Author

Wei Shang

Date of Award

Fall 2021

Document Type

Open Access Thesis

Department

Chemical Engineering

First Advisor

Ralph White

Abstract

An irreversible capacity loss will take place in lithium ions batteries due to the solid electrolyte interface (SEI) creating, which consumes the active lithium and reduces solvent. SEI is either good since it can prevent further electrolyte decomposition or bad for lessening batteries' lifetime. Mathematical modeling of SEI formation is done within a porous electrode to model an empirical battery in the x-direction.A solid electrolyte interphase (SEI) growth model is developed in a mixed-mode which contains solvent diffusion through the SEI layer and its corresponding kinetics of solvent reduction at the electrode surface. The governing equations are numerically solved by the Landau transformation, which makes the moving layer fixed and predicts the open circuit potential, SEI film thickness, and capacity loss. The estimated parameters fitted with experimental data in the literature are computed by COMSOL and MATLAB in this work. Results show that the mixed mode model predicts less capacity loss and thinner SEI thickness due to the growth of the SEI film under open circuit conditions than previously reported by others.

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