Solid Polymer Electrolyte Based on Pluronic P123 Triblock Copolymer‐Siloxane Organic‐Inorganic Hybrid

A novel organic‐inorganic hybrid electrolyte based on poly(ethylene oxide)‐poly(propylene oxide)‐poly(ethylene oxide) triblock copolymer (Pluronic P123) complexed with LiClO₄ via the co‐condensation of an epoxy trialkoxysilane and tetraethylorthosilicate was prepared. Characterization was made by a variety of techniques including powder X‐ray diffraction, AC impedance, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and multinuclear solid state NMR measurements. The hybrid with [O]/[Li] = 16 exhibited a mesophase with a certain degree of ordering, which arose by the self‐assembly of P123 with the silica network. The P123 triblock copolymer acts as a structure‐directing surfactant to organize with silica networks and as a polymer matrix to dissolve alkali lithium salts as well. The DSC results indicated the formation of transient crosslinking between Li⁺ ions and the ether oxygens of the EO and PO segments, resulting in an increase the T_g with increasing salt concentrations. Variable temperature ⁷Li‐{¹H} MAS NMR spectra revealed the presence of two different local environments for lithium cations, probably due to the lithium cations in the polymer‐rich domain and in the silica‐rich domain, respectively. A combination of XRD and conductivity results suggests that the drastically enhanced conductivity for the ordered hybrid electrolyte is closely related to the formation of mesophase, which may provide unique Li⁺ conducting pathways.