Sr Doped Amorphous LLTO as Solid Electrolyte Material

Amorphous Li0.35La0.55TiO3 (LLTO) shows great promise as solid electrolyte material in all-solid-state Li-ion batteries (ASSLiB). Amorphous LLTO thin films with high stability were successfully synthesized by sol-gel process in our previous work. The ionic conductivity can reach up to 1.88*10−5 S cm−1 at 30 °C. In order to further increase the ionic conductivity to meet the requirements of ASSLiB, cation doping is applied in this study. Specifically, Strontium (Sr) is introduced as dopant and the ionic conductivity reaches 8.38 × 10−5 S cm−1 at 30 °C with 5% of Sr doping, which is about one order of magnitude higher than that of undoped LLTO. It is also confirmed that amorphous LLSTO is stable in direct contact with Lithium and with stability window up to 10 V. Furthermore, the relationship between the structure change along with Sr ratio and ionic conductivity is identified. This could be critical for further study of solid electrolyte materials.