Conductivity enhancement of polyacrylonitrile (PAN)-based electrolytes was performed by addition of the cascade compounds with one amino and three or four nitrile groups to the matrices. The conductivity of the electrolytes with the cascade compounds was about one order higher than that of the additive-free one. DSC measurements of the electrolytes and FT-IR results from the model solution systems suggested that the additives acted as a dissolution enhancer for the lithium salt in the electrolytes. Electrochemical stability of the cascade compounds was estimated from cyclic voltammetry technique. The potential window of the compounds was over 4 V for the compounds with one amino and three nitrile groups and over 5 V for one with four nitrile groups. Polarization behavior of a lithium electrode was also investigated in the additive-free electrolyte and the electrolytes with the additives. The exchange current density of the lithium electrode in the electrolyte with the additives was about two orders higher than that in the additive-free one. Deposition and stripping processes of lithium in the electrolyte with the additive were also demonstrated with cyclic voltammetry measurements.