Reactivation of chromia poisoned oxygen exchange kinetics in mixed conducting solid oxide fuel cell electrodes by serial infiltration of lithia

Seo, Han Gil; Staerz, Anna; Kim, Dennis; Klotz, Dino; Nicollet, Clément; Xu, Michael; LeBeau, James M.; Tuller, Harry L.

doi:10.1039/d1ee03975j

Cited by 15 publications

(27 citation statements)

References 71 publications

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“…78,79 A common property of all these oxides is their acidity relative to usual SOFC cathode material surfaces. 27,[80][81][82] While this fact has already been recognized previously, 27,81 no conclusive mechanistic explanation for the correlation of surface acidity and oxygen exchange kinetics has been brought forward yet. While a detailed experimental and theoretical investigation of different combinations of surface oxides and host materials is far beyond the scope of this study, we suspect that the mechanism behind the here investigated sulphate induced degradation plays a major role in this discussion.…”

Section: Effects Of Different Acidic Adsorbatesmentioning

confidence: 98%

Electronic and ionic effects of sulphur and other acidic adsorbates on the surface of an SOFC cathode material

et al. 2023

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Section: Effects Of Different Acidic Adsorbatesmentioning

confidence: 98%

Electronic and ionic effects of sulphur and other acidic adsorbates on the surface of an SOFC cathode material

et al. 2023

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“…This insures that the contribution of gas phase diffusion and bulk oxygen ion diffusion to the overall kinetics are negligible, as vigorously examined and confirmed in our preceding studies. [23,28] As a consequence, the overall redox kinetics are solely limited by the oxygen surface exchange reaction. The pristine specimen was first measured and then infiltrated with the Si-species at a dilute concentration of 0.02 at% with respect to PCO and re-measured.…”

Section: Poisoning and Recovery Of The Oxygen Exchange Kineticsmentioning

confidence: 99%

“…where k B is the Boltzmann constant, T the temperature in Kelvin, and c O the total concentration of lattice oxygen (5.035 10 22 cm -3 ). [33] As k el is derived from experiments that rely on the response to changes in electrical potential (impedance spectroscopy), while k chem is determined from experiments that rely on the response to changes in chemical potential (pO 2 step in conductivity relaxation), to properly compare them one must take into consideration the thermodynamic factor (w e ) [23,42] and surface area (S A ) as in the following relation: [28] k S k w k T e R c w…”

Section: Evaluation Of Electrochemical Performancementioning

confidence: 99%

Tuning Surface Acidity of Mixed Conducting Electrodes: Recovery of Si‐Induced Degradation of Oxygen Exchange Rate and Area Specific Resistance

et al. 2022

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metal oxide-based gas sensors, for which device performance relies on rapid oxygen exchange reactions at the gas-solid interfaces. [1][2][3][4][5][6][7] In SOFCs, the oxygen reduction reaction (ORR) occurs at the cathode and the corresponding polarization resistance depends on the adsorption/dissociation of oxygen species on the surface, followed by charge transfer between the surface and the adsorbed species, and finally the incorporation of charged oxygen ionic species into the electrode lattice. Although many studies related to improving the initial performance of mixed conducting metal oxides have been pursued to date, particularly focused on tuning the oxygen exchange coefficient (k chem ), the performance of such devices often degrades rapidly due to the inevitable poisoning by extrinsic sources over time during device operation. [8][9][10][11] Sources of Si-impurities are not only widely present in material processing and testing (e.g., the use of quartz reactors, furnace refractories, glass or glass-ceramic sealants, and thermal insulation materials), but also during device operation (e.g., volatile organic silicon compounds (VOSCs) and gas impurities). [11][12][13][14][15][16][17][18][19][20][21][22] Si-contamination is known to cause significant performance degradation of many electrochemical devices. [8] For example, Perz et al. showed that silica reacts with the La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ (LSCF) surface, a mixed ionic and electronic conducting (MIEC) cathode commonly applied in SOFCs, forming a continuous La-Sr-silicate layer. [22] This impurity layer limits adsorption/dissociation of oxygen molecules on the LSCF surface, increasing the area-specific resistance (ASR) by a factor 6 after long-term operation (1340 h) at 700 °C. Zhao et al. reported the formation of a blocking siliceous layer on dense thin films of Pr 0.1 Ce 0.9 O 2-δ (PCO), originating from quartz tubes or furnace insulation utilized during measurement, leading to the degradation of the oxygen surface exchange coefficient (k chem ) by a factor 40. [19] Hertz et al. demonstrated the ability to reduce the ASR associated with thin film interdigitated Pt electrodes on a yttria-stabilized zirconia (YSZ) electrolyte by 1000-fold following HF etching of surface silica species, thereby allowing oxygen gas to readily access the triple phase reaction sites. [15] To date, most previous studies point to silica forming a continuous glassy blocking layer as the source of the degradation.Metal oxides are an important class of functional materials, and for many applications, ranging from solid oxide fuel/electrolysis cells, oxygen permeation membranes, and oxygen storage materials to gas sensors (semiconducting and electrolytic) and catalysts, the interaction between the surface and oxygen in the gas phase is central. Ubiquitous Si-impurities are known to impede this interaction, commonly attributed to the formation of glassy blocking layers on the surface. Here, the surface oxygen exchange coefficient (k chem ) is examined for Pr 0.1 Ce 0.9 O 2...

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“…Ji et al suggested that gas diffusion in porous CeO 2Àd does not have an effect on the surface exchange kinetics when the temperature is below 1100 1C, 24 while Seo et al found that gas diffusion can be ignored for porous Pr 0.1 Ce 0.9 O 2Àd below 600 1C. 36 The inhomogeneous surface exchange rate at different gassolid interfaces is another intractability and inevitable problem, which is mainly caused by the inhomogeneity of p O 2 and particle size for a porous material. The inhomogeneity in oxygen partial pressure, which originates from gas diffusion in pores, is determined by the porosity (e), pore radius (r, cm), and gas diffusion depth (L d , cm).…”

Section: Possible Physical Process For Orr In Porous Miec Electrodementioning

confidence: 99%

“…), Ruddlesden-Popper oxides (La 2À2x Sr 2x Ni 1Àx MnO 4+d , 45 Nd 2 NiO 4+d , 46 La 2 NiO 4+d 47), and fluorite solid solutions (PCO). 36…”

mentioning

confidence: 99%

Perspective on high-temperature surface oxygen exchange in a porous mixed ionic-electronic conductor for solid oxide cells

Han

Jiang

Zhang

et al. 2023

Phys. Chem. Chem. Phys.

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Reactivation of chromia poisoned oxygen exchange kinetics in mixed conducting solid oxide fuel cell electrodes by serial infiltration of lithia

Abstract: Solid oxide fuel cells have the potential to render the conversion from fuel to electrical energy more efficienct while lowering emissions. The technology, however, suffers from performance degradation due to...

Cited by 15 publications

References 71 publications

Electronic and ionic effects of sulphur and other acidic adsorbates on the surface of an SOFC cathode material

Electronic and ionic effects of sulphur and other acidic adsorbates on the surface of an SOFC cathode material

Tuning Surface Acidity of Mixed Conducting Electrodes: Recovery of Si‐Induced Degradation of Oxygen Exchange Rate and Area Specific Resistance

Perspective on high-temperature surface oxygen exchange in a porous mixed ionic-electronic conductor for solid oxide cells

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