Effect of glycerin on the physical properties of polyvinyl alcohol/sodium alginate blend

Abstract

Because of the abundance of sodium resources, sodium-ion batteries (NIBs) offer a promising alternative electrochemical energy storage solution. One of the current roadblocks to the development of NIBs technology is a lack of electrode materials capable of reversibly storing/releasing sodium ions for a sufficiently long time. Thus, this work aims to study, theoretically, the effect of glycerin incorporation on polyvinyl alcohol (PVA)/sodium alginate (Na Alg) blend as electrode materials for NIBs. The electronic, thermal, and quantitative structure-activity relationship (QSAR) descriptors of polymer electrolytes based on a blend of PVA and Na Alg and glycerin are the main topics of this work. These properties are examined here using semi-empirical methods and the density functional theory (DFT). Bandgap energy (Eg) is examined because the structural analysis reveals details regarding the interactions between PVA/Na Alg and glycerin. The findings indicate that the addition of glycerin caused the Eg value to drop to 0.2814 eV. The molecular electrostatic potential surface, or MESP, shows the electron-rich and deficit regions throughout the electrolyte system as well as the distribution of molecular charges. Thermal parameters that are studied include enthalpy (H), entropy (ΔS), heat capacity (Cp), Gibbs’ free energy (G), and heat of formation. Additionally, the study examines several QSAR descriptors, such as total dipole moment (TDM), total energy (E), ionization potential (IP), Log P, and Polarizability. The results show that H, ΔS, Cp, G, and TDM increased with increasing temperature and glycerin content. Meanwhile, heat of formation, IP, and E decreased, improving reactivity and polarizability. Additionally, the cell voltage increased to 2.488 V due to glycerin addition. The overall DFT and PM6 calculations of cost-effective PVA/Na Alg based glycerin electrolytes indicate that they can partially replace lithium-ion batteries due to their multifunctionality, but requires further improvement and investigations.