Investigation of Li-Ion Hopping in Ionic-Liquid-Incorporated Methyl Cellulose/Carboxymethyl Cellulose Solid Polymer Electrolyte: A Molecular Simulation Insight

Solid polymer electrolytes (SPEs) of cellulose and its derivatives are known for their use in next-generation Li-ion battery electrolytes, as they are safe and environmentally friendly. Incorporating an ionic liquid into its polymeric mixture can significantly improve the overall ionic conductivities. In the present study, molecular dynamics simulations were performed to investigate the ion diffusion mechanism in the ionic liquid incorporated SPE of cellulose derivatives. Amorphous models of methyl cellulose and carboxymethylcellulose with various ratios of ethylmethylimidazolium acetate ([EMIM][CH₃COO]) and LiClO₄ salts were chosen to be representative models. The coordination number of acetates significantly increases as the concentration of the ionic liquid increases. The Li⁺ ion is more attracted to acetate while losing its interactions with polymers and ClO₄^-.