Committee Members:  

Prof. Matthew McDowell, Advisor, MSE  

Prof. Faisal Alamgir, MSE  

Prof. Michael Filler, ChBE  

Prof. Josh Kacher, MSE  

Prof. Meilin Liu, MSE  

Understanding Atomic Interactions through Layered Materials during Metal Electrodeposition

Abstract:

 Controlling the crystal structure and morphology of electrodeposited metals is critical for energy storage systems and contacts to electronic devices. One way to modify the electrodeposition of metals is by using 2D materials such as graphene, but the impact of 2D interlayers on electrodeposition processes is not fully understood. In this dissertation, we investigate the electrodeposition of metals like Zn and Cu onto substrates coated with 2D materials, such as graphene.

Electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) will be used to study how the crystallographic orientation of the underlying metal grains within a substrate impacts the orientation of electrodeposits through layers of graphene with different layer thickness and structural characteristics. It is expected that electrodeposits will be influenced by the underlying substrate through remote epitaxy, where the electronic interactions through 2D material can influence growth. The graphene is also expected to play an important role in maintaining oxide-free metal surfaces to enable epitaxial and electronic interactions from the underlying substrate. Metal electrodeposition can be beneficially controlled through remote epitaxy, potentially extending to other metal systems to prevent unwanted electrodeposition growth morphologies such as dendrites. The goal of this project is to understand how remote epitaxy effects are balanced with other growth behavior during electrodeposition using electrochemistry and electron microscopy.

In this dissertation we will first electrodeposit metals on a monolayer of graphene and characterize their orientation and the electrochemical behavior of the system to understand the electronic interactions that occur when metals are electrodeposited on a 2D material. Then, graphene of multiple thicknesses ranging from one layer to 6-8 layers will be used as a substrate for metal deposition. It is expected that the electronic interactions that govern remote epitaxy and possibly other electronic interactions through graphene will change with varying distance between the underlying substrate and electrolyte. We will perform electrodeposition experiments and electrochemical analysis in conjunction with transmission electron microscopy imaging to understand how electrodeposition behavior transitions from remote epitaxy to deposition on bulk graphite as graphene layer number increases. Finally, in this work we will study how solid-state and liquid-state deposition on 2D materials are different. Because a solid-electrolyte interphase (SEI) layer is not expected to form on the working electrode of a solid-state cell, we will be able to compare the electronic interactions through materials like graphene on metals with unstable electrolytes like Li or Na. Liquid electrolytes completely wet the electrode surface, while solid electrolytes require direct contact with the electrode surface for deposition, which is expected to impact the electronic interactions through 2D materials like graphene at the working electrode.