Dean's Speaker Series:Design of Materials for Advanced Energy Storage...

Guest: Cengiz Sinan Özkan

Date/ Time: June 6,2022 18:30

Title:"Design of Materials for Advanced Energy Storage

I enthusiastically invite you to join us by using the following link:

Zoom link: https://sabanciuniv.zoom.us/j/6450818950

Abstract:The global electrochemical energy storage market ranging from electric vehicles and personal electronics to physical grid storage and defense applications demands the development of new classes of materials for fabricating high performance batteries and supercapacitors. I will describe innovative approaches for the design and synthesis of nanostructured materials towards enhanced reversible capacity; superior rate performance and cycling stability; superior gravimetric capacitance; and enhanced energy density and power density. Hierarchical three-dimensional (3D) graphene-carbon nanotube hybrid materials called pillared graphene nanostructures (PGN) grown by chemical vapor deposition possess ultra large surface area, tunability, mechanical durability and high conductivity which are appealing to diverse energy storage systems. Integration of nanostructured pseudocapacitive metal oxides to such 3D hierarchical templates provides superior electrochemical performance. Among the high-performance capacitor systems developed includes MGM (graphene-MWNT-Manganese oxide) and RGM (graphene-MWNT-Ruthenium oxide) hybrid systems. High specific/areal capacitance and extended operational voltage window provides an exceptionally high energy density and power density. Similar three-dimensional templates are transformed into cone-shaped carbon nanotube clusters decorated with amorphous silicon for lithium ion battery anodes (SCCC), by depositing amorphous silicon onto the mesoporous nano-carbon templates via magnetron sputtering. The seamless connection between silicon decorated CNT cones and the graphene substrate facilitates charge transfer and provides a binder-free technique for preparing lithium ion battery anodes. Lithium ion batteries based on the SCCC architecture demonstrated ultra-fast charging, high reversible capacity and excellent cycling stability. Mildly reduced graphene oxide (mrGO) and silica coated Sulfur particles (SCSP) have been developed as new generation cathode materials, forming the basis for Li–S batteries. During cycling, SCSPs fracture and release active material, and mrGO helps to contain the ruptured particles, thereby reducing the polysulfide shuttling effects and improving the cycling stability.

Biography: Cengiz Ozkan received his Ph.D. degree in Materials Science and Engineering at Stanford University in 1997. He made pioneering advancements in the fields of energy storage, nanoelectronics; 2D materials including graphene, biochemical sensors; and nanopatterning for beyond CMOS. His group developed a new generation of energy storage materials including 3D graphene; silicon nanofiber fabrics; encapsulated sulfur materials; and atomically thin 2D materials for nanoelectronics. He has been a member of several prestigious centers including the SRC STARnet Center for Spintronic Materials, Interfaces and Novel Architectures and the SRC MARCO Center for Functional Engineered Nano Architectonics. Dr. Ozkan has over 700 technical publications including journal articles, proceedings, abstracts, edited books, book chapters and invention disclosures, and over 40 US and foreign patents granted. He is a Member of the National Academy of Inventors (NAI), a Fellow of the Materials Research Society (MRS), and received a number of awards including the William Johnson Founders Award, SRC Inventors Award, European Advanced Energy materials Award, and John J. Guarrera Engineering Educator of the Year Award. His research received significant media attention in many news outlets including the Wall Street Journal, Forbes, Discovery Channel, Physics Today, Popular Science, and more. He organized and chaired nearly 40 conferences worldwide, and had been elected a Global Meeting Chair for the Fall 2021 Meeting of the MRS in Boston, MA.