Lithiated Nanoparticles Doped with Ionic Liquids as Quasi-Solid Electrolytes for Lithium Batteries

This work reports two quasi-solid composite electrolytes based on LiFT (Lithiated Fluorinated Titania) nanopowder and either 1-ethyl-3-methylimidazolium tetrafluoroborate (EMImBF(4)) or 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImTFSI) ionic liquid (IL). In details, LiFT nanopowder is doped with ca. 30 wt% of IL, giving rise to materials with formula LiFT/(EMImBF(4))(0.)(183) and LiFT/(EMImTESI)(0.)(087). The resulting composite electrolytes appear as powder-like solids as the IL is completely absorbed by LiFT. The correlation between structure, thermal properties and long-range charge migration processes of the here proposed electrolytes is investigated by several characterization techniques, as follows: i) differential scanning calorimetry (DSC) and high-resolution thermog-ravimetry (HR-TGA); ii) Fourier-transform infrared spectroscopy in both the medium and the far infrared (FT-MIR and FT-FIR); and iii) broadband electrical spectroscopy (BES). The conductivity of the here proposed composite electrolytes is promising. Indeed, at 30 and 100 degrees C it corresponds respectively to 1.75 x 10(-3) S cm(-1) and 1.05 x 10(-2) S cm(-1) for LiFT/(EMImBF(4))(0.183), and 1.36 x 10(-2) S cm(-1) and 4.42 x 10(-2) S cm(-1) for LiFT/(EMIMITSI)(0.087). Finally, LiFT/(EMImTESI)(0.087) is used to fabricate a coin cell prototype, that is tested by galvanostatic cycling for performance and durability. (C) 2019 Elsevier Ltd. All rights reserved.