Faculty Directory

Lee, Sang Bok

Lee, Sang Bok

Associate Professor, Chemistry and Biochemistry
Director, MD Nanocenter
Materials Science and Engineering
Chemical and Biomolecular Engineering
Maryland Energy Innovation Institute
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.

UMD Start-Up Ionic Devices Wins Microbattery Design Prize

One of Eight Awarded by US Department of Energy

ARL to Fund $30M in Equipment Innovations for Service Members

UMD announces with the U.S. Army Research Lab agreements in additive manufacturing and battery research.

UMD Research Team Advances the Battery Revolution

Solid state energy storage research receives $2.25M in DOE funding.

MEI2 leads U.S. side of $18.4M U.S.-Israel Energy Center focused on Energy Storage

Project will Develop Lithium and Sodium Metal Solid State Batteries for Advanced Energy Storage Applications

NEES in DOE EFRC Newsletter

NEES grad student Sahadeo writes about ALD-enabled solid-state batteries

DOE Newsletter features NEES science and science communication

NEES electron microscopy featured; Chemistry grad student pens article

A New Dimension for Batteries

Nanostructured battery is safe, manufacturing-compatible, and delivers much higher power at high energy

EFRC NEES-2 meeting poster contest winners

Accomplishments meeting announces poster awards

Students Showcase Outstanding Basic, Applied and Innovative Energy Research

Poster session at NEES meeting highlights nanostructures in energy research

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

Thin coatings controlled at atomic scale protect high performance lithium anodes

Anodes with layer of alumina resist corrosion and cycle well

Members of NEES Gather for 2015 Spring Accomplishment Meeting

Poster session, in-depth discussions, presentations.... and hiking

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

NanoCenter Members Present Papers at Upcoming APS Meeting in Baltimore

Largest physics meeting hosts more than twenty NanoCenter presentations  

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

DOE to award $14M for nanotech storage technology crucial to renewable energy success.

NanoCenter Improves Energy Storage Options

Maryland NanoCenter researchers create new device to store electrical energy.