Nanocomposite Electrolytes Using Single-Ion Conducting Fumed Silica

Fumed silica surfaces were chemically modified to form single-ion conductors by attaching lithium-exchanged anionic groups (lithium 2-acrylamido-2-methyl-1-propanesulfonate, LiAMPS) to surface methacrylates on Degussa R711 fumed silica (abbreviated as R711-pLiAMPS). Surface lithium-ion contents varying from 0.7 to 9.1 nm −2 were synthesized. Conductivity and transference number measurements were conducted on nanocomposite electrolytes containing polyethylene glycol dimethyl ether A maximum room-temperature conductivity of S cm −1 was obtained at a surface content of 4.2 nm −2 and a Li:O mole ratio of 1:100 (15.8 wt % filler) with a transference number of 0.59. A maximum transference number of 0.78 was achieved at a surface surface content of 4.2 nm −2 and a Li:O mole ratio of 1:20 (48.5 wt % filler) with a conductivity of S cm −1 . Adding lithium bis(trifluoromethylsulfonyl)imide (LiTFSI) to the samples enhances room-temperature conductivity by more than two orders of magnitude while still maintaining a relatively high transference number.