Microstructure and electrochemical properties of gadolinia-doped ceria cathodes for SOEC application

摘要

High temperature co-electrolysis (HTCE) technology has become a new research focus in world' s energy field, which can produce synthesis gas by dissociation of CO_2 and H_2O using a solid oxide electrolysis cell (SOEC) .The polarization loss, operational stability and interfacial behavior of SOEC cathode are the key issues for the development of HTCE technology1. In this paper, several high performance CeO_2 based catalysts were introduced into the cathode/electrolyte interface of the SOECs ' and their catalytic performance for high temperature reverse water-gas shift (RWGS) reaction were investigated in detail. By material selection and interfacial structure control, the composite cathode materials with higher performance for HTCE were developed successfully. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the crystallinities and structure of the samples. Cathode supported cells with different CeO2 based cathodes were studied by electrochemical impedance spectroscopy (EIS).The results showed that the electrode polarization loss in the HTCE process were smaller than that of the conventional Ni-YSZ cathode. Based on the above results, the mechanisms of HTCE's electrochemical reaction were investigated by the material characterization coupled with electrochemical measurements..