Preparation And Characterization Of Novel Single-ion Conductors Base On Lithium(Trifluoromethyl(S-trifluoromethylsulfonylimino)Sulfonyl)(Benzenesulfonyl)imide Group As Side Chain

Single-ion conductors are a kind of ion conductors with anions fixed to the polymerbackbone or with anion mobilities reduced by large structure or by associations with thechain. Replacing the traditional liquid electrolyte and solid electrolyte with single-ionconductor can be an effective pass to solve the safety issues and overcome the saltconcentration polarization during the using of the batteries.In this paper we synthesized Lithium poly(trifluoromethylsulfonyl)(p-styrenesulfonyl)imide (LiPSTFISI) which containing "S-trifluoromethyl-sulfonylimidegroup" of the fluoroalkylsulfonylimide structure (-SO2-N-S(O)(=NSO2CF3)-) throughsubstituting an "O" atom of the sulfonylimide group (-SO2-N-SO2-) bytrifluoromethylsulfonylimide group (CF3SO2N=). Trifluoromethyl(S-trifluoromethyl-sulfonimide) sulfonylfluoride was used as the intermediate, and three routes were employedfor the synthesis of (trifluoromethyl(S-trifluoromethylsulfonylimino)sulfonyl)(styrenesulfonyl)imide potassium (KSTFISI). Then LiPSTFISI were synthesized bypolymerization and ion exchange of KSTFISI. The Structure of synthetic intermediates andLiPSTFISI were characterized by IR,1H NMR,19F NMR and so on, and the molecularweight of the polymer, monomer’s and polymers’ phase transition (DSC), thermal stability(TG) and XRD were also characterized. Research indicates that the polymers perform asamorphous polymer and have a good thermal stability (Td>170℃). On this basis the solidelectrolyte film (LiPSTFISI/PEO) which the EO/Li+=35was prepared by LiPSTFISIblending with polyoxyethylene (PEO). Then the DSC, TG, XRD, conductivity andlithium-ion transference number of the electrolyte were tested. Studies have shown that theelectrolyte has a high room temperature conductivity (σ=3.3×10－8S cm－1), good thermalstability (Td=267℃), low PEO crystallinity (χc=34.4) and glass transition temperature (Tg=－8℃) and show as single-ion conductor. The studies of this paper have importanceguiding significance for the using of single-ion conductors in lithium ion batteries, as well asdesigning new structure of single-ion conductors.