High oxygen ion conduction in some Bi 2O 3-Y 2O 3 (Er 2O 3) solid solutions

Abstract

Highly densified bodies (~ 98 % theoretical density) of the Bi 2O 3-Y 2O 3(Er 2O 3) systems containing 30 moles % Y 2O 3 and 20 moles % Er 2O 3 respectively were prepared from both mixed oxides and coprecipitated oxalates. DC ionic conductivity and impedance complex plane analysis on sintered samples were performed. Under oxygen partial pressure ranging from 1 to 10 Pa was found that, samples containing 30 moles % yttria showed a pure ionic conductivity up to an oxygen partial pressure of 10 −20 Pa. Samples containing 20 moles % erbia, extended its ionic conductivity up to an oxygen partial pressure of 10 −22 Pa. The impedance analysis shows the presence of only one semicircle at low tempertures and it is attributed to bulk conductivity contribution. The conductivity was higher for the Bi 2O 3-Er 2O 3 sintered solid electrolytes, in such a case, a conductivity as high as 1.38 ohm cm at 700ºC was obtained. The activation enthalpy for the conduction process was calculated in the temperature range from 200º to 700ºC in all the cases. Microstructural development in the sintered sample was also studied.