Synthesis and characterization of Y2O3 doped Na–β″-Al2O3 solid electrolyte by double zeta process

Y2O3 doped Na–β″–Al2O3 was firstly synthesized by double zeta process with Al2O3, Na2CO3, Li2CO3 and Y2O3 as the starting materials. Effects of the Y2O3 content on the microstructure and mechanical and electrical properties of the Na–β″-Al2O3 were studied. Both the density and the bending strength of the samples can be effectively improved by doping Y2O3. Only a part of Y3+ can be diffused into the Na–β″-Al2O3 crystal lattice, and the rest of Y3+ form the solid solution with Al2O3 in the grain boundaries, which restrains the grain growth and accelerates the densification of samples during the sintering process. The optimal amount of doping is 0.5 wt%, the bending strength and conductivity are approximately 16% and 52% higher compared to the un-doped samples, respectively.