Publications by authors named "Hyung Kyun Yu"

9 Publications

  • Page 1 of 1

Correction: Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole.

Chem Commun (Camb) 2015 Feb;51(16):3474

School of Chemical Engineering, College of Engineering, Hanyang University, Seoul 133-791, Korea.

Correction for 'Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole' by Moon Joo Lee et al., Chem. Commun., 2015, 51, 2068-2071.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c5cc90064fDOI Listing
February 2015

Highly lithium-ion conductive battery separators from thermally rearranged polybenzoxazole.

Chem Commun (Camb) 2015 Feb;51(11):2068-71

School of Chemical Engineering, College of Engineering, Hanyang University, Seoul 133-791, Korea.

High power density lithium ion battery (HLIB) separators were fabricated for the first time from thermally rearranged poly(benzoxazole-co-imide) (TR-PBOI) nanofibrous membranes coated with TR-PBOI nanoparticles, which show distinct thermal and dimensional stabilities as well as excellent cycle retention and rate capability.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1039/c4cc09411eDOI Listing
February 2015

Inverse opal-inspired, nanoscaffold battery separators: a new membrane opportunity for high-performance energy storage systems.

Nano Lett 2014 Aug 3;14(8):4438-48. Epub 2014 Jul 3.

School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST) , Ulsan, 689-798, Korea.

The facilitation of ion/electron transport, along with ever-increasing demand for high-energy density, is a key to boosting the development of energy storage systems such as lithium-ion batteries. Among major battery components, separator membranes have not been the center of attention compared to other electrochemically active materials, despite their important roles in allowing ionic flow and preventing electrical contact between electrodes. Here, we present a new class of battery separator based on inverse opal-inspired, seamless nanoscaffold structure ("IO separator"), as an unprecedented membrane opportunity to enable remarkable advances in cell performance far beyond those accessible with conventional battery separators. The IO separator is easily fabricated through one-pot, evaporation-induced self-assembly of colloidal silica nanoparticles in the presence of ultraviolet (UV)-curable triacrylate monomer inside a nonwoven substrate, followed by UV-cross-linking and selective removal of the silica nanoparticle superlattices. The precisely ordered/well-reticulated nanoporous structure of IO separator allows significant improvement in ion transfer toward electrodes. The IO separator-driven facilitation of the ion transport phenomena is expected to play a critical role in the realization of high-performance batteries (in particular, under harsh conditions such as high-mass-loading electrodes, fast charging/discharging, and highly polar liquid electrolyte). Moreover, the IO separator enables the movement of the Ragone plot curves to a more desirable position representing high-energy/high-power density, without tailoring other battery materials and configurations. This study provides a new perspective on battery separators: a paradigm shift from plain porous films to pseudoelectrochemically active nanomembranes that can influence the charge/discharge reaction.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/nl5014037DOI Listing
August 2014

Measurement and analysis of adhesion property of lithium-ion battery electrodes with SAICAS.

ACS Appl Mater Interfaces 2014 Jan 13;6(1):526-31. Epub 2013 Dec 13.

Department of Chemical and Biological Engineering, Hanbat National University , Deokmyoung-dong, Yuseong-gu, Daejeon 305-719, Republic of Korea.

The adhesion strength of lithium-ion battery (LIB) electrodes consisting of active material, a nanosized electric conductor, and a polymeric binder is measured with a new analysis tool, called the Surface and Interfacial Cutting Analysis System (SAICAS). Compared to the conventional peel test with the same electrode, SAICAS gives higher adhesion strength owing to its elaborate cutting-based measurement system. In addition, the effects on the adhesion property of the polymeric binder type and content, electrode density, and measuring point are also investigated to determine whether SAICAS provides reliable results. The findings confirm SAICAS as an effective and promising tool to measure and analyze the adhesion properties of LIB electrodes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/am404580fDOI Listing
January 2014

Cable-type flexible lithium ion battery based on hollow multi-helix electrodes.

Adv Mater 2012 Oct 7;24(38):5192-7, 5145. Epub 2012 Aug 7.

Battery R&D, LG Chem, Ltd., 104-1 Moonji-dong, Yuseong-gu, Daejeon 305-380, Republic of Korea.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/adma.201202196DOI Listing
October 2012

Genesis of anisotropic colloidal particles via protrusion of polystyrene from polyelectrolyte multilayer encapsulation.

J Am Chem Soc 2009 May;131(18):6366-7

Max Planck Institute of Colloids and Interfaces, D-14424 Potsdam, Germany.

Incubation of polyelectrolyte multilayer coated polystyrene particles in a mixture of water and tetrahydrofuran leads to rapid protrusion of the polystyrene through the polyelectrolyte coating and thus to formation of anisotropic particles, which is independent of the polystyrene core size and the polyelectrolyte coating composition.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ja901705fDOI Listing
May 2009

Multi-faceted titanium glycolate and titania structures from room-temperature polyol process.

J Colloid Interface Sci 2007 Dec 27;316(1):175-82. Epub 2007 Jul 27.

National Creative Research Initiative Center for Integrated Optofluidic Systems, Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, South Korea.

Multi-faceted microstructures of titanium glycolate have been produced by room-temperature polyol process in which titanium alkoxide and polymethylene glycol were mixed rigorously and then the mixture was aged to settle down as white precipitate. Depending on types of titanium alkoxides and polymethylene glycols, stirring time, and composition, a variety of polygonal microrods were generated. Unlike unidentified structures produced from polyol process at elevated temperature, the titanium glycolate products obtained at room temperature revealed well-defined rod-like or plate-like structures with polygonal cross sections. Then, as-prepared titanium glycolate microstructures were transformed into higher refractive index titania of anatase or rutile phase by annealing. The characterization of as-prepared and annealed structures was conducted using scanning and transmission electron microscopes, X-ray diffractomer, and thermal analyzer for thermogravimetry and differential scanning calorimetry.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcis.2007.07.043DOI Listing
December 2007

Nanomachining by colloidal lithography.

Small 2006 Apr;2(4):458-75

Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea.

Colloidal lithography is a recently emerging field; the evolution of this simple technique is still in progress. Recent advances in this area have developed a variety of practical routes of colloidal lithography, which have great potential to replace, at least partially, complex and high-cost advanced lithographic techniques. This Review presents the state of the art of colloidal lithography and consists of three main parts, beginning with synthetic routes to monodisperse colloids and their self-assembly with low defect concentrations, which are used as lithographic masks. Then, we will introduce the modification of the colloidal masks using reactive ion etching (RIE), which produces a variety of nanoscopic features and multifaceted particles. Finally, a few prospective applications of colloidal lithography will be discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/smll.200500390DOI Listing
April 2006

Colloidal lithographic nanopatterning via reactive ion etching.

J Am Chem Soc 2004 Jun;126(22):7019-25

Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong, Yuseong-gu, Daejeon 305-701 Korea.

We report here a novel colloidal lithographic approach to the fabrication of nonspherical colloidal particle arrays with a long-range order by selective reactive ion etching (RIE) of multilayered spherical colloidal particles. First, layered colloidal crystals with different crystal structures (or orientations) were self-organized onto substrates. Then, during the RIE, the upper layer in the colloidal multilayer acted as a mask for the lower layer and the resulting anisotropic etching created nonspherical particle arrays and new patterns. The new patterns have shapes that are different from the original as a result of the relative shadowing of the RIE process by the top layer and the lower layers. The shape and size of the particles and patterns were dependent on the crystal orientation relative to the etchant flow, the number of colloidal layers, and the RIE conditions. The various colloidal patterns can be used as masks for two-dimensional (2-D) nanopatterns. In addition, the resulting nonspherical particles can be used as novel building blocks for colloidal photonic crystals.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/ja0319083DOI Listing
June 2004