PhD Proposal by Francisco Javier Quintero Cortés

Event Details
  • Date/Time:
    • Tuesday September 24, 2019
      11:00 am - 1:00 pm
  • Location: MRDC 3515
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Summaries

Summary Sentence: Engineering Interfaces to Control Phase Transformations in Lithium-based Battery Components

Full Summary: No summary paragraph submitted.

 

THE SCHOOL OF MATERIALS SCIENCE AND ENGINEERING

 

GEORGIA INSTITUTE OF TECHNOLOGY

 

Under the provisions of the regulations for the degree

DOCTOR OF PHILOSOPHY

on Tuesday, September 24, 2019

11:00 AM
in MRDC 3515

 

will be held the

 

DISSERTATION PROPOSAL DEFENSE

for

 

Francisco Javier Quintero Cortés

 

"Engineering Interfaces to Control Phase Transformations in Lithium-based Battery Components"

 

 

Committee Members:

 

Prof. Matthew T. McDowell, Advisor, ME/MSE

Prof. Hamid Garmestani, MSE

Prof. Meilin Liu, MSE

Prof. Juan Pablo Correa-Baena, MSE

Prof. Hailong Chen, ME

 

Abstract:

 

Next-generation lithium-based batteries will deliver higher energy densities than today’s lithium-ion batteries with significantly reduced safety risks. This higher energy density will come from using lithium metal anodes or lithium-rich alloys. A major challenge with these materials is that the phase transformations associated with their use can severely limit battery durability. In this thesis, I will investigate the phase transformations that alloying anode materials undergo upon lithiation, as well as the phase transformations that lithium induces at interfaces with other next-generation battery components such as solid electrolytes and current collectors. Beyond understanding lithium-induced phase transformations, I will explore the use of engineered interphases to prevent the negative impacts of these reactions.

 

In the first half of my thesis, I have both characterized battery phase transformations and developed interfacial materials to control such transformations. Specifically, I have developed an interfacial protection layer for unstable solid electrolytes, and I used synchrotron x-ray techniques to study the strain evolution of an alloying anode material. Most solid electrolytes react with metallic lithium to form secondary phases. In the case of sodium super ionic conductors (NASICON) lithium electrolytes, these secondary phases continue to grow and expand at the lithium interface, eventually causing the solid electrolyte to fracture. In order to prevent this, I used a metallic interlayer that regulates the growth of the secondary phases and extends battery lifetime by a factor of 30. Regarding alloying anode materials, they also undergo a phase transformation upon reaction with lithium. This phase transformation generates a large volume expansion that leads to similar mechanical failure and rapid capacity decay. I used operando synchrotron coherent x-ray Bragg diffraction to measure the evolution of strain in a single germanium active material particle during lithiation. The observation of the evolution of compressive stress in these materials will inform the design of anode materials to mitigate the negative impacts of this phase transformation.

 

For the remainder of this thesis, I will further study phase transformations in solid electrolytes and current collectors in solid-state batteries. For my work on solid electrolytes, I will use operando x-ray tomography to track the growth process of the interphase. With respect to current collectors, I will investigate interfacial coatings and biphasic materials to either entirely passivate the current collector or enable it to actively store ions. Together, this work will advance our fundamental understanding of batteries as well as improve the performance of devices.

Additional Information

In Campus Calendar
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Graduate Studies

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Faculty/Staff, Public, Graduate students, Undergraduate students
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Keywords
Phd proposal
Status
  • Created By: Tatianna Richardson
  • Workflow Status: Published
  • Created On: Sep 6, 2019 - 1:40pm
  • Last Updated: Sep 6, 2019 - 1:40pm