LAUSR

Abstract Nanocomposite oxygen electrodes consisting of Sr-doped LaMnO3 (LSM) and Ce0.8Gd0.2O1.9 (GDC) are investigated for use in high-temperature solid oxide electrochemical cells (SOCs) to achieve high performance and high durability in steam electrolysis and reversible operations. The nanocomposite electrode structure is realized by using spray pyrolized LSM-GDC nanocomposite particles, which are secondary particles formed by LSM and GDC crystallites. Two LSM-GDC nanocomposite electrodes with different LSM chemical composition, i.e., La0.6Sr0.4MnO3−δ (LS64M) and La0.4Sr0.6MnO3−δ (LS46M), are examined in steam electrolysis operation. The SOC with LS46M-GDC nanocomposite electrode shows superior performance to that with LS64M-GDC nanocomposite electrode; its current density reaches 1.73 A cm−2 at 800 °C at 1.3 V under 40% humidity condition. Also, LS46M-GDC nanocomposite electrode, where LSM had a Sr-rich chemical composition, stably operated in continuous electrolysis mode and in reversible fuel cell and electrolysis modes. The superior performance and durability might be due to the high catalytic activity of LS46M and to its nanocomposite structure with an extensive electrochemical active region.