The phase stability and electrical conductivity of Bi2O3 ceramics stabilized by Co-dopants

► All Bi0.76Y0.24−xMxO1.5+δ reported a lower sintering temperature than Bi0.76Y0.24O1.5. ► Lattice constant of Bi0.76Y0.24O1.5 rose with dopants of Gd3+, Sc3+, or Zr4+, but not Nb5+. ► Bi0.76Y0.20Zr0.04O1.5+δ ceramic has the electrical conductivity of 0.55 S cm−1 at 700 °C. ► Co-doped Bi2O3 ceramics have greater conductivities than single-dopant counterparts. ► The larger conductivity may be triggered by the larger lattice constants.