Salt concentration dependence of the mechanical properties of LiPF₆/poly(propylene glycol) acrylate electrolyte at a graphitic carbon interface: A reactive molecular dynamics study

Abstract

This reactive molecular dynamics study explores the salt concentration dependence of the viscoelastic and mechanical failure properties of a poly(propylene glycol)/LiPF6‐based solid polymer electrolyte (SPE) at a graphitic carbon electrode interface. To account for the finite‐size effect of interface‐confined SPE films, the properties of two distinct film thicknesses are compared with the respective bulk properties. Additionally, the effect of uniaxial compression in the interface‐normal direction on free energy profiles of Li‐ion SPE‐desolvation is studied. © 2018 The Authors. Journal of Polymer Science Part B: Polymer Physics Published by Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 718–730

Understanding the Electrochemical Stability Window of Polymer Electrolytes in Solid-State Batteries from Atomic-Scale Modeling: The Role of Li-Ion Salts

“…The standard technique for estimating the ESW of SPEs has been using linear sweep voltammetry (LSV), but this has repeatedly shown to overestimate the ESW when testing in real cells has been applied. This is in stark contrast to liquid electrolyte systems, where also tremendous efforts have been made to characterize the formation of solid electrolyte interphase (SEI) layers. − While the last few years have seen large efforts to understand the interfacial chemistry in ceramic electrolyte solid-state batteries, using both experimental − and computational methods, − only a few pioneering studies have been conducted on SPE-based systems. − In this context, we have recently reported an atomic-scale investigation on the stability and reactivity of a set of polymer, viz., PEO, PVA, PEC, PTMC, PCL, polyethylenimine (PEI), and polyacrylonitrile (PAN), at a Li-metal electrode interface. , That study provides an assessment of the polymer stability and insights into the early stages of the SEI layer formation in SPE-based solid-state batteries, advancing the understanding of the corresponding interfacial chemistry. However, a much-needed systematic study of ESWs of the SPEs, in both pristine polymer hosts and Li-salt-doped systems, is yet to be conducted.…”

Salt Effects on the Mechanical Properties of Ionic Conductive Polymer: A Molecular Dynamics Study

“…In contrast to ionic transport properties (e.g., transference number) where much has been understood recently with the help of molecular modeling, − the mechanical properties of ionic conductive polymers are less studied, − in particular, at atomistic scale. Therefore, in this work, we used a model ionic conductive polymer system, i.e., poly­(ethylene oxide)-lithium bis­(trifluoromethane)­sulfonimide (PEO-LiTFSI), and all-atom molecular dynamics (MD) simulations to study the impact of salt concentrations on mechanical properties, including different types of elastic moduli and the viscoelasticity.…”