A study on the kinetics of the phase transformation in silicon anodes in lithium ion batteries

Rezazadeh Kalehbasti, Shaghayegh

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Year:: 2019
Contributor:: Rezazadeh Kalehbasti, Shaghayegh (creator); Guduru, Pradeep (Advisor); Maris, Humphrey (Reader); Bower, Allan (Reader); Brown University. School of Engineering (sponsor)
Genre:: theses
Subject:: Atomic force microscopy; Thermodynamics; phase transformation; lithiation; Silicon; Si anode; lithium ion battery; picosecond ultrasonics; phase field model; Cahn-Hilliard; in situ; crystallographic orientation; Mechanics; kinetics; computational analysis; Experiment
Extent:: xiii, 152 p.

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Abstract:: Phase transforming electrode materials are among the most promising candidates for the next generation of high energy capacity lithium ion batteries. Phase transformation in electrodes are often associated with jumps in the stress, compositional strain, and plastic strain. It can result in permanent deformation of active particles and can drive fracture and pulverization. Therefore, it is necessary to be able to predict the phase transformation behavior in electrode materials for a given driving force. In the present thesis, silicon is chosen as a model system for studying the kinetics, thermodynamics, and mechanics of phase transformation due to lithiation. The first cycle lithiation of crystalline silicon is accompanied with a characteristic phase transformation to a metastable amorphous phase with a large volume expansion ratio of about 400%. Previous studies on the reaction between Li and Si have proved it to be crystallographic orientation dependent; however, the literature lacks a systematic experimental approach for determining the kinetics of phase propagation across different crystallographic planes. We introduce Picosecond Ultrasonics (PU) as a non-destructive in situ method for monitoring the phase propagation in silicon while retaining the simple geometry of the sample and maintaining precise control on the kinetic parameters. By integrating PU with electrochemical measurements, the velocity of the phase boundary propagation under diverse driving forces is determined. The volume expansion in the lithiated silicon at different states of charge is measured by conducting in situ atomic force microscopy during lithiation of crystalline silicon with different crystallographic orientations. Utilizing these kinetic parameters, we calibrate a modified Cahn-Hilliard type phase field model for a moving phase boundary problem and extract other relevant parameters governing the phase transformation behavior in Si. The predictions of the model for the evolution of the chemical potential, concentration, stress, and plastic strain during nucleation and phase propagation are carefully investigated. The experimental and numerical approaches utilized in this thesis facilitate a deeper understanding of the performance of electrode materials in high energy density Li ion batteries.
Notes:: Thesis (Ph. D.)--Brown University, 2019

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Citation

Rezazadeh Kalehbasti, Shaghayegh, "A study on the kinetics of the phase transformation in silicon anodes in lithium ion batteries" (2019). Engineering Theses and Dissertations. Brown Digital Repository. Brown University Library. https://repository.library.brown.edu/studio/item/bdr:1129503/

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Engineering Theses and Dissertations

Theses and Dissertations for the Engineering department.
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