A comparison of Li+ transport in dimethoxyethane, poly(ethylene oxide) and poly(tetramethylene oxide) by molecular dynamics simulations

Pure dimethoxyethane (DME), poly(ethylene oxide) (PEO) and poly(tetramethylene oxide) (PTME) and their binary mixtures with LiI were investigated by molecular dynamics simulations (Li/O proportion equal to 1:8). The properties analyzed included the relative occurrence of trans and gauche population for selected torsions, radial distribution functions, mean square fluctuations and mobilities. We studied the relation between the ionic transport process of Li+ and the conformational behavior in DME, PEO and PTME systems. We investigated the solvation shell around Li+ in those systems. The gauche effect of DME and PEO (OCCO torsion) is strongly related to salt addition. This effect is more pronounced in DME-based systems. Li+/O co-ordination occurs in all considered systems. The mobility of the ionic species is larger in DME than in the polymers. In PTME, it is only slightly smaller than in PEO.