Faculty Directory

Lee, Sang Bok

Lee, Sang Bok

Associate Professor, Chemistry and Biochemistry
Director, MD Nanocenter
Materials Science and Engineering
Chemical and Biomolecular Engineering
0107 Chemistry Building

EDUCATION

Ph.D., Seoul National University, 1997

Recently, supercapacitors have received growing interest as an complementary energy-storage device and a small scale power system for mobile electronics with the rapid advance of high-performance electronic devices.

Conductive polymers and transition metal oxides are promising materials for the redox supercapacitor because they can be readily converted between oxidized and reduced states by the switch of the applied potential. This conversion process involves charging/discharging (or doping/dedoping) of counter-ions to keep electro-neutrality in the materials, which is a fundamental character for a capacitor. Because the mass transfer of counter ions is necessary, however, this charging/discharging is too slow to provide required high power. This results in an inefficient utilization of the electroactive material, that is, loss of usable energy.

The hollow nanotubular structures can provide a solution for fast charge/discharge with their intrinsic structural characteristics. The thin nature of the nanotube wall enables the rapid redox process of conductive polymer by providing short diffusion distance to the counter-ions in the nanotubes (as well as in bulk solution). Furthermore, long nanotubes can provide high mass-loading for enough energy density.

We investigate the supercapacitive electrochemical properties of the nanotube arrays with various materials such as conductive polymer (e.g. PEDOT and polypyrole) and metal oxide (e.g. MnO2 and RuO2). The micron-long, thin-walled nanotubular structures will allow the full usage of deposited materials even at fast charge/discharge rate and enable us to accomplish a supercapacitor with high power density and high energy density. The nanostructures are synthesized by electrochemical method rather than chemical one to provide higher conductivity.

Electrochemical synthesis of nanotube-structured materials for ultrafast electrochromics, supercapacitors, and solar cells; magnetic nanotubes for targeted drug delivery and chemical/biochemical separation; shape-coded nanotubes for dispersible nanosensors; properties of pseudo-1-dimensional silica nanotubes; chemical and biochemical sensors.

Gary Rubloff named Distinguished University Professor

Rubloff receives highest academic honor conferred by the University of Maryland.

Experts available for comment on upcoming Nobels

Lithium-ion batteries and nanowires are candidates for chemistry and physics prizes; UMD scientists can explain importance

Mesoscale Science Research Highlighted on Materials Journal Cover

Rubloff and Lee show new direction in electrical energy storage

New Battery Demonstrates “Sweet Spot” of Electrolyte Thickness and Composition

Atom-scale synthesis makes highly conductive LiPON for solid-state battery

Food Safety, Energy Storage & Video Authentication Inventions Honored at Awards Ceremony

Three Clark School innovations win UMD Invention of the Year Awards

A Billion Holes Can Make a Battery

Battery inside a nanopore has commercial potential

Department of Energy renews NEES EFRC for four years

The center develops highly ordered nanostructures that offer a unique way of looking at the science of energy storage.

Rubloff, Ghodssi featured in JVST-A special issue

The Journal of Vacuum Science & Technology A is celebrating the 60th anniversary of the American Vacuum Society.

Spinning Engineered Silk Into Tiny Designs—With A Microscope

Atomic force microscopy to guide formation of polymer threads.

Rubloff Team Invention of the Year Could Revolutionize Electronics

Electrostatic nanocapacitors are high-powered, easy to manufacture.

Espy-Wilson, Rubloff Are Top UM Inventors

Speech enhancing algorithm, high-density energy storage cells named best of '09.

UMERC/Nanocenter Team Named "Energy Frontier" Center

Cross-campus team works to improves electrical storage technologies.

NanoCenter Improves Energy Storage Options

Maryland NanoCenter researchers create new device to store electrical energy.

ResearchFest 2009 Winners Announced

Nargund, Thomas, and Dowling presentations come out on top.

Materials and Interface Nanotechnology Laboratory Opens

Research will include work on nanoparticles, nanowires.

MSE Graduate Student Wins Best Poster Award

Israel Perez honored at MEMS Alliance Special Topics Symposium.