Effects of TiO2 doping on Li+-stabilized Na-v"-alumina for energy storage applications

Sodium-ion conductive Li+-stabilized Na-v"-alumina was synthesized by calcinating a mixture of AlO(OH), Na2CO3 and Li2CO3. For additional improvement of the characteristics the ceramic powder was doped with various amounts of TiO2 and sintered at 1400, 1500 and 1600 °C. The effects of doping and sintering temperature were evaluated by measuring fracture strength, ionic conductivity, density, morphology and phase composition. The conductivity was raised from 0.2 to 0.3 S cm−1 at 300 °C by adding 1.5 wt.-% TiO2 to the Na-v"-alumina. By adding 1 wt.-% of TiO2 to the electrolyte material, the characteristic fracture strength s0 was increased from 188 to 277 MPa. Aside from that, changes in the microstructure, due to doping were observed. The altered properties of the ceramic were mainly assigned to changes in the microstructure.