Performance and degradation of La0.8Sr0.2Ga0.85Mg0.15O3−δ electrolyte-supported cells in single-chamber configuration

• Electrical properties of LSGM2015 electrolyte-supported single-chamber fuel cells.
• Good performance stability of cell after 100 h operating at 650 °C and CH4/O2 = 1.4.
• Strong degradation of cell performance operating for 100 h at 800 °C and CH4/O2 = 1.4.
• Identification of causes of performance degradation by SEM-EDS analysis.

Electrolyte-supported cells were made of a La0.8Sr0.2Ga0.85Mg0.15O3−δ (LSGM2015) electrolyte (200 μm thickness) prepared by ethylene glycol complex solution synthesis, isostatic pressing and sintered at 1400 °C, a Ni-SDC anode, a Sm0.2Ce0.8O3−δ (SDC) buffer-layer between anode and electrolyte, and a La0.5Sr0.5CoO3−δ-SDC cathode. The cells were tested in single-chamber configuration using methane–air mixtures. The results of X-ray diffraction and SEM-EDS showed a single-phase in the electrolyte and conductivities (∼0.01 S cm−1 at 650 °C) close to the typical values. Good cell power densities of 215 and 102 mW cm−2 were achieved under CH4/O2 = 1.4 of at 800 and 650 °C, respectively. However, the cell stability tests indicated that the operating temperature strongly influenced on the cell performance after 100 h. While no significant change in the power density was observed working at 650 °C, a clear performance degradation was evidenced at 800 °C. SEM-EDS revealed an appreciable degradation of the electrolyte and both the electrodes.