Solid electrolytes have been regarded as the most promising electrolyte materials for the next generation of flexible electronic devices due to their excellent safety and machinability. Herein, composite solid electrolytes (CSE) with "polymer in ceramic" are prepared by using lithium aluminum titanium phosphate (LATP) as a matrix and modified poly(ionic liquid) as a binder. The results revealed that adding a poly(ionic liquid)-based binder not only endowed good flexibility for solid electrolytes, but also significantly improved the ionic conductivity of the electrolytes. When the content of LATP in the CSE was 50 wt.%, the electrolyte obtained the highest ionic conductivity (1.2 × 10-3 S·cm-1), which was one order of magnitude higher than that of the pristine LATP. Finally, this study also characterized the compression resistance of the composite solid-state electrolyte by testing the Vickers hardness, and the results showed that the hardness of the composite solid-state electrolyte can reach 0.9 ± 0.1 gf/mm2 at a LATP content of 50 wt.%.
Keywords: hardness; ionic conductivity; lithium aluminum titanium phosphate; poly(ionic liquid); solid-state electrolyte.