Investigation on the structural and ion transport properties of magnesium salt doped HPMC-PVA based polymer blend for energy storage applications

The effects of Mg (NO3)2. 6H2O salt on an eco-friendly biopolymer blend matrix comprising hydroxypropyl methylcellulose (HPMC) and poly (vinyl alcohol) (PVA) is presented in this work which is prepared using the solution casting method. Structural, chemical composition (functional moieties), morphological, and thermal features were investigated by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Differential scanning calorimetry (DSC) and thermogravi-metric analysis (TGA). FTIR spectrum and XRD pattern confirmed that the magnesium nitrate salt was dissolved, and complexation was observed through a coordination bond and a hydrogen bond with-OH and-CH groups in the host polymer blend. The glass transition temperature (Tg) values of HPMC:PVA composites are greater than those of the pure blend, demonstrating transient cross-linking. For P0, P2, and P3 samples, the pore diameter and % porosity is calculated, and the morphology of the P4 sample is non-porous and shows ionic conductivity of P4 = 3.25 x 10-4 S/cm at 27 degrees C. Based on the Nyquist plot fitting and FTIR deconvolution methods, it is used to determine the transport characteristics and noticed that the carrier concentration affects the ionic conductivity. The highest conducting electrolyte has been integrated into a primary battery to demonstrate its potential use in energy storage systems.