New SOFC Cathode: 3D Core–Shell-Structured La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ@PrO_2−δ Nanofibers Prepared by Coaxial Electrospinning

Abstract

3D core–shell La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF)@PrO2−δ nanofibers as a solid-oxide fuel cell (SOFC) cathode with excellent electrochemical properties are directly prepared by coaxial electrospinning. In the LSCF@PrO2−δ nanofibers, the low oxygen reduction reaction (ORR) activity of LSCF can be effectively ameliorated by heterogeneous PrO2−δ. Compared with the LSCF nanostructure, the LSCF@PrO2−δ nanofibers with a 3D core–shell heterostructure effectively suppress the segregation of Sr on the surface and improve the stability of the cathode. Due to the unique microstructure, large specific surface area, and porosity, the LSCF@PrO2−δ nanofibers provide a continuous path for charge transfer and extend the three-phase interface that help to improve the ORR activity of the SOFC cathode. At 700 °C, the area specific resistance of LSCF@PrO2−δ nanofibers reaches 0.076 Ω·cm2, which is reduced by 35 and 60%, compared with 0.117 Ω·cm2 of LSCF nanofibers and 0.192 Ω·cm2 of the LSCF powder. When LSCF@PrO2−δ nanofibers are used as a single-cell cathode, the peak power density reaches 1.17 W·cm–2 at 700 °C, and the voltage decay rate of the single cell is only 0.03% per hour after 100 h of long-term stability test. Therefore, the 3D core–shell LSCF@PrO2−δ nanofibers provide an alternative approach for obtaining the high-performance SOFC cathode.

Nanoscale Intertwined Biphase Nanofiber as Active and Durable Air Electrode for Solid Oxide Electrochemical Cells

“…As shown in the EIS plot in Figure c, the LSCF/GDC NF showed the lowest polarization resistance of 0.125 Ω cm 2 at 600 °C, which is 33.3% and 4 times lower than that of F-LSCF (0.17 Ω cm 2 ) and C-LSCF (0.64 Ω cm 2 ), respectively. More importantly, this value is even lower than that of the electrocatalyst prepared by mechanically mixing of F-LSCF or C-LSCF with GDC (0.33 and 2.2 Ω cm 2 , respectively, Figure S7) as well as representative decorated LSCF-based electrocatalysts (Figure d), ,,− stressing the important role that coupled structure plays on performance. Further, temperature-dependent activity measurement shows R p values of 0.03, 0.06, and 0.33 Ω cm 2 at 700, 650, and 550 °C, respectively (Figure e).…”

Recent advances in catalyst design and activity enhancement induced by a magnetic field for electrocatalysis

“…58 In the ORR, oxygen molecules are electrochemically reduced to water by 4 protons and electrons, accompanied by the generation of electric potential. 59 Due to their high cost, Pt-based precious metals are difficult to apply on a large scale, and the research on low-cost catalysts, especially low platinum and non-platinum electrocatalysts, including advanced platinum alloys, 60 cored–shell structures, 61 carbon-based non-precious metal catalysts, 62 Pd based catalysts, 63 metal oxides, 64 and sulfur compounds, 65 has attracted extensive attention. The magnetic field-assisted assembly of catalysts with unique structures has become a breakthrough direction.…”

Advances and Perspectives on Solid Oxide Fuel Cells: From Nanotechnology to Power Electronics Devices

“…Bai et al used coaxial electrospinning to prepare 3D core–shell heterostructures of PrO 2− δ ‐decorated LSCF (LSCF@PrO 2− δ ). [ 129 ] Compared to simple LSCF nanostructures, LSCF@PrO 2− δ nanofibers ( Figure 12 ) showed improved stability, ensured the provision of a continuous charge‐transfer path and extended the three‐phase interphase to improve the ORR activity, suggesting a potential strategy to develop high‐performance cathodes.…”

“…Figure 12. a) Schematic illustration of operation of a cell with LSCF@PrO 2Àδ cathode, b) SEM micrographs of different cathodes, c) Arrhenius plots plotted by the reciprocal of ASR for different cathodes, d) I-V and I-P curves of cells measured at 700 °C, and e) comparison of power densities of different cells with different cathodes. Reproduced with permission [129]. Copyright 2022, American Chemical Society.…”