One-step synthesis of composite electrolytes of Eu-doped ceria and alkali metal carbonates

摘要

Europium-doped ceria (EDC, Ce_(0.9)Eu_(0.1)O_(2-δ))/alkaline carbonate (LNC, (Li,Na)_2CO_3) composite ceramics prepared through a one-step citrate-based route were analyzed by powder X-ray diffraction, infrared and laser Raman spectroscopies as well as scanning and transmission electron microscopy. The electrochemical behavior of the electrolyte material was studied by impedance spectroscopy in air, CO_2 and N_2 + H_2 (90/10 vol%, respectively) gas mixtures, in the temperature range 300-600 ℃. The sub micrometric and even nanosized ceramic particles appeared as merged inside the mixed carbonates, with modest grain to grain necking. The EDC/LNC composite electrolytes showed a conductivity of 0.27 S cm~(-1) at 600 ℃ in air, amongst the best ever reported, exceeding the usual requirements for fuel cell applications.