article
Electrical properties of Ca-doped ceria electrolytes prepared by proteic sol-gel route and by solid-state reaction using mollusk shells
Registro en:
0360-3199
10.1016/j.ijhydene.2021.02.151
Autor
Nascimento, Rubens Maribondo do
Garcia, Maxwell F. L.
Araújo, Allan Jedson Menezes de
Raimundo, Rafael Alexandre
Grilo, João Paulo de Freitas
Macedo, Daniel Araújo de
Resumen
Ca-doped ceria (CCO) electrolytes were prepared using two processing approaches, proteic sol-gel synthesis using gelatin (SG) and solid-state reaction (SSR). Mollusk shell powder was used in the SSR method as the main source of Ca. Materials sintered at 1350–1450 °C exhibited relative density above 95% and different microstructural features regarding grain size and morphology. Impedance spectroscopy in air revealed a comparatively better total electrical response of materials prepared by the proteic sol-gel route. CCO ceramics prepared by the SG route have bulk conductivity four times higher than the highest conductivity of samples processed by the SSR route. Electrical properties of the grain boundaries of both series of materials reveal distinct oxygen vacancy concentration profiles and space charge potentials. The role of processing route and sintering schedules was discussed taking into consideration the distinct impact of Ca interaction in the grain boundaries