Capacitive Performance of Two-Dimensional Metal Carbides A Thesis Submitted to the Faculty of Drexel University by Maria R. Lukatskaya in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2015 © Copyright 2015 Maria R. Lukatskaya. All Rights Reserved. 3 DEDICATIONS To my beloved husband Andrei and to my mom Luidmila, who have always been my source of constant support, love and motivation to become a better person. 4 ACKNOWLEDGEMENTS I would like to wholeheartedly thank my advisor, Prof. Yury Gogotsi, his positive attitude, respect towards people he works with and excitement about science made my PhD time at Drexel the most enriching. I am very grateful that he had always found time to discuss research, provide guidance, feedback and encouragement, all that despite of how busy his schedule was. He is a continuous source of inspiration, support and encouragement. I equally want to thank my co-advisor, Prof. Michel Barsoum whose inspirational excitement about research, continuous support and encouragement for vocalizing opinion and pursuing new ideas always stimulated me to explore new directions. I feel very lucky to have such great PhD advisors and I am very grateful to both of them for their enthusiasm and confidence in me that helped me to grow so much as scientist and person, taught me too see bigger picture. I would like to thank my committee members: Prof. Patrice Simon, Prof. Steve May, Prof. Ekaterina Pomerantseva and Prof. Gennady Friedman for taking time from their busy schedules to review and evaluate this work, providing feedback and guidance. I would like to thank all members (current and former, from the time of my first internship at Drexel University in 2010) of Drexel Nanomaterials group for their help and support and for making all the years of my PhD such a pleasant experience by establishing friendly, collaborative and creative atmosphere. I want to particularly thank following people with whom I worked closely and who in many ways contributed to this work (and other exciting research activities I was involved in): Dr. Olha Mashtalir, Sankalp Kota, 5 Michael Ghidiu, Dr. Meng-Qiang Zhao, Chang (Evelyn) Ren, Yohan Dall’Agnese, Dr. Michael Naguib, Joseph Halim, Boris Dyatkin, Katie Van Aken, Mohamed Alhabeb, Br. Babak Anasori, Dr. Zheng Ling, Dr. Kevin Cook, Dr. Riju Singhal, Dr. Murat Kurtoglu, Dr. John (Jake) McDonough, Dr. Vadym Mochalin. Especially, I would like to thank Michael Naguib, Olha Mashtalir, Joseph Halim and Boris Dyatkin and for their friendship, support. I also want to thank our collaborators, my interaction with whom was always fruitful and enriching and allowed me to bring understanding of MXenes to the next level. In particular: Dr. Seongmin Bak, Dr. Xiqian Yu and Dr. Xiao‐Qing Yang and at Brookhaven National Laboratory for performing in-situ XAS measurements which allowed to finally understand mechanism of capacitance in MXenes; Dr. Michael Levi, Sergey Sigalov, Netanel Shpigel at Bar-Ilan University for electrochemical quartz crystal microbalance and admittance studies; Dr. Jeremy Come, Dr. Jennifer Black and Dr. Nina Balke at Oak Ridge National Laboratory for in-situ AFM studies; Dr. Encarnacion Raymundo-Piñero at University of Orléans (Orléans, France) for temperature programmed desorption with mass-spectrometry studies of MXenes; Dr. Alexander Sinitskii and Alexey Lipatov at University of Nebraska-Lincoln for electronic properties measurements; Dr. Clare Grey, Michael Hope, Alexander C. Forse, and Kent J. Griffith for NMR measurements. I am especially thankful to Prof. Patrice Simon and Prof. Bruce Dunn for numerous discussions, guidance and who each hosted me during research visits to Université Paul Sabatier (Toulouse, France) and University of California, Los Angeles, respectively. 6 I wanted to thank funding agencies that made it possible to perform this research. The work have been supported by Office of Electricity Delivery and Energy Reliability, Energy Storage Systems Program, through Sandia National Laboratories and as part of the Fluid Interface Reactions, Structures and Transport (FIRST) Center, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, and Office of Basic Energy Sciences. Also, I’m grateful to Partner University Fund (PUF) for supporting my research trip to Prof. Simon’s laboratory at Université Paul Sabatier, Toulouse, France. Also, separate thanks to the Office of International Programs at Drexel University for the financial support towards traveling to international conferences. I am also very grateful to the Drexel Nanomaterials Institute staff, particularly Wendy Thurman and Danielle Tadros Kopicko, for their great help, support, and patience and for always being positive and welcoming. I also want to express special ‘thank you’ to the staff members of Materials Science and Engineering Department, particularly Keiko Nakazawa, Yenneeka Long, and Sarit Kunz, for their indispensable administrative support. Finally, I want to thank my family, in particular my mom Luidmila, who 12 years ago made me interested in chemistry, always supported and believed in me. And, my beloved husband Andrei for his love, unconditional support, humor and encouragement. 7 TABLE OF CONTENTS DEDICATIONS .................................................................................................................. 3 ACKNOWLEDGEMENTS ................................................................................................ 4 TABLE OF CONTENTS .................................................................................................... 7 LIST OF TABLES ............................................................................................................ 11 LIST OF FIGURES .......................................................................................................... 12 LIST OF ABBREVIATIONS ........................................................................................... 21 ABSTRACT ...................................................................................................................... 23 CHAPTER 1: INTRODUCTION ............................................................................... 25 CHAPTER 2: BACKGROUND AND LITERATURE SURVEY ............................. 27 2.1 Faradaic and capacitive energy storage ...............................................................27 2.2 Electrode nanostructuring and 2D materials .......................................................32 2.3 MXenes-a new family of the 2D layered materials.............................................35 2.4 Intercalation and delamination of MXenes .........................................................37 2.5 MXenes as electrode materials for Li-ion batteries ............................................38 CHAPTER 3: MATERIALS AND METHODS ........................................................ 41 3.1 MXene synthesis .................................................................................................41 3.1.1 Synthesis of Ti3AlC2 ................................................................................... 41 3.1.2 Synthesis of multilayer Ti3C2Tx MXene (HF method) ............................... 41 3.1.3 Synthesis of Ti3C2Tx MXene clay (LiF+HCl method) ............................... 42 3.1.4 Synthesis of multilayered Nb2CTx .............................................................. 42 3.2 Chemical modification treatment of MXenes .....................................................43 3.2.1 Intercalation of multilayered Ti3C2Tx ......................................................... 43 8 3.2.2 Surface modification ................................................................................... 44 3.2.3 Delamination of Ti3C2Tx ............................................................................. 44 3.2.4 Delamination of Nb2CTx ............................................................................. 45 3.3 Electrode preparation ..........................................................................................46 3.3.1 Electrode film preparation from the multilayer Ti3C2Tx powder ................ 46 3.3.2 “Paper” electrode preparation ..................................................................... 46 3.3.3 Paper electrodes with CNTs........................................................................ 46 3.3.4 Electrode preparation from MXene clay (LiF+HCL method) .................... 47 3.3.5 Activated carbon (AC) counter electrodes .................................................. 48 3.4 General material characterization methods .........................................................48 3.5 Electrochemical measurements ...........................................................................49 3.5.1 Electrochemical set-up ................................................................................ 49 3.5.2 Electrolytes ................................................................................................. 50 3.5.3 Electrochemical testing ............................................................................... 52 3.6 In-situ electrochemical characterization ..............................................................53 3.6.1 In-situ electrochemical XRD ...................................................................... 53 3.6.2 In-situ X-ray Absorption Spectroscopy (XAS) ........................................... 54 3.6.3 In-situ Atomic Force Microscopy ..............................................................