ELECTRODEPOSITION OF MATERIALS FROM NOVEL SOLVENTS by WILLIAM DONALD SIDES QIANG HUANG, COMMITTEE CHAIR AMANDA KOH DAWEN LI QING PENG JOHN WILLIAM VAN ZEE A DISSERTATION Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemical and Biological Engineering in the Graduate School of The University of Alabama TUSCALOOSA, ALABAMA 2019 Copyright William Donald Sides 2019 ALL RIGHTS RESERVED ABSTRACT The electrodeposition of metals and alloys is explored with a focus on solvents and additives capable of reducing or eliminating hydrogen evolution while operating at highly cathodic potentials. The nucleation and growth behavior of binary codepositing systems are modelled in Chapter 2. Deep eutectic solvents based on choline chloride and urea are demonstrated to be capable of electrodepositing metallic manganese for the first time in Chapter 3. Chapter 4 describes the first time manganese has been incorporated into an electrodeposited magnetic iron-group alloy. Water-in-salt electrolytes are applied to the electrodeposition of metals in Chapters 5 and 6. These electrolytes are shown to suppress the proton reduction reaction and subsequent hydrogen evolution in aqueous systems. The tetrabutylammonium ion is also shown to be capable of suppression of proton reduction. The origins of this suppression are examined in Chapter 6, and it is determined that the additive adsorbs onto the electrode surface, blocking proton access. The suppressing behaviors of tetrabutylammonium and water-in-salt electrolytes are combined to achieve significant suppression of proton reduction and the ability to electrodeposit metals at highly negative cathodic potentials. Chapter 6 describes the use of these solvents to electrodeposit ruthenium for interconnect applications. The origin of enhanced superconductivity in rhenium electrodeposited from water- in-salt electrolytes is explored in Chapter 5. A disordered atomic structure is found to be highly correlated with enhanced superconductivity. ii LIST OF ABBREVIATIONS AND SYMBOLS 퐴 Nucleation rate per active site AFM Atomic force microscopy 퐶0 Bulk concentration of active species 푐 Concentration ChCl Choline chloride CI(G)S Copper indium (gallium) selenide CV Cyclic voltammogram CVD Chemical vapor deposition 퐷 Diffusion coefficient 퐷 Grain size DA Single donor, single acceptor of hydrogen bonds DAA Single donor, double acceptor of hydrogen bonds DDA Double donor, single acceptor of hydrogen bonds DDAA Double donor, double acceptor of hydrogen bonds DES Deep eutectic solvent 퐸 Electric potential 퐸퐴 Activation energy EDS Energy dispersive x-ray spectroscopy EIS Electrochemical impedance spectroscopy EQCM Electrochemical quartz crystal microbalance iii 퐹 Faraday’s constant FM Frank-van der Merwe 퐻푐 Magnetic coercivity HBD Hydrogen bond donor HER Hydrogen evolution reaction 푖 Current density 퐾 Crystallite shape factor 푘푐푎푝 Capacitive current density constant 푀 Molar mass 푀푠 Saturation magnetization M-H Magnetic field strength versus magnetization 푁0 Number density per active site PPMS Physical property measurement system 푅 Gas constant RDE Rotating disk electrode RMS Root mean square SCE Saturated calomel reference electrode SEM Scanning electron microscopy SIMS Secondary ion mass spectroscopy SK Stranski-Krastanov STEM Scanning transmission electron microscopy 푇 Temperature 푇퐶 Critical temperature of superconductivity iv 푡 Time TBA Tetrabutylammonium TEM Transmission electron microscopy U Urea UPD Underpotential deposition VSM Vibrating sample magnetometry VW Volmer-Weber WiSE Water-in-salt electrolyte XRD X-ray diffraction XRF X-ray fluorescence 푧 Number of electrons transferred per molecule reduced 훼 Dimensionless nucleation parameter 훽 Full peak width at half maximum ∆퐺푓 Standard Gibbs free energy of formation 휃 Diffraction angle 휆 Wavelength 휇0 Vacuum permeability 휈 Kinematic viscosity 휌 Density σ Standard deviation 휏푐푎푝 Capacitive charging time constant 휔 Angular rotation rate v ACKNOWLEDGEMENTS I would like to thank everyone who supported and guided me throughout my time at The University of Alabama. My PhD advisor Qiang Huang provided me with invaluable guidance both in research and in life. I truly appreciate his feedback on manuscripts, his backing of my academic travel and networking opportunities, and his tremendous support of my professional development. I would like to acknowledge my committee members Amanda Koh, Dawen Li, Qing Peng, and John William Van Zee, for their invaluable guidance and suggestions. I wish to recognize Shuvodeep De, Yang Hu, Joseph Ortenero, Tim Brusuelas, William Freeman, Nikolas Kassouf, Tyler Lyons, Dan Mantoni, Christopher Menas, Ryan Morelock, Keaton Ramsey, John White, and all other members of my research group for their help. I would also like to thank my colleagues in the graduate school Matthew Confer, Al Gilani, Haoming Yan, and Xiaozhou Yu for encouragement and advice along the way. Of course, I would not be where I am without the unwavering support of my family, for which I am forever thankful. Finally, I need to thank all faculty, staff, and students of the Department of Chemical and Biological Engineering at The University of Alabama, as well as the Central Analytical Facility, the Center for Materials for Information Technology, the Chemistry Glass Shop, and the College of Engineering Machine Shop. Financial support by the National Science Foundation, the Graduate Council, and the Research Grant Council at The University of Alabama is greatly appreciated. vi CONTENTS ABSTRACT ............................................................................................................................................................... ii LIST OF ABBREVIATIONS AND SYMBOLS .................................................................................................. iii ACKNOWLEDGEMENTS .................................................................................................................................... vi LIST OF TABLES.................................................................................................................................................... xi LIST OF FIGURES ................................................................................................................................................. xii CHAPTER 1. INTRODUCTION ........................................................................................................................... 1 Motivation ....................................................................................................................................................... 1 Electrochemical Methods .......................................................................................................................... 5 References ....................................................................................................................................................... 7 CHAPTER 2. ELECTROCHEMICAL NUCLEATION AND GROWTH OF ANTIMONY TELLURIDE BINARY COMPOUND ON GOLD SUBSTRATE ................................................................. 10 Summary ....................................................................................................................................................... 10 Introduction ................................................................................................................................................. 10 Experimental ............................................................................................................................................... 12 Results and Discussion ............................................................................................................................ 13 Voltammetric studies ...................................................................................................................... 13 Chronoamperometry studies ....................................................................................................... 17 Nucleation site characterization ................................................................................................. 24 Conclusion .................................................................................................................................................... 25 Acknowledgements .................................................................................................................................. 26 References .................................................................................................................................................... 26 vii Supplementary Information .................................................................................................................. 30 CHAPTER 3. ELECTRODEPOSITION OF MANGANESE THIN FILMS ON A ROTATING DISK ELECTRODE FROM CHOLINE CHLORIDE/UREA BASED IONIC LIQUIDS .................................... 32 Summary ....................................................................................................................................................... 32 Introduction ................................................................................................................................................. 32 Experimental ............................................................................................................................................... 34 Results and Discussion ...........................................................................................................................