Computational studies of PEO_3-NaClO_4 based solid polymer electrolyte for Na-ion batteries

摘要

Ab initio study based on density functional theory is performed, to describe the effect of the addition of Na salt to polyethylene oxide PEO polymer. Three monomer units of PEO and one molecule of NaClO_4 were taken for calculations. To study the variation in chemical parameters such as electronegativity, chemical potential and chemical hardness of polymer and salt-polymer system HOMO-LUMO compositions and energies were obtained from density of state (DOS) analysis. For quantitative analysis of partial atomic charge distribution on each atom Hirshfield population analyses has been done. Electronics studies have been carried out from density of states (DOS) and partial density of states (PDOS) analysis. From DOS analysis the forbidden energy gap of (PEO)_3 with and without NaClO_4 is traced and found to be reduced by 1.5 eV for polymer-salt system than of polymer alone. This implies that there is increase in sodium cation concentration and hence ionic conductivity in solid polymer electrolyte.