Enhanced ionic conductivity and electrochemical stability of Indium doping Li1.3Al0.3Ti1.7(PO4)3 solid electrolytes for all-solid-state lithium-ion batteries

To enhance the ionic conductivity and electrochemical stability of Li1.3Al0.3Ti1.7(PO4)3 (LATP) solid electrolytes, different contents of indium doping Li1.3Al0.3InxTi1.7-x(PO4)3 (LAITP) solid electrolyte powders are successfully synthesized by spray-drying and calcination processes. The characteristic results confirmed by X-ray diffraction, Fourier transform infrared spectrometer, and field emission scanning electron microscope show that the LAITP-0.12 solid electrolyte exhibits a uniform cube-like morphology, an excellent crystallinity, as well as a high compacted density of 2.239 g cm−3 compared to the pure LATP solid electrolyte when the content of indium doping is up to 12 wt. % vs. the pure LATP powders in the terms of the molar ratio. Moreover, the LAITP-0.12 solid electrolyte presents a high ionic conductivity of 1.779 × 10–4 S cm−1 at 30 ºC. The assembled Li/LAITP-0.12/Li symmetric cell can present excellent lithium platting/striping cycle performance for 500 h. Furthermore, the all-solid-state cell assembled with the LAITP-0.12 solid electrolyte shows extremely superior rate performance compared to other cells and delivers a high discharge specific capacity of 149.9 mAh g−1 at 30 ºC at 0.1 C. The surface and the characteristic diffraction peak of the disassembled LAITP-0.12 solid electrolytes exhibits dense cube-likes morphology and no distinct difference after cycles, respectively. Those results suggest that the effective In ion doping strategy may promote the development of the solid electrolytes for all-solid-state lithium-ion batteries.