Enhanced Ionic conductivity and optical transmissivity of functionalized ZrO2/PVdF-HFP hybrid electrolyte for energy efficient windows

•Functionalized ZrO2/PVdF-HFP hybrid electrolyte was synthesized.•ZrO2 improved the ionic conductivity of electrolyte by four orders of magnitude.•MPS functionalized-ZrO2 enhanced the optical transmittance of the electrolyte.

A hybrid electrolyte for energy efficient windows was fabricated by incorporating functionalized zirconium oxide (ZrO2) nanocrystals into poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) and complexed with lithium trifluoromethanesulfonate (LiCF3SO3). Ionic conductivity of the electrolyte increased by 4 orders of magnitude upon addition of a phase-pure cubic ZrO2 that was synthesized by reacting zirconium (IV) isopropoxide and benzyl alcohol at 210 °C for 3 days. Functionalizing the nanocrystal with a vinyl group-containing ligand, at a ligand-to-ZrO2 molar ratio of 0.1:1, enhanced the electrolyte's optical transmittance doubly while maintaining its high ionic conductivity of 1.78×10−3 S cm−1 at a loading of 3.85 ZrO2 wt%. Further addition of the ligand significantly decreased the ionic conductivity but kept a high optical transmittance. This new nanocomposite electrolyte with further tuning has the potential to be next generation electrolyte for energy efficient windows.