DOI: https://doi.org/10.55373/mjchem.v25i1.108

Keywords: Polymer electrolyte; poly(ethylene oxide); polyurethane; tensile stability; ionic conductivity

Abstract

The tensile stability of materials used for battery fabrication must be given due consideration despite ionic conductivity being a crucial criterion. In this study, the tensile stability and ionic conductivity analysis of solid polymer electrolytes (SPE) of different molecular weights, i.e. poly(ethylene oxide) (PEO) (Mw = 100 and 4,000 kg mol-1) in a polyurethane (PU) blend system, was conducted at ambient temperatures. The semi-crystalline PEO was blended with amorphous PU to reduce the crystallinity of the film, and the conductivity of the system was further enhanced with the addition of lithium perchlorate (LiClO4). The PEO/PU/LiClO4 films at different polymer (PEO100 and PEO4000) and salt concentrations were prepared by the solvent casting method. Tensile tests, Fourier Transform Infrared Spectroscopy (FTIR) and Electrochemical Impedance Spectroscopy (EIS) were used to study the tensile and conductivity behaviours of the system. The optimum elongation at break for the PEO100/PU and PEO4000/PU films were 11.25% and 17.71%, obtained at ratios of 50:50 and 80:20, respectively. The elasticity of the PEO100/PU and PEO4000/PU films increased from 54.697 to 20.948 MPa and from 67.393 to 15.980 MPa, respectively. These results showed that the elasticity of the system was enhanced when PEO and PU were blended together. The optimum conductivity values for PEO100 and PEO4000 were recorded at 3.61 x 10-7 S cm-1 and 1.16 x 10-7 S cm-1, respectively, when 10 wt% and 5 wt% of LiClO4 was added. It can be concluded that the PEO/PU polymer blend electrolyte systems prepared in this study could be efficient polymer electrolytes, especially for battery applications.