Studies on solid-state polymer composite electrolyte of nano-silica/hyperbranched poly(amine-ester)

A new solid-state polymer composite electrolyte based on hypergrafted nano-silica (SiO 2 -g-HBPAE)/hyperbranched poly (amine-ester) (HBPAE) doped with lithium perchlorate (LiClO 4 ) was studied in this paper. The N , N -diethylol-3-amine-2-methyl methylpropionate monomer was firstly synthesized by methyl methacrylate (MMA) and diethanolamine through Michael addition reaction and then self-condensed on the surface of nano-silica pretreated by 3-aminopropyltriethoxysilane (APTES) and MMA. The synthetic procedure of the monomers and SiO 2 -g-HBPAE/HBPAE was traced by fluorescence spectra. The size and grafting ratio of SiO 2 -g-HBPAE were characterized by transmission electron microscopy, static light scattering and thermogravimetric analysis. Incorporating SiO 2 -g-HBPAE to HBPAE could not only decrease the glass transition temperature of polymer according to the differential scanning calorimetry characterization, but also increase the elastic and viscosity modules indicated by rheological measurement results. Electrochemical properties of SiO 2 -g-HBPAE/HBPAE/LiClO 4 were also investigated. The conductivity of SiO 2 -g-HBPAE/HBPAE with 50 wt% LiClO 4 reached 1.4 × 10 −5  S/cm at 30 °C and 10 −3  S/cm at 100 °C. The lithium-ion transference number of synthesized hyperbranched electrolyte can be up to 0.55.