Kinetically Corrected Monte Carlo-Molecular Dynamics Simulations of Solid Electrolyte Interphase Growth.

Joseph W Abbott,Felix Hanke

doi:10.1021/acs.jctc.1c00921

Abstract

We present a kinetic approach to the Monte Carlo-molecular dynamics (MC-MD) method for simulating reactive liquids using nonreactive force fields. A graphical reaction representation allows definition of reactions of arbitrary complexity, including their local solvation environment. Reaction probabilities and molecular dynamics (MD) simulation times are derived from ab initio calculations. Detailed validation is followed by studying the development of the solid electrolyte interphase (SEI) in lithium-ion batteries. We reproduce the experimentally observed two-layered structure on graphite, with an inorganic layer close to the anode and an outer organic layer. This structure develops via a near-shore aggregation mechanism.

Highlights

Understanding and controlling the chemical degradation of liquid electrolytes is key to enhancing the durability of lithium-ion batteries (LIBs)
In our model anode/electrolyte system shown in Fig. 1a), identification of reaction candidates requires the matching of atom, bond and critical distance criteria to the reactant of the corresponding template reaction path
We have focused on ethylene carbonate (EC) due to its ubiquitous use in liquid electrolytes and active anode chemistry at typical voltages in battery cells

Summary

Introduction

Understanding and controlling the chemical degradation of liquid electrolytes is key to enhancing the durability of lithium-ion batteries (LIBs). Even inside its electrochemical stability window, the electrolyte can reduce near the anode during charging. This initiates a cascade of reactions and culminates in the irreversible growth of a passivation layer, the solid electrolyte interphase (SEI).[1] This layer is composed of various inorganic and organic species[2] that contain lithium. Successful simulations of SEI growth must provide a link between the molecular processes and the emergence of a microscopic structure. In this context, they can play a vital role in the in silico design of electrolytes for use in next-generation high performance LIBs

Methods

Results

Discussion

Conclusion