system shows the highest ionic conductivity at a much lower coordination ratio. Moreover, Cu 2+ generates higher ionic conductivity than Li + when both of them are at the same low salt concentration (the ratio of PDMS:salt=1 : 0.2 and 1 : 0.4), because of the doubled concentration of counter anions added into the system. Given these results, a mixed Li + and Cu 2+ coordinated system with large portion of Li + and small portion of Cu 2+ could not only increase the ionic conductivity of the material but also enhance the mechanical properties.