AbstractSummary: A new hybrid polymer electrolyte system containing polysiloxane and polyether segments has been designed and prepared by epoxide crosslinking. The thermal behavior, structure and ionic conductivity of the hybrid materials were investigated and characterized by differential scanning calorimetry (DSC), 13C solid‐state NMR spectroscopy and alternating current (AC) impedance measurements. Two glass transition temperatures were observed, showing a dependence on the composition and LiClO4/PC content. The miscibility of the polymer components in the hybrid was studied by examining the 1H spin relaxation times in the laboratory frame (T1(H)) and in the rotating frame (T1ρ(H)) with various compositions. Multi‐relaxation T1ρ(H) behavior has been observed, indicative of the presence of structural heterogeneity on the timescale of T1ρ(H). These results are correlated and used to interpret the phenomenon of the conductivity of the lithium ion in the matrix of hybrid networks.Schematic structure of polysiloxane/polyether networks.magnified imageSchematic structure of polysiloxane/polyether networks.