduced in either pure or diluted H2 (dry or humidified), at temperatures ranging from 400 to 800 °C while their DC conductivity was monitored. The highest conductivity value was measured for the sample reduced in pure humidified hydrogen at 800°C. However, this sample experienced conductivity degradation in comparison with samples reduced under dry conditions. For the studied temperature range, nucleation of nano-porous nickel particles is firstly formed during reduction. However, from our experiments it was concluded that those nanoparticles are not stable with time, at least at temperatures between 600 ºC and 800 ºC. Electrochemical characterization of complete microtubular cells under real wet conditions was also performed under current load, confirming that the microstructure of the Ni-YSZ cermet is still evolving during operation.

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Challenges and prospects of anodes for solid oxide fuel cells (SOFCs)

Cited by 55 publications

References 82 publications

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

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

Compromising Between Phase Stability and Electrical Performance: SrVO₃–SrTiO₃ Solid Solutions as Solid Oxide Fuel Cell Anode Components

The influence of the reducing conditions on the final microstructure and performance of nickel-yttria stabilized zirconia cermets

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Challenges and prospects of anodes for solid oxide fuel cells (SOFCs)

Cited by 55 publications

References 82 publications

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

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

Compromising Between Phase Stability and Electrical Performance: SrVO3–SrTiO3 Solid Solutions as Solid Oxide Fuel Cell Anode Components

The influence of the reducing conditions on the final microstructure and performance of nickel-yttria stabilized zirconia cermets

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Compromising Between Phase Stability and Electrical Performance: SrVO₃–SrTiO₃ Solid Solutions as Solid Oxide Fuel Cell Anode Components