Solid-state composite electrolytes with LATP/TiO₂ ceramic fillers for secondary lithium batteries

This study reports a novel composite electrolyte consisted of polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), TiO₂ nanoparticles, and lithium aluminum titanium phosphate (LATP) ceramic fillers for all-solid-state lithium batteries. The planetary ball milling process was employed to prepare the composite solid electrolyte and homogenize the ceramic fillers into a polymer matrix. The incorporation of TiO₂ and LATP decreased the PVDF-HFP crystallinity and increased the thermal stability as well as the mechanical properties of electrolytes. Of the most significance, the ionic conductivity of the synthesized composite electrolyte under the optimal TiO₂ loading and LATP loading (i.e. 5 %) reached 9.7 × 10⁻⁵ S cm⁻¹ at room temperature, which was two times higher than pure PVDF-HFP electrolyte (4.9 × 10⁻⁵ S cm⁻¹). The associated LiFePO₄/Li half-cell also demonstrates a commendable discharge capacity of 140 mAh g⁻¹ under 0.1C at room temperature. This research presents a promising avenue for fabricating safer solid-state lithium batteries, emphasizing the strategic use of ceramic fillers to improve the ion conductivity and overall battery performance.