Semiconductor ionic Ce0.8Sm0.2O2-δ-Na2CO3 – LiCo0.225Cu0.075Ni0.7O 3-δ composite material as electrolyte for low temperature solid oxide fuel cells

Abstract

Semiconductor ionic electrolytes have obtained much attention because of good ionic conductivity and electrochemical performance. Novel semiconductor ionic NSDC (Ce0.8Sm0.2O2-δ-Na2CO3)-LCCN (LiCo0·225Cu0·075Ni0·7O3-δ) composite materials have been adopted as electrolyte membrane for the first time, in which symmetrical cell composed of NSDC-LCCN membrane is constructed with Ni0·8Co0·15Al0·05LiO2 (NCAl)-pasted Ni foam electrodes. An open circuit voltage (OCV) above 1 V and improved power density are obtained in the NSDC-LCCN cells, which confirms the functionality of the proposed semiconductor ionic materials. Meanwhile, X-ray diffractometer (XRD) and Scanning electron microscope (SEM) analyses identify the phase purity and homogenous nanocomposite morphology of all the NSDC-LCCN materials samples with various mass ratios. The performance illustrated by much more steady instead of transient state evaluation reveals that 3NSDC-LCCN composite electrolyte is most optimum, and the corresponding cell exhibits a considerable maximum power density of 598 mW cm−2 at 550 °C, over five times of that of pure NSDC electrolyte cells. Short-term duration test of 3NSDC-LCCN cell at 550 °C shows that the cell could steadily operate up to ~9 h without obvious degradation at a remarkable current density of 469 mA cm−2, which indicates that NSDC-LCCN composite electrolyte is a promising material for low temperature solid oxide fuel cells.