Investigating interfacial liquid molecular structures using electrochemical 3-dimensional atomic force microscopy

Panse, Kaustubh S

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https://hdl.handle.net/2142/124617 Copy

Description

Title

Investigating interfacial liquid molecular structures using electrochemical 3-dimensional atomic force microscopy

Author(s)

Panse, Kaustubh S

Issue Date

2023-12-18

Director of Research (if dissertation) or Advisor (if thesis)

Zhang, Yingjie

Doctoral Committee Chair(s)

Zhang, Yingjie

Committee Member(s)

• Braun, Paul
• Rodriguez-Lopez, Joaquin
• Perry, Nicola

Department of Study

Materials Science & Engineerng

Discipline

Materials Science & Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

electrochemical 3-dimensional atomic force microscopy

Abstract

The interfacial liquid molecular structure forming spontaneously at the solid liquid interface exists in a wide variety of natural and engineered systems. This microscopic structure plays an important role in governing the macroscopic properties of these materials systems. Particularly in electrochemical systems, this microscopic interfacial structure is crucial for various electrochemical energy storage and conversion processes. However, elucidating the precise molecular-scale liquid structure is challenging because of the limitations of current experimental techniques. In this work, I will discuss how the in-situ interfacial liquid molecular structure can be discerned using our newly developed technique, called electrochemical 3-dimensional atomic force microscopy (EC-3D-AFM). We initially used 3-dimensional atomic force microscopy (3D-AFM) to understand the mechanical properties of a wrinkled graphene system. We can obtain quantitative information about the air-solid interface at the nanoscale. We then extended this technique by performing this entire imaging process inside a liquid, accompanied by electrochemical control, namely, EC-3D-AFM. We used this technique to understand the interfacial structure of the ionic liquid (electrolyte) – graphite (electrode) interface. We further observed a stark reconfiguration of this structure upon the application of surface potential and supplemented our understanding with collaborative molecular dynamics (MD) simulations. We then observed how the interfacial structure looks like when we change the electrode surface from graphite (a material with uniform surface potential) to molybdenum disulfide (MoS2) (a semiconductor with varying surface potential). This led to some interesting findings where we observed a common trend of the reconfiguration of the interfacial structure on both materials’ surfaces, but the absolute values at which this reconfiguration occurs depends on the surface potential of individual MoS2 flakes. Finally, we also used this technique to understand the fundamental interplay between nucleation and growth and solvation structures during an electrodeposition process in a model system mimicking the anode half-cell of a lithium-ion battery.

Graduation Semester

2024-05

Type of Resource

Thesis

Copyright and License Information

Copyright 2024 Kaustubh Panse

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