Conductivity and Dielectric Study of Polylactic Acid- Lithium Perchlorate Solid Polymer Electrolyte Film

Abstract

The solid polymer electrolyte (SPE) consists of polylactic acid (PLA) with different compositions of lithium perchlorate (LiClO4) were prepared by using the solution casting method. The conductivity and dielectric properties of the SPE system were studied by using an impedance spectroscopy technique with a frequency ranging from 0.1 Hz to 100 MHz. The optimum composition of the LiClO4 in the PLA based electrolyte system is 50 %. The highest ionic conductivity value of the PLA-LiClO4 electrolyte is 2.66 x 10-5 Scm-1. The dielectric permittivity, ɛ′ shows high magnitude in the lower frequency due to electrode polarization (EP) effect and become to decrease at high frequency. The magnitude of ɛ′ increases up to 50 % of LiClO4 in the electrolyte system. The loss tangent was used to measure the relaxation time of the electrolyte system. The shortest relaxation time is PLA- LiClO4 polymer electrolyte system is 7.98 × 10−6 s. The electric modulus, M′ and M′', increases with frequency, indicating that the force of charge carriers increases in depletion and accumulation regions at room temperature.