Silica: ubiquitous poison of metal oxide interfaces

Staerz, Anna; Seo, Han Gil; Defferriere, Thomas; Tuller, Harry L.

doi:10.1039/d1ta08469k

Cited by 14 publications

(16 citation statements)

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“…Through a systematic study of different additives, it was found that oxides described by Smith as basic, for example, lithia or calcia, resulted in an increased response rate, while those considered acidic, for example, silica or alumina, suppressed the response speed 18 . In line with the findings of Nicollet et al., the relaxation kinetics of PCO onto which Si‐species had been added to the surface responded considerably slower to stepwise oxygen changes than the pristine material, Figure 4B (blue) 3,18,27,43,44 . On the other hand, the basic additive lithia, resulted in an increased response rate, see Figure 4B (yellow).…”

Section: Case Studiessupporting

confidence: 75%

“…For example, Si‐species are recognized as an ubiquitous poison in metal oxide processing steps, for example, originating from furnace refractories and sealants/greases 3,27 . The widespread use of volatile organic silicon compounds (VSCs) in consumer products, for example, in electronics, furniture, healthcare, pharmaceuticals, cosmetics, and cookware, is already known to degrade SMOX‐based sensors 8,22,27 ; and therefore there is a significant push in the industry to develop stable sensor options 3,8 . Si‐species are known to significantly degrade SOFC cathode materials as well.…”

Section: Proposed Mechanisms For Surface Additive Influence On Intera...mentioning

confidence: 99%

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Surface electron modulation of metal oxide‐based electrochemical devices by surface additives—linking sensors and fuel cells

Staerz,

Seo,

Tuller

2023

J Am Ceram Soc.

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The interaction between ambient oxygen and the metal oxide surface is central to various electrochemical devices. Solid oxide fuel cell cathodes and semiconducting metal oxide gas sensors are two prominent examples. Parallels between these two systems are highlighted in this perspective. In both cases, the presence of foreign surface species has been found to significantly alter the interactions of the metal oxides’ surfaces with oxygen. On the one hand, interactions are hindered due to the presence of certain impurities, such as the degradation of fuel cell cathode by Si‐species that originate from processing or from operating environments. On the other hand, electrochemically active noble metal additives have been intentionally used to tune the sensor response of metal oxides. In the case of electrochemically active additives, the need for operando spectroscopies to elucidate the mechanism is discussed. Electronic coupling of the surface additive with the metal oxide is found to play a central role in both cases. We use these results to demonstrate that insights gained from either field can be effectively applied to the other.

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Section: Case Studiessupporting

confidence: 75%

Section: Proposed Mechanisms For Surface Additive Influence On Intera...mentioning

confidence: 99%

Surface electron modulation of metal oxide‐based electrochemical devices by surface additives—linking sensors and fuel cells

Staerz,

Seo,

Tuller

2023

J Am Ceram Soc.

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“…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. [ 8–11 ]…”

Section: Introductionmentioning

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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“…12,34,35 Electrolyte poisons reduce the ion transport capacity of the electrolyte to shut down the battery and prevent heat accumulation. 36,37 Thermal polymerization and thermal dedoping both involve chemical changes. Thermal polymerization inhibits ion transport within the electrolyte at high temperatures by self-polymerization to shut down the battery.…”

Section: Introductionmentioning

confidence: 99%

Thermally responsive polymers for overcoming thermal runaway in high-safety electrochemical storage devices

Chen

Liu

Feng

et al. 2023

Mater. Chem. Front.

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Silica: ubiquitous poison of metal oxide interfaces

Abstract: In this review, we consider electrochemical applications, broadly conceived, in which both ions and electrons play key roles in device operation and where exchange of oxygen between the gas and...

Cited by 14 publications

References 138 publications

Surface electron modulation of metal oxide‐based electrochemical devices by surface additives—linking sensors and fuel cells

Surface electron modulation of metal oxide‐based electrochemical devices by surface additives—linking sensors and fuel cells

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

Thermally responsive polymers for overcoming thermal runaway in high-safety electrochemical storage devices

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