Reduced-temperature redox-stable LSM as a novel symmetrical electrode material for SOFCs

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Based on its reduced-temperature redox-stable phenomenon, the state-of-the-art perovskite oxide La0.8Sr0.2MnO3-δ (LSM) is proposed as a novel symmetrical electrode material for solid oxide fuel cells (SOFCs) at intermediate temperatures. LSM exhibits redox instability at high temperatures (≥850 °C) in agreement with the literature, whereas LSM is stable in both fuel and air conditions at intermediate temperatures (≤800 °C). The electrical conductivity of LSM in both air and humidified H2 (3% H2O) exhibit a semiconductor behavior, and the maximum values are 123.8 S cm−1 and 2.01 S cm−1 at 800 °C, respectively. LSM-Gd0.2Ce0.8O2-δ (LSM-GDC) composite electrode was used to improve the electrochemical performance. The area specific resistance of LSM-based electrode decrease from 3.03 Ω cm2 to 1.44 Ω cm2 in air and from 10.49 Ω cm2 to 5.19 Ω cm2 in H2 at 800 °C by adding mixed ionic-electronic conducting GDC, respectively. The electrochemical performance of symmetrical SOFCs with LSM-based electrodes are dramatically enhanced by more than 120 percent at 800 °C. The LSM-GDC composite electrode delivered optimum electrochemical properties with 140 h long-term stability, demonstrating its potential as both anode and cathode for symmetrical SOFCs at intermediate temperatures.