Enhancement of electrical properties of LiTi2(PO4)3 ceramics via trivalent cation doping and microstructure regulation strategies

The solid-phase reaction method was used to prepare ceramics samples based on LiTi2(PO4)3 crystalline phase and doped with five ions of Al3+/Sc3+/Y3+/Cr3+/Ga3+. The crystalline phase structure, sintering properties and electrical properties of the samples were investigated, and the performance differences of different ion-doped Li-Ti-P-O systems were compared. The results showed that all five doped electrolyte samples exhibited a poly-crystalline phase. SEM images revealed that different element-doping had different effects on grain distribution and size. The EDS results demonstrated that Ga3+ and Cr3+ ions were uniformly distributed in the sample, while Al3+/Sc3+/Y3+ ions showed severe segregation. The sample doped with Ga3+ ion had the maximum conductivity of 2.66 x 10-4 S/cm at room temperature, the highest relative density of 94.4% and the minimum activation energy (0.17 eV). From the above results, it can be concluded that Ga3+ ion doping possessed the greatest effect on promoting structural densification and increasing conductivity.