The electrical conduction in the sintered $3Bi_2O_3\cdotWO_3$ solid electrolyte was investigated by measuring the conductivity and ionic transport number. The electrical conductivity was about three to ten times higher than YSZ between 300 and 800℃. D.C. polarization method confirmed that $3Bi_2O_3\cdotWO_3$ was an almost pure ion conductor.
The fcc phase in the rare-earth oxide-$Bi_2O_3$ or $Y_2O_3-Bi_2O_3$ systems has been found to be unstable below about 700℃, but fcc phase in the $3Bi_2O_3\cdotWO_3$ exhibited no transformation even after annealing over 900hrs at 600 and 650℃.
Two samples which had different grain size was found to show almost same conductivity. Thus it was considered that the electrical properties of grain and grain boundary was not so different.
