Durability of symmetric-structured metal-supported solid oxide fuel cells

Abstract

Symmetric-structure metal-supported solid oxide fuel cells (MS-SOFC) with YSZ electrolyte are fabricated with porous YSZ backbone electrodes, stainless steel supports, and infiltrated catalysts on both anode and cathode side. Durability towards aggressive thermal and redox cycling, and long-term operation is assessed. Many sealing material candidates are screened for compatibility with the cell materials and operating conditions, and a commercial sealing glass, GM31107, is selected. LSM/SDCN cells are then subjected to 200 very fast thermal cycles and 20 complete redox cycles, with minimal impact to cell performance. LSM/SDCN and SDCN/SDCN cells are operated for more than 1200 h at 700°C. The seal and cell hermeticity is maintained, and cell ohmic impedance does not change significantly during operation. Electrode polarization increases during operation, leading to significant degradation of the cell performance. In-operando EIS and post-mortem SEM/EDS analysis suggest that catalyst coarsening and cathode Cr deposition are the dominant degradation modes.

Progress in durability of metal-supported solid oxide fuel cells with infiltrated electrodes

“…coarsening) occur to minimize the local surface energy through particle rearrangement and evolution of grain boundaries [37]. Our previous long-term durability tests on LSM/YSZ/SDCN 20 cells revealed rapid performance degradation (70%/1,000 h) which was linked to catalyst coarsening and chromium poisoning of the LSM catalyst [16]. Such magnitude of degradation does not meet the requirements for vehicular applications.…”

“…Initial peak power for the entire batch of cells used in the matrix varied less than 5% and OCV was 1.12 ± 0.02 V at 700 °C in 3% humidified hydrogen. 16 while the lower operating temperature may lead to increased sensitivity of the performance to catalyst evolution, and breakaway oxidation of the metal support (~600 °C) [2,3], which will be addressed in more detail below in this section. Durability of selected cells at different temperatures is summarized in Fig.…”

“…Higher operating temperature may lead to: (1) rapid oxidation of the metal support (≥800 °C) [2,3], (2) accelerated Cr poisoning of the cathode catalyst [2,[13][14][15], and (3) rapid catalyst coarsening [16]. Lower operating temperature constrains the power density.…”

Metal‐Supported Solid Oxide Electrolysis Cell with Significantly Enhanced Catalysis

“…These challenges include oxidation of the metal support, contamination of the active materials with Cr and Si from the metal support, and long‐term mechanical evolution including creep. Our group has developed symmetric structure MS‐SOFC with infiltrated catalysts on both electrodes and demonstrated high performance, rapid thermal cycling, and dynamic‐temperature operation of the cells . Nielsen et al from Technical University of Denmark adopted a relatively thin metal support with thickness of 175 μm and demonstrated high cell performance .…”

Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

“…However, long term testing at an operation at 700 • C and at 0.7 V for 1200 h showed severe degradation with a peak power density loss of 73%. 35 A summary of reported key performances in laboratory scale, using different manufacturing process and materials is provided in Table 13 of the recent MS-SOFC review from 2017 by Krishnan. 1 From the summary it is clear that the performances reported within the present study are superior compared to the reviewed studies in Ref.…”