Transferable, Polarizable Force Field for Electrolytes, Protic Ionic Liquids and Deep Eutectic Solvents

Abstract

The transferable, polarizable CL&Pol force field for aprotic ionic liquids presented in our previous study (J. Chem. Theory Comput. 2019, 15, 5858, DOI: 10.1021/acs.jctc.9b00689) is extended to electrolytes, protic ionic liquids, deep eutectic solvents, and glycols. These systems are problematic in polarizable simulations because they contain either small, highly charged ions or strong hydrogen bonds, which cause trajectory instabilities due to the pull exerted on the induced dipoles. We use a Tang-Toennies function to dampen, or smear, the interactions between charges and induced dipole at short range involving small, highly charged atoms (such as hydrogen or lithium), thus preventing the "polarization catastrophe". The new force field gives stable trajectories and is validated through comparison with experimental data on density, viscosity, and ion diffusion coefficients of liquid systems of the above-mentioned classes. The results also shed light on the hydrogen-bonding pattern in ethylammonium nitrate, a protic ionic liquid, for which the literature contains conflicting views. We describe the implementation of the Tang-Toennies damping function, of the temperature-grouped Nosé-Hoover thermostat for polarizable molecular dynamics and of the periodic perturbation method for viscosity evaluation from non-equilibrium trajectories in the LAMMPS molecular dynamics code. The main result of this work is the wider applicability of the CL&Pol polarizable force field to new, important classes of fluids, achieving robust trajectories and a good description of equilibrium and transport properties in challenging systems. The transferability and fragment-based approach of CL&Pol will allow ready extension to a wide variety of protic ionic liquids, deep eutectic solvents and electrolytes.

Effect of side chain modifications in imidazolium ionic liquids on the properties of the electrical double layer at a molybdenum disulfide electrode

“…In order to avoid the polarization catastrophe, the electrostatic interactions between hydrogen atoms in hydroxyl group and all Drude dipoles are damped by using a Tang-Tonnies function. 57 The Thole screening parameter and non-bonded parameters for hydroxyl and benzyl group are refined to provide better agreement with experimental viscosity data.…”

Molecular Interactions between Ionic Liquid Lubricants and Silica Surfaces: An MD Simulation Study

“…Molecular dynamics simulations were carried out with GROMACS 2020 and DL_POLY 2.20 packages 24−29 from initial configurations generated by Packmol 30 and fftool software. 31 The ionic liquids and PEG200 (Table 1) were modeled with CL&P and OPLS-AA force fields. The parameters used in all MD simulations are given in Tables S1 and S6 in the Supporting Information (SI).…”

The sensitive aspects of modelling polymer–ceramic composite solid-state electrolytes using molecular dynamics simulations

“…23,24 The slab was chosen to have a (100) orientation and a c-shift equal to 0.09 (as defined in the SlabGenerator class in Pymatgen), according to the surface energy analysis by Thompson et al 25 Thereafter, a 3 Â 3 Â 3 LLZO slab was generated that was used in all simulations. Next, fftool 26 was used to assign partial charges to LLZO atoms and create a LAMMPS data file that was then used to generate the polymer-ceramic interface. In order to generate initial polymer coordinates and assign simulation parameters, the Enhanced Monte Carlo code 27 was used.…”

“…Chem. Phys., 26,[6216][6217][6218][6219][6220][6221][6222][6223][6224][6225][6226][6227] This journal is © Owner Societies 2024 study constitute a step forward towards more accurate and reproducible simulations of ceramic-polymer interfaces, which is particularly relevant in the field of all solid-state batteries.…”