Student Name: Jaechan Pyo

Advisor: Dr. Claudio Di Leo

Milestone: PhD Thesis Proposal

Degree Program: Aerospace Engineering

Title: Continuum Multiphysics Modeling of Deformation, Damage, and Microstructural Evolution in Energy Storage Materials

Abstract: The growing demand for energy storage spans a broad range of applications with fundamentally different performance requirements. In transportation, the continued electrification of vehicles motivates battery technologies with high specific energy density, including all-solid-state batteries employing high-capacity electrode materials such as silicon. In stationary applications, increasing energy demand and the need for efficient storage and utilization of thermal energy motivate technologies such as thermochemical energy stor- age, where salt-hydrate materials offer high volumetric energy density and long-duration storage with way economical cost compared with Li-ion batteries. Despite their distinct energy-storage mechanisms, these material systems share an important mechanics challenge. Many materials capable of storing large amounts of energy undergo substantial changes in chemical composition during operation, which are accompanied by correspondingly large deformations. The resulting stresses, damage, and evolution of the internal microstruc- ture can alter transport pathways and ultimately limit the cycling stability and realizable energy-storage performance of the material. Large deformations in energy-storage materials give rise to coupled physical phenomena that influence both mechanical integrity and transport behavior. In electrochemical batteries, for example, heterogeneous lithiation can produce non-uniform strain and stress fields, which in turn affect electrochemical reaction and transport through changes in local chemical potential and ion-transport pathways. In thermochemi- cal energy storage, hydration and dehydration involve coupled heat and mass transport through a porous microstructure whose evolving porosity and interparticle contact determine the effective thermal conductiv- ity of the material. These examples demonstrate that the macroscopic performance of high-energy-density storage materials cannot be understood solely from their intrinsic material properties. Instead, predictive continuum models must account for the evolution of internal microstructure, stress, and damage and their coupling with chemical and thermal transport. In this proposal, two different energy-storage material systems are investigated, namely amorphous silicon (a-Si) anodes for all-solid-state batteries (ASSBs) and SrBr2 hydrates for thermochemical energy storage. ~(omitted due to words limit)~ A key unresolved challenge in these materials is predicting the evolution of microstructure during elec- trochemical and thermochemical cycling. To address this challenge, the present frameworks will be extended to incorporate evolving mechanical and thermo-chemical contact between particles, allowing new contacts to form and transport pathways to develop as the material undergoes large reaction-induced deformation. The resulting framework will therefore permit initially discrete particles to merge into connected material domains, while subsequent separation and fracture are captured through phase-field damage. In this manner, the evolving microstructure, including the formation and loss of contacts, changes in transport pathways, and development of damage, can be predicted directly during cycling. The framework will then be used to investigate how microstructural design parameters, including particle morphology and composition, binders, and prescribed defects, may be used to control stress redistribution and damage evolution. Together, these developments will provide a predictive approach for designing evolving microstructures that maintain me- chanical integrity and transport performance in high-energy-density storage materials.

Date and time: 2026-09-22, 12:00 PM to 2:00 PM

Location: Weber200

Committee:
Dr. Claudio Di Leo (advisor), School of Aerospace Engineering
Dr. Christos E. Athanasiou, School of Aerospace Engineering
Dr. Kennedy J. Graeme , School of Aerospace Engineering
Dr. Matthew T. McDowell, School of Materials Science and Engineering
Dr. Akanksha Krishnakumar Menon, School of Mechanical Engineering
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