Bunger-Henry 380 and Virtually via Teams
Meeting ID: 246 109 813 082
Passcode: qPLzL8
Committee
- Prof. Matthew McDowell - ME/MSE (Advisor)
- Prof. Faisal Alamgir - MSE
- Prof. Michael Filler - ChBE
- Prof. Josh Kacher - MSE
- Prof. Meilin Liu - MSE
Abstract
Controlling the crystal structure and morphology of electrodeposited metals is critical for energy storage systems and for making electrical contact to electronic devices. One way to modify the electrodeposition of metals is by using two-dimensional (2D) materials such as graphene, but the impact of 2D interlayers on electrodeposition processes is not well understood. It is expected that electrodeposition could be influenced by the underlying substrate through “remote epitaxy,” where the electronic interactions from the substrate through a thin 2D material can influence growth. However, remote epitaxy has only been explored in the context of physical vapor deposition in high-vacuum environments. The goal of this dissertation is to understand how remote epitaxy effects are balanced with other possible growth behaviors during electrodeposition of a variety of different metals.
Electrodeposition of metals on monolayer graphene is investigated first. Electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) are used to investigate the crystallography and morphology of the deposited materials. The crystallographic orientation of the underlying metal grains beneath the graphene layer are found to strongly influence the orientation of electrodeposited copper and zinc, which is evidence for remote epitaxy. Graphene of multiple thicknesses, ranging from one layer to three layers and beyond, is also used to understand how graphene layer thickness affects remote epitaxy. It is found that remote epitaxy influences electrochemical growth behavior for zinc and copper when using both one and two-layer graphene thicknesses, but for thicker graphene, the influence of remote epitaxy wanes due to the further distance from the substrate. Density functional theory (DFT) modeling shows that electronic interactions between the substrate and electrochemically deposited material are responsible for this behavior. Finally, metal electrodeposition on a different 2D material, hexagonal boron nitride (h-BN), is carried out. h-BN is a 2D material that shares a crystal structure and similar lattice parameters to graphene but is electrically insulating. We find that electrodeposition on h-BN produces faceted Cu particle growth in contrast to larger continuous islands on graphene, as well as higher nucleation overpotentials than deposition on graphene at the same current densities. Overall, this work has revealed that 2D materials modify the electrochemistry of electrodeposition and the orientation of electrodeposited metals through complex interactions between substrate, 2D material, and deposit.