We describe the interaction behavior between Polyester and Li+ that affects the ionic conductivity on binary electrolyte of lithium perchlorate (LiClO4) blends with Poly(ethylene adipate), (PEA); Poly(1,4-butylene adipate), (PBA); Poly(1,6- hexamethylene adipate), (PHA); and Polycarprolatone (PCL), respectively. The individual four binary blend systems are similar and fully miscible, a different ionic conductivity exists in the binary Polyester electrolyte system corresponds to the result of the different interactions strength between lithium perchlorate (LiClO4) and various Polyesters. The lithium ion is able to coordinate with more functional groups of PEA polymer chain than that in other three polyester chains. Both DSC and FTIR studies demonstrate that the ability of PEA to donate its electron to coordinate with Li+ is significantly stronger than that of PBA, PHA and PCL. Consequently, the maximum ionic conductivity (1.06 x 10(-5) S cm(-1)) at ambient temperature (30 degrees C) occurred at a composition of PEA/LiClO4 (90/10). It is further found that the ionic conductivity of Polyester electrolyte is not only dependent on the electron donation strength of carbonyl group, but also on the molecular structure of Polyester. (C) 2011 Elsevier Ltd. All rights reserved.