Multiscale Modelling of Solid Oxide Cells Validated on Electrochemical Impedance Spectra and Polarization Curves

Solid oxide cells (SOCs) are high temperature energy-conversion devices, which have attracted a growing interest in the recent years. Indeed, this technology presents a high efficiency and a good reversibility in fuel cell (SOFC) and electrolysis (SOEC) modes. Nevertheless, SOCs durability is still insufficient due to performance degradation during operation. In this context, a physics-based model has been proposed to investigate the impact of operating conditions on the electrodes reaction mechanisms and cell performance. This multiscale model has been developed considering a typical cell composed of a dense electrolyte in Y 0.16 Zr 0.84 O 1.92 (8YSZ) sandwiched between an oxygen electrode in La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ -Ce 0.8 Gd 0.2 O 2-δ (LSCF-GDC) and a hydrogen electrode made of Ni-YSZ. The model has been validated on global and local polarizations curves in SOFC and SOEC modes, and electrochemical impedance spectra at the open circuit voltage (OCV). The different contributions arising in the impedance spectra have been identified and discussed.