Molecular dynamics modeling the Li-PolystyreneTFSI/PEO blend

Abstract

Classical Molecular Dynamics (MD) simulation studies of the single-ion conductor lithium poly(4-styrenesulfonyl(trifluorosulfonyl)imide) (PSTFSI) are for the first time presented here. The polymer electrolyte system comprises anions which are covalently bonded to a polymer backbone, thus rendering very high positive transport numbers. The studies here include a quantum chemistry based force field generation for this system and MD simulations of PSTFSI and a blend between PSTFSI and poly(ethylene oxide) (PEO). The simulations show that PEO acts as a very good solvent for the Li-ions, and that the transport properties are similar to Li-salt/PEO electrolytes at room temperature conditions, while pure PSTFSI has very little Li mobility at all. Realistic Li diffusion coefficients of ~ 1 × 10− 13 m2 s− 1 were generated for the PSTFSI/PEO blend.