Performance improvement by metal deposition at the cathode active site in solid oxide fuel cells

Shin, Seong‐Ho; Yoon, Byoung Young; Kim, Jung Hyun; Bae, Joong Myeon

doi:10.1016/j.ijhydene.2013.04.115

Cited by 11 publications

(7 citation statements)

References 22 publications

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“…However, upon electrochemical operation under current load, oxygen partial pressure is sharply reduced locally at TPBs. PtO 2 is thus subsequently reduced to metallic Pt and reassembled preferentially at the electrochemically reactive sites of TPBs, where the oxygen partial pressure is the lowest on the cathode internal surface . In the cell with unary Pt ALD coating, the Pt redeposition is merely taking place at the TPBs, and both the YSZ and the LSM surfaces are free of Pt nanograins. , However, once the dual catalysts Pt and Co are applied using ALD, much smaller Pt particles of ∼10 nm in thickness uniformly and densely distributed on all YSZ grain surface in cell no.…”

Section: Resultsmentioning

confidence: 99%

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

et al. 2019

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The sluggish oxygen reduction reaction (ORR) in the cathode is hindering the power density of solid oxide fuel cells (SOFCs). Infiltration of catalyst into the cathode of SOFCs is promising to accelerate the ORR. However, the degradation associated with the coarsening of the nanocatalyst is intense. To stabilize the catalyst, atomic layer deposition (ALD) is employed to coat a dual electrocatalyst consisting of a superjacent 2 nm CoO x layer and superjacent 3 nm discrete Pt particles into the porous lanthanum strontium manganite (LSM)/yttria-stabilized zirconia (YSZ) cathode. After 504 h of operation at 750 °C, the ALD coating resulted in the peak power density enhancement by ∼200%, while CoO x becomes Mnenriched (MnCo)O x nanograins coupling with nano-Pt. The Pt/(MnCo)O x nanocouplings are uniformly distributed on the YSZ grain surface, triple-phase boundaries, and at LSM/LSM surface grain boundaries. This study demonstrates an effective approach of stabilizing the minute amount of catalyst for enhancing ORR activity at elevated temperatures.

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Section: Resultsmentioning

confidence: 99%

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

et al. 2019

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“…It is reported in the literature that Pt readily diffuses into the cathodes under cathodic polarization conditions, and the location of Pt deposition is dependent on the cathode materials. − Bae et al reported that Pt is deposited at the electrode/electrolyte interface of the LSM cathode, while Pt is deposited on the surface of LSCF particles throughout the cathode . The migration of gaseous Pt species such as PtO 2 is likely driven by the difference in oxygen partial pressure between the current collector and active reaction sites of the cathodes during polarization, and the deposition of Pt at the active reaction sites indicates that the gaseous PtO 2 tends to be reduced under the electrochemical reduction conditions .…”

Section: Resultsmentioning

confidence: 99%

“…51 The migration of gaseous Pt species such as PtO 2 is likely driven by the difference in oxygen partial pressure between the current collector and active reaction sites of the cathodes during polarization, and the deposition of Pt at the active reaction sites indicates that the gaseous PtO 2 tends to be reduced under the electrochemical reduction conditions. 51 In the case of the LNO cathode, the deposition of Pt is more complex, as shown in Figure 6. As LNO is a mixed-ionic/ electronic conductor, the whole surface of LNO particles is active for the ORR, and therefore, Pt is initially deposited onto the surface of LNO particles under cathodic polarization conditions.…”

Section: Electrochemical Properties Of the Lno Cathode Undermentioning

confidence: 99%

Electrochemically Assisted Construction of a La₂NiO_4+δ@Pt Core–Shell Structure for Enhancing the Performance and Durability of La₂NiO_4+δ Cathodes

Zou,

Yue,

et al. 2023

ACS Appl. Mater. Interfaces

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Ruddlesden–Popper oxide La2NiO4+δ (LNO) has a high ionic conductivity and good thermal match with the electrolyte of solid oxide fuel cells (SOFCs); however, LNO suffers from performance decay owing to the La surface segregation under the operation conditions of SOFCs. Herein, we report an in situ electrochemical decoration strategy to improve the electrocatalytic activity and durability of LNO cathodes. We show that the electrochemical polarization leads to in situ construction of the LNO@Pt core–shell structure, significantly suppressing the detrimental effect of La surface segregation on the LNO cathode. The initial peak power density of a single cell with the LNO cathode is 0.71 W cm–2 at 750 °C, increasing to 1.39 W cm–2 by the in situ construction of the LNO@Pt core–shell structure after polarization at 0.5 A cm–2 for 20 h. The LNO@Pt core–shell structure is also highly durable without noticeable performance degradation over the duration of the test for 180 h. The findings shed light on the design and fabrication of highly active and durable LNO-based cathodes for SOFCs.

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“…2 indicates that nanosized Pt (not adjacent to the original TPBs) may undergo migration that may be driven by the oxygen partial pressure changes during the electrochemical reactions. According to the diagram of PtO 2 partial pressure as a function of oxygen partial pressure, 34 without a current load Pt tends to be oxidized and vaporized as gas species in the air at high temperatures. 35 Once the cathodic polarization is applied, the thermodynamic equilibrium partial pressure of PtO 2 is sharply altered at TPBs due to the change of local oxygen partial pressure.…”

Section: Nano Lettersmentioning

confidence: 99%

Conformal Electrocatalytic Surface Nanoionics for Accelerating High-Temperature Electrochemical Reactions in Solid Oxide Fuel Cells

et al. 2019

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Additive implantation of electrocatalysts onto the internal surface of porous cathodes holds great promise to accelerate the electrochemical reactions within solid oxide fuel cells (SOFCs). Here we utilize atomic layer deposition (ALD) to apply dual catalysts with (Mn0.8Co0.2)3O4 and a minute amount of Pt on the cathode consisting of lanthanum strontium manganite (LSM) and yttria-stabilized zirconia (YSZ). Coating this material with optimum ALD layer thickness resulted in a 53% reduction of polarization resistance and a 350% SOFC peak power density enhancement at 750 °C. During the electrochemical operations, the dual catalysts interact synergistically and evolve into superjacent conformal electrocatalytic (Mn0.8Co0.2)3O4 nanoionics with high-density grain boundaries and subjacent discrete nano Pt particles evenly distributed on both the LSM and YSZ. The configuration consequently extends the active electrochemical reaction sites to the entire internal surface of the cathode. For the first time in the field of SOFCs, the present work demonstrates the formation of the electrocatalytic surface nanoionics and its resultant accelerated mass and charge transfer to dramatically boost the cell performance.

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Performance improvement by metal deposition at the cathode active site in solid oxide fuel cells

Cited by 11 publications

References 22 publications

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

Electrochemically Assisted Construction of a La₂NiO_4+δ@Pt Core–Shell Structure for Enhancing the Performance and Durability of La₂NiO_4+δ Cathodes

Conformal Electrocatalytic Surface Nanoionics for Accelerating High-Temperature Electrochemical Reactions in Solid Oxide Fuel Cells

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Performance improvement by metal deposition at the cathode active site in solid oxide fuel cells

Cited by 11 publications

References 22 publications

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

Synergetic Interaction of Additive Dual Nanocatalysts to Accelerate Oxygen Reduction Reaction in Fuel Cell Cathodes

Electrochemically Assisted Construction of a La2NiO4+δ@Pt Core–Shell Structure for Enhancing the Performance and Durability of La2NiO4+δ Cathodes

Conformal Electrocatalytic Surface Nanoionics for Accelerating High-Temperature Electrochemical Reactions in Solid Oxide Fuel Cells

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Electrochemically Assisted Construction of a La₂NiO_4+δ@Pt Core–Shell Structure for Enhancing the Performance and Durability of La₂NiO_4+δ Cathodes