Engineering Nano-scale Materials and Systems for High-Capacity Lithium and Sodium Ion Anodes
Nanotechnology is a revolutionary area that has remarkably affected electrochemical properties of materials for use as electrodes in lithium-ion batteries, PEM fuel cell catalysts, and supercapacitors. Since the discovery of tin oxide nanocomposites as promising anode materials for lithium-ion batteries by Fuji, there has been burgeoning activities focused at identifying alternate materials to graphite, the current anode material of choice. Several strategies have been researched over the last few years involving identifying new intermetallic anode systems, generation of a nanostructured disordered matrix containing the electrochemically active component upon electrochemical insertion of lithium as well as creation of nanowires and ‘core-shell’ structures.
Our research over the years has been directed at synthesizing nanostructured composites comprising active and inactive phases directly by exploiting novel low-cost synthetic approaches including nanostructured hollow Si nanotubes (h-Si-NT). The electrochemically inactive species comprising transition metal non-oxides, carbon and carbon nanotubes have been selected based on their thermodynamic and electrochemical stability towards lithium. The nanocomposites are fabricated by exploiting mechanochemical-based approaches as well as low temperature liquid injection chemical vapor deposition techniques (CVD). Initial results have shown that the resulting intra-type nanocomposites exhibit stable capacities as high as 1000 mAh/g while novel vertically aligned CNTs containing nanoscale Si clusters to form hybrid heterostructures exhibit impressive capacities as high as ~3000 mAh/g. An intriguing aspect of the work is the Si-CNT interaction that serves to tether the amorphous/nanoscale Si clusters to the underlying CNT which results in the system exhibiting stable reversible capacities. Opportunities and challenges related to synthesis and design of nanostructured materials for next generation Li-ion and extension to Na-ion systems will be presented and discussed.
About the Presenter:
Professor Kumta obtained his Bachelor of Technology in Metallurgical Engineering from the Indian Institute of Technology, Bombay, India in 1984. He then obtained his M.S. and Ph.D. degrees in Materials Science and Engineering from the University of Arizona in 1987 and 1990, respectively. He joined the Materials Science and Engineering Department at Carnegie Mellon University as an Assistant Professor in 1990. He was promoted to Full Professor with tenure in 1999. After serving on the MSE and BME faculty at CMU for 17 years, in 2007, he joined the University of Pittsburgh as the Edward R.
Weidlein Chair Professor in the Swanson School of Engineering and the School of Dental Medicine with appointments in Bioengineering, Chemical and Petroleum Engineering, Mechanical Engineering and Materials Science as well as the Department of Oral Biology. Professor Kumta’s main research interests are in the synthesis, structure and properties of nanostructured materials for a variety of electrochemical systems. He also has interests in biomaterials for biofunctional applications. He is the author and co-author of more than 200 refereed publications and is currently the Editor-in-Chief of Materials Science and Engineering, B, Advanced Functional Solid-State Materials, an International Journal by Elsevier. He is also a Fellow of the American Ceramic Society (ACerS) and the American Institute of Medical and Biological Engineers (AIMBE).