Effects of Ni-NCAL and Ni–Ag electrodes on the cell performances of low-temperature solid oxide fuel cells with Sm0.2Ce0·8O2-δ electrolyte at various temperatures

Sea-Fue Wang; Yi-Le Liao; Yung-Fu Hsu; Piotr Jasiński

doi:10.1016/j.ijhydene.2022.09.148

Effects of Ni-NCAL and Ni–Ag electrodes on the cell performances of low-temperature solid oxide fuel cells with Sm0.2Ce0·8O2-δ electrolyte at various temperatures

Abstract

Three low-temperature solid oxide fuel cells are built using Sm0.2Ce0·8O2-δ (SDC) as the electrolyte. Cell A is symmetrical and features Ni–LiNi0.8Co0·15Al0·05O2 (Ni–NCAL) electrodes, Cell B comprises a Ni–NCAL anode and a Ni–Ag cathode, and Cell C is fabricated using a Ni–NCAL cathode and a Ni–Ag anode. The ohmic resistance and polarization resistance (Rp) of Cells B and C are significantly higher than those of Cell A. The reduction of NCAL at the anodes of Cells A and B yields LiOH and Li2CO3 phases, and the Ni particles generated on the surfaces of the NCAL particles improve the catalytic activity of the cells. Li2CO3–LiOH melts at temperatures >450 °C and penetrates the porous SDC electrolyte layer, causing its densification and abnormal grain growth and increasing its ionic conductivity to >0.2 S/cm at low temperatures. The high open-circuit voltages (OCVs) (0.970–1.113 V) of the cells during electrochemical measurements are ascribed to the Li2CO3–LiOH phase which serves as an electron-blocking layer for the SDC electrolytes. As the reduction of NCAL approaches completion, the anode comprises only Ni phase, which hinders the charge transfer process. The triple-phase-boundary (TPB) area at cathode of Cell B is significantly lower than that of Cell A; therefore, the catalytic activity of Cell B for the oxygen reduction reaction is lower than that of Cell A. Consequently, the maximum power density (MPD) of Cell B is less than half of that of Cell A. The large Rp value of Cell C is ascribed to its low TPB area at Ni–Ag anode which has no reaction with H2 during operation. No visible sintering of the SDC electrolyte layer is observed for Cell C; therefore, its ionic conductivity is considerably smaller than those of the electrolyte layers of Cells A and B. The OCVs of Cell C (0.281–0.495 V) are significantly lower than the typical OCVs of ceria-based SOFCs. This is attributed to the porous SDC electrolyte layer of Cell C. The large Rp values and the low OCVs contribute to the low MPDs of Cell C at various temperatures.

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Authors (4)

Sea-Fue Wang
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology
Yi-Le Liao
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology
Yung-Fu Hsu
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology
Piotr Jasiński prof. dr hab. inż.

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Keywords

SOLID OXIDE FUEL CELL NCAL ELECTRODE POLARIZATION CELL PERFORMANCE

Details

Category:

Articles

Type:

artykuły w czasopismach

Published in:

INTERNATIONAL JOURNAL OF HYDROGEN ENERGY no. 47, pages 40067 - 40082,
ISSN: 0360-3199

Language:

English

Publication year:

2022

Bibliographic description:

Wang S., Liao Y., Hsu Y., Jasiński P.: Effects of Ni-NCAL and Ni–Ag electrodes on the cell performances of low-temperature solid oxide fuel cells with Sm0.2Ce0·8O2-δ electrolyte at various temperatures// INTERNATIONAL JOURNAL OF HYDROGEN ENERGY -Vol. 47,iss. 94 (2022), s.40067-40082

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