Study of high active and redox-stable La0.9Ca0.1Fe0.9Nb0.1O3-δ/Sm0.1Ce0.9O2−δ composite ceramic electrode for solid oxide reversible cells

Abstract

In this paper, the catalytic activity of a ferrite/ceria composite ceramic fuel electrode La0.9Ca0.1Fe0.9Nb0.1O3-δ/Sm0.1Ce0.9O2−δ (LCFNb/SDC) for solid oxide reversible cells (SOCs) is studied by using YSZ (Zr0.84Y0.16O2-δ) and LSM/YSZ (LSM(La0.8Sr0.2MnO3-δ)) as electrolyte and oxygen electrode, respectively. The asymmetrical LCFNb/SDC|YSZ|LSM/YSZ cells are prepared and evaluated electrochemically by using DC (cyclic voltammetry (CV) and galvanostatic) and AC impedance techniques in 50% CO: 50% CO2 at the fuel electrode compartment. XRD results indicate LCFNb in the composite fuel electrode is stable in CO and CO2 at high temperature and the LCFNb/SDC membane fuel electrode prepared by infiltration method presents high performance towards CO2 reduction and CO oxidation. The polarization resistance under open circuit in a 50% CO: 50% CO2 gas composition at 800°C is 0.97Ωcm2. However, both the CV and polarized impedance data show that the cell performance is higher for the electrolysis of CO2 than for the oxidation of CO. The polarization resistance in 50% CO: 50% CO2 at 1.4V at 800°C is 0.39Ωcm2. Notably, the cell shows a highly stable activity towards CO2 electrolysis at different applied voltages at the temperature of 800°C.