Electrochemical Impedance Analysis of Ni/CGO10-Based Electrolyte-Supported Cells

Riegraf, Matthias; Dierickx, Sebastian; Weber, André; Costa, Rémi; Schiller, Günter; Friedrich, Kurt

doi:10.1149/09101.1985ecst

Cited by 4 publications

(4 citation statements)

References 32 publications

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“…This behavior is very similar to that described by Riegraf et al. for Ni–GDC electrodes, although the origin of the different slopes is still under debate 29 . However, the similarity indicates that the electrode response is dominated by the Ni–GDC electrode, although the investigated cells in our work have additional gas diffusion impedance from the support that overlaps with the impedance of the Ni–GDC anode.…”

Section: Resultssupporting

confidence: 89%

“…BSD, backscattered electron detector; SEM, scanning electron microscopy under debate. 29 However, the similarity indicates that the electrode response is dominated by the Ni-GDC electrode, although the investigated cells in our work have additional gas diffusion impedance from the support that overlaps with the impedance of the Ni-GDC anode. As can be seen in the distribution of relaxation time in Figure S2, the peak at the lowest frequency shows clear temperature dependence, meaning that gas diffusion in the support (which shows hardly any temperature dependence) is not the only cause of this peak.…”

Section: Single-cell Performancementioning

confidence: 65%

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Boosting intermediate temperature performance of solid oxide fuel cells via a tri‐layer ceria–zirconia–ceria electrolyte

et al. 2022

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Using cost‐effective fabrication methods to manufacture a high‐performance solid oxide fuel cell (SOFC) is helpful to enhance the commercial viability. Here, we report an anode‐supported SOFC with a three‐layer Gd0.1Ce0.9O1.95 (gadolinia‐doped‐ceria [GDC])/Y0.148Zr0.852O1.926 (8YSZ)/GDC electrolyte system. The first dense GDC electrolyte is fabricated by co‐sintering a thin, screen‐printed GDC layer with the anode support (NiO–8YSZ substrate and NiO–GDC anode) at 1400°C for 5 h. Subsequently, two electrolyte layers are deposited via physical vapor deposition. The total electrolyte thickness is less than 5 μm in an area of 5 × 5 cm2, enabling an area‐specific ohmic resistance as low as 0.125 Ω cm−2 at 500°C (under open circuit voltage), and contributing to a power density as high as 1.2 W cm−2 at 650°C (at an operating cell voltage of 0.7 V, using humidified [10 vol.% H2O] H2 as fuel and air as oxidant). This work provides an effective strategy and shows the great potential of using GDC as an electrolyte for high‐performance SOFC at intermediate temperature.

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Section: Resultssupporting

confidence: 89%

Section: Single-cell Performancementioning

confidence: 65%

Boosting intermediate temperature performance of solid oxide fuel cells via a tri‐layer ceria–zirconia–ceria electrolyte

et al. 2022

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“…Similarly, it also can be observed that the MPD value of Cycle 6 is slightly lower than the MPD of Cycle 5. Anode conductivity in Cycle 4 coating may have been increased greatly by the reduction of Ce(IV) into Ce(III) as well in running conditions 39 . The high gas permeability of Cycle 4 has given the advantage to make the performance to be on par with the anode having low gas permeability but with high conductivity.…”

Section: Resultsmentioning

confidence: 99%

Sol‐gel based copper metallic layer as external anode for microtubular solid oxide fuel cell

Shabri

Rudin

Othman

et al. 2022

Intl J of Energy Research

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Solid oxide fuel cell (SOFC) performance depends greatly on the anode conductivity, which in traditional nickel-yttria stabilized zirconia (Ni-YSZ) anode is determined by the Ni content that is infamous for its coking problem under hydrocarbon fuel. Without the use of high content of Ni, anode conductivity can be elevated by adding an external metal layer on top of the anode. In this study, we present the incorporation of copper (Cu) metal layer on top of the anode of micro-tubular SOFC by applying a modified sol-gel method using syringe deposition technique at various chemical compositions and deposition cycles. Cu sol was found best to be made up of 2:1:8 ratio of Cu: citric acid: ethylene glycol, with 1.36 μm metal layer formed at 5 deposition cycle, and no obvious increase in thickness after the fifth cycle. The Cu layer elevated the conductivity by 10 10 times compared to the uncoated anode. However, the coated layer also reduced the gas permeability by 10 times in the anode, which resulted from the blocking of a nano-sized pore in the anode, rather than the micron size pore. This blocking can be resolved by increasing the amount of micron-sized pore by using pore former during anode fabrication. From electrochemical impedance spectroscopy (EIS), Cu coating reduced the ohmic resistance (R ohm ) and charge transfer resistance (R ct ). From the current-voltage curve, the maximum power density (MPD) was found to increase linearly with the increase of the Cu coating cycle, but the value is almost stagnant at 2.3 to 2.5 mW cm À2 when the coating cycle of more than 4 was employed. This suggests that anode gas permeation plays an important role in anode conductivity.The findings from this study suggested that 5 deposition cycle shows to be the optimal coating layer required to achieve the percolation threshold without unnecessary loss in permeability.

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“…ECS Transactions, 111 (6) 1431-1443 (2023) Riegraf et al have also published about the initial performance and long-term stability of electrolyte-supported (Ni-CGO fuel electrode) SoA cells (8). The reported resistance of low frequency processes at 850 °C (H2O/H2 20/80 %) is of 0.1 Ωcm 2 .…”

Section: Introductionmentioning

confidence: 99%

Analysis of the Long-Term Operation of an Electrolyte-supported Solid Oxide Cell Under Co-electrolysis Regime

Lopez de Moragas,

Tsai,

Hauch

et al. 2023

ECS Trans.

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The solid oxide cell technology allows to produce synthesis gas (CO+H2), a precursor for e-fuels and other chemicals. This work reports on the long-term performance of an electrolyte supported cell (Ni-CGO/3YSZ/LSCF-CGO), operated at industrially relevant co-electrolysis conditions (32.5 % H2, 35 % H2O, 8.1 % CO, 24.4 % CO2, -0.5 A/cm2, 815 °C). The cell had a Ni-CGO fuel electrode (~30 μm thick), a 3YSZ electrolyte (~90 μm) and an LSCF-CGO oxygen electrode (~35 μm thick) plus a thin CGO barrier layer in-between. The cell was operated for 2300 h at constant galvanostatic conditions, with an overall degradation of 80 mΩcm2/kh. At the start of the test, the ohmic resistance contributes to almost 90 % of the ASR (area-specific resistance), but the increase in Rp (polarization resistance) is what contributes the most to the increase in total cell ASR during the long-term operation. This increase in ASR is not constant over the entire test time. On the contrary, it is considerably higher during the first 300 hours (180 mΩcm2/kh) and then it levels off and stabilizes to 32 mΩcm2/kh during the remaining approx. 2 kh of the long-term operation. The measured electrochemical impedance spectra showed a decrease in the performance of the Ni-CGO fuel electrode. A possible explanation for the observed fuel electrode degradation was found via SEM-EDS, where a considerable quantity of silicon-containing compounds was found in the active area of the Ni-CGO fuel electrode.

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Electrochemical Impedance Analysis of Ni/CGO10-Based Electrolyte-Supported Cells

Cited by 4 publications

References 32 publications

Boosting intermediate temperature performance of solid oxide fuel cells via a tri‐layer ceria–zirconia–ceria electrolyte

Boosting intermediate temperature performance of solid oxide fuel cells via a tri‐layer ceria–zirconia–ceria electrolyte

Sol‐gel based copper metallic layer as external anode for microtubular solid oxide fuel cell

Analysis of the Long-Term Operation of an Electrolyte-supported Solid Oxide Cell Under Co-electrolysis Regime

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