PURPOSE: To obtain an ion conductor whose ion conductivity is higher than that of YSZ, and suitable for the solid electrolyte of a solid fuel cell, by specifying the composition consisting of ZrO2, Sc2O3, and A2O3 (where A is Tm, Dy, or Tb).
CONSTITUTION: This ion conductor is of the composition of (1-x-y) ZrO2-xSc2O3- yA2O3 (where 0<x+y≤0.16, x>0, and y>0), and the ion conductivity especially at a low temperature is higher than that of YSZ. This ion conductor can be made by a sintering method by a normal solid phase reaction. In this ion conductor, the adding amounts of the main dopant Sc2O3 and the auxiliary dopant A2O3, are limited so as to improve the stability of the cubic crystal, and it has a characteristic of little change with the passage of time. Furthermore, the mechanical strength to the thermal cycle is high, and a solid fuel cell which can be used practically can be obtained by using such an ion conductor as a solid electrolyte.
IWATA TSUNEKAZU
TAJIMA YUKIMICHI
