Optimized lithium-doped ceramic electrolytes and their use in fabrication of an electrolyte-supported solid oxide fuel cell

Abstract

Lithium-gadolinium-doped ceria electrolytes (2–5 mol% of lithium) are prepared by fast and reliable one-pot sol gel combustion synthesis and sintered at low temperature. The aim is to improve the microstructure, electrochemical and power generation of electrolyte-supported intermediate temperature solid oxide fuel cells. Time-of-flight coupled secondary ions mass spectroscopy and transmission electron microscopy reveal the uniform distribution of lithium and the structural modification and surface change induced by the doping. Lithium addition reduces the sintering temperature to 950 °C, and the electrochemical properties compared to the pure gadolinium doped ceria are highly superior. A maximum of 3.59·10−2–1.41·10−1 S·cm−1 for total conductivity are achieved for 3 mol.% of lithium addition at intermediate operative temperature range. An electrolyte-supported solid oxide fuel cell is then fabricated and tested in different gas conditions and operative temperatures. The maximum power density is 359 mW·cm−2 at 668 mA·cm−2 (750 °C). The results demonstrate the reliability, the short time-to-product and the feasibility of both synthesis cycle and electrolyte production for industrial application to develop a cost-effective and marketable fuel cell technology.