Three dimensional characterization of nickel coarsening in solid oxide cells via ex-situ ptychographic nano-tomography

Angelis, Salvatore De; Jørgensen, Peter Stanley; Tsai, Esther H. R.; Holler, Mirko; Kreka, Kosova; Bowen, Jacob R.

doi:10.1016/j.jpowsour.2018.02.031

Cited by 39 publications

(42 citation statements)

References 49 publications

(57 reference statements)

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“…The probable cause of the anisotropy is the nickel particles coarsening [37][38][39] and migration that was observed in our previous research [23,24,40] as well as by other research groups [18,41]. During the long-term operation, nickel particles migrate from the anode electrolyte interface toward the anode surface.…”

Section: Resultsmentioning

confidence: 92%

An Anisotropic Microstructure Evolution in a Solid Oxide Fuel Cell Anode

Brus

Szmyd

2020

Nanoscale Res Lett

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The presented research shows that the long-term operation of a solid oxide fuel cell can lead to substantial anisotropic changes in anode material. The morphology of microstructure in the investigated stack was observed before and after the aging test using electron nanotomography. The microstructural parameters were estimated based on the obtained digital representation of the anode microstructure. Anisotropy was discovered in two of the three phases that constitute the anode, namely nickel and pores. The third component of the anode, which is yttriumstabilized zirconia, remains isotropic. The changes appear at the microscale and significantly affect the transport phenomena of electrons and gasses. The obtained results indicate that the reference anode material that represents the microstructure before the aging test has isotropic properties which evolve toward strong anisotropy after 3800 h of constant operation. The presented findings are crucial for a credible numerical simulation of solid oxide fuel cells. They indicate that all homogeneous models must adequately account for the microstructure parameters that define the anisotropy of transport phenomena, especially if microstructural data is taken from a post-operational anode.

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Section: Resultsmentioning

confidence: 92%

An Anisotropic Microstructure Evolution in a Solid Oxide Fuel Cell Anode

Brus

Szmyd

2020

Nanoscale Res Lett

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“…The effect of this process will lead to the disconnection of pathways connected through small bottlenecks while a more stable behavior during operation will be observed for wider pathways characterized by low curvature resulting in an overall decrease in percolation but an increase of the characteristic pathway diameter for the remaining Ni pathways. De Angelis et al [46] used x-ray tomography for investigating Ni/YSZ cermets evolution. They observed that nickel coarsening leads to a loss of nickel connectivity and an improvement in connectivity through the pore phase.…”

Section: Discussionmentioning

confidence: 99%

3D Microstructural Characterization of Ni/YSZ Electrodes Exposed to 1 Year of Electrolysis Testing

Trini

Jørgensen²,

Bentzen³

et al. 2019

J. Electrochem. Soc.

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“…This latter phenomenon represents a significant contribution to the global cell degradation [19]. Indeed, it has been shown that the Ni-YSZ cermet is subjected under operation to a Ni agglomeration resulting in a phase coarsening and a migration changing the Ni distribution in the electrode [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Degradation of Ni-YSZ Electrodes in Solid Oxide Cells: Impact of Polarization and Initial Microstructure on the Ni Evolution

Monaco

Hubert

Vulliet

et al. 2019

J. Electrochem. Soc.

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Two types of solid oxide cells with different Ni-YSZ cermet microstructures have been aged in electrolysis and fuel cell modes for operating times ranging from 1000 to 15000 hours. The pristine and aged cermets have been reconstructed by synchrotron X-ray holotomography. Nickel agglomeration has been observed in the bulk of the operated samples inducing a significant loss of triple phase boundary lengths. The inspection of the microstructural properties has confirmed the stabilizing role of YSZ on Ni coarsening. Furthermore, the gradients of properties quantified at the electrolyte interface have revealed a depletion of Ni only in the electrochemically active region of the electrode. The process is strongly promoted for a coarse cermet microstructure when operated under electrolysis current. The evolution of the microstructural properties has been implemented in an in-house multiscale model. The simulations have shown that the loss of performance is dominated by the depletion of Ni in case of a coarse microstructure. Thanks to the computations, it has been shown that the Ni depletion is controlled by the cathodic overpotential. To explain this dependency, it has been proposed that the accumulation of oxygen vacancies in the double layer could deteriorate the Ni/YSZ interface and trigger the Ni depletion.

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Three dimensional characterization of nickel coarsening in solid oxide cells via ex-situ ptychographic nano-tomography

Cited by 39 publications

References 49 publications

An Anisotropic Microstructure Evolution in a Solid Oxide Fuel Cell Anode

An Anisotropic Microstructure Evolution in a Solid Oxide Fuel Cell Anode

3D Microstructural Characterization of Ni/YSZ Electrodes Exposed to 1 Year of Electrolysis Testing

Degradation of Ni-YSZ Electrodes in Solid Oxide Cells: Impact of Polarization and Initial Microstructure on the Ni Evolution

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