Three polyurethane electrolytes, linear polyurethane (LPU),hybrid of linear and hyper-branched polyurethane (MHPU), and low cross-linked copolymer of linear and hyperbranched polyurethane (CHPU) complex with LiClO4, were studied using conductivity, FTIR, Raman, and C-13, H-1, and Li-7 solid-state NMR measurements. The best conductivity value measured at 25 degreesC was 2.7 x 10(-7) s cm(-1) at about a EO/Li ratio of 8 for the LPU electrolytes. At a higher salt concentration (EO/Li = 4), the MHPU and CHPU electrolytes reached its maximum conductivity, 1.35 x 10(-6) and 1.51 x 10(-5) s cm-1, respectively. FTIR, Raman, and C-13 NMR analysis showed that hyperbranched polymer could function as a "solvent" for the lithium salt. Correlation times and the activation energies for the polymer segmental and the lithium hopping motions were determined from the temperature dependence of the spin-lattice relaxation of the polymer (H-1) and lithium (Li-7). The correlation time and activation energy for the lithium hopping motions in the CHPU electrolytes had a relatively low value. This indicated that lithium ion transport was easier in such a system.