Zirconium-substituted LiSn₂P₃O₁₂ solid electrolytes prepared via sol–gel method

Li_1.5Sn₂P_2.5Zr_0.5O₁₂ compound was synthesized using a simple and economical water-based sol–gel technique. XRD analysis showed that the compound contains a NASICON-structured rhombohedral crystalline phase and Zr⁴⁺ was successfully substituted into the LiSn₂P₃O₁₂ structure instead of forming impurities. The compound displayed a greater conductivity value compared to the unsubstituted parent compound, LiSn₂P₃O₁₂. The Li_1.5Sn₂P_2.5Zr_0.5O₁₂ compound displayed total conductivity values of 1.32 × 10⁻⁶ S cm⁻¹ at room temperature and 5.77 × 10⁻⁵ S cm⁻¹ at 500 °C. Furthermore, the AC conductivity, σ _AC, was found to increase with rising temperature and the outcomes were discussed using the correlated barrier hopping model. The Li_1.5Sn₂P_2.5Zr_0.5O₁₂ compound was also electrochemically stable up to 5.2 V, which was greater than the unsubstituted parent compound. Meanwhile, the transference number measurement was near to unity and it can be inferred that the majority of mobile charge carriers were ions and anticipated to be Li⁺.