PEO/PVA/LiOH Solid Polymer Electrolyte Prepared via Ultrasound-assisted Solution Cast Method

Most solid polymer electrolytes (SPEs) still suffer from low ionic conductivity at room temperature, which may be caused by the inhomogeneity of polymer blend and Li-salt. Here, polyethylene oxide (PEO), polyvinyl alcohol (PVA), and lithium hydroxide (LiOH) SPEs were prepared by an ultrasonic method to improve the ionic conductivity and shorten the synthesis time. This procedure has successfully yielded a flexible, transparent, and homogeneous SPEs, which were thermally stable at fairly high temperature as revealed from thermogravimetric analysis (TGA). These samples also showed relatively high ionic conductivity at room temperature with the highest conductivity of 1.25 × 10−4 S/cm and low activation energy of 0.253 eV demonstrated by sample with 2 wt% LiOH loading. Moreover, this sample was also stable in the measured voltage range, i.e., -5 to 5 V. DFT calculation showed that strong intermolecular charge transfer was present in the interaction between Li+ ion with PVA and PEO chain.