김동원 교수

The enhanced stability of lithium metal is vital to the development of high energy density lithium batteries due to its higher specific capacity and low redox potential. Herein, we demonstrate that nitrogen and sulfur codoped graphene (NSG) nanosheets coated on a polyethylene separator stabilized the lithium electrode in lithium metal batteries by effectively suppressing dendrite growth and maintaining a uniform ionic flux on the metal surface. The ultrathin layer of NSG nanosheets also improved

LiNi0.6Co0.2Mn0.2O2 cathode materials were surface-modified by coating with a dual conductive poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol) (PEDOT-co-PEG) copolymer, and their resulting electrochemical properties were investigated. The surface-modified LiNi0.6Co0.2Mn0.2O2 cathode material exhibited a high discharge capacity and good high rate performance due to enhanced transport of Li(+) ions as well as electrons. The presence of a protective conducting polymer layer formed on the c

We demonstrate the effectiveness of dual-layer coating of cathode active materials for improving the cycling performance and thermal stability of lithium-ion cells. Layered nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material was synthesized and double-layer coated with alumina nanoparticles and poly(3,4-ethylenedioxythiophene)-co-poly(ethylene glycol). The lithium-ion cells assembled with a graphite negative electrode and a double-layer-coated LiNi0.6Co0.2Mn0.2O2 positive electrode exhibited high d

Trapping lithium polysulfides formed in the sulfur positive electrode of lithium-sulfur batteries is one of the promising approaches to overcome the issues related to polysulfide dissolution. In this work, we demonstrate that intrinsically hydrophilic magnesium oxide (MgO) nanoparticles having surface hydroxyl groups can be used as effective additives to trap lithium polysulfides in the positive electrode. MgO nanoparticles were uniformly distributed on the surface of the active sulfur, and the

Abstract Novel composite gel polymer electrolytes exhibiting high ionic conductivity and good mechanical stability are prepared, and their electrochemical properties are characterized. As lithium ion sources of a single ion conductor, the core‐shell structured SiO 2 (Li + ) nanoparticles with uniform spherical shape are synthesized and used as functional fillers in the composite gel polymer electrolytes. By using the composite gel polymer electrolytes, the lithium powder polymer batteries compos

All-solid-state lithium batteries (ASSLBs) are considered promising alternatives to current lithium-ion batteries as their use poses less of a safety risk. However, the fabrication of composite cathodes by the conventional slurry (wet) process presents technical challenges, such as limited stability of sulfide electrolytes against organic solvents and the increase of ionic resistance due to the use of insulating polymer binder. Herein, we develop a composite cathode fabricated using a solvent-fr

Uniform co-doping of nitrogen and sulfur on graphene effectively catalyzes the triiodide reduction, resulting in high conversion efficiency of DSSCs.

In this study, we have developed a SiGe dot floating-gate flash memory with high-K dielectric (HfO/sub 2/) tunneling oxide. Using SiGe dots and HfO/sub 2/ tunneling oxide, a low program/erase voltage can be achieved, along with good endurance and charge retention characteristics as compared to the SiGe dots with a SiO/sub 2/ tunneling oxide. We have also examined the impact of Ge concentration in the SiGe dots on charge retention time. This demonstrates that the SiGe dots with HfO/sub 2/ tunneli

Cobalt chrome molybdenum alloy is considered as one of the advanced materials which is widely gaining popularity in various engineering and medical applications. However, it is categorized as difficult to machine material due to its unique combination of properties which include high strength, toughness, wear resistance and low thermal conductivity. These properties tend to hinder the machinability of this alloy which results in rapid tool wear and shorter tool life. This paper presents a genera