Performance and short-term stability of single chamber SOFCs based on La0.9Sr0.1Ga0.8Mg0.2O3-d electrolyte

Abstract

In the present work, the performance of La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte-supported SOFCs was evaluated under single-chamber conditions. For this purpose, two single cells, one with and the other without Sm0.2Ce0.8O3−δ (SDC) buffer layer between anode and electrolyte, were studied in order to determine and compare the performance and short-term stability of cells under single-chamber conditions. The reactivity of the Ni-SDC anode with SDC (for the cell with buffer layer) and the LSGM electrolyte (for the cell without buffer layer) were studied by X-ray diffraction. The reaction between Ni and LSGM during anode sintering and cell operation leads to a substantial loss in the cell performance when no buffer layer is present. As a result, maximum power densities of 246 and 132 mW cm−2 were obtained for the buffered and non-buffered cells respectively, at 800 °C, under optimized gas composition (CH4/O2 = 1.2) and a total flow rate of 400 ml min−1. After 55 h operating at 750 °C and 6 thermal cycles, the performances of both cells were decreased around 25–30 mW cm−2.