Enhanced performance of Li-S battery by employing the porous carbon-polymer-sulfur composite as cathode material

배준원,손희상 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

In this presentation, pyrolyzed porous spherical composites of polyacrylonitrile-Ketjenblack carbon and sulfur (pPAN-KB/S) with a high sulfur content (ca. 72%) and enhanced conductivity and porosity (pore volume: 1.42 ㎤/g; BET surface area: 727 ㎡/g) were prepared by an aerosol-assisted process and applied as cathode for lithium-sulfur batteries. Electrochemical tests showed that the pPAN-KB/S composite exhibited a high capacity of 866 mAh/g (based on sulfur) after 100 cycles at 0.5C (1C=1.68 A/g) and a good rate performance at high current density (431 mAh/g at 5C). In addition, a pPAN-KB/S composite electrode with high sulfur loading (ca. 4.4 mg-S/㎠) exhibited impressive electrochemical performance with a reversible capacity of 513 mAh/g and 576 mAh/㎤ (based on sulfur) and a coulombic efficiency >99% after 100 cycles at 0.5C.

Electrohydrodynamic Instabilities of Polymer/Nanoparticle Thin Films

배준원,Thomas P Russell 한국고분자학회 2008 한국고분자학회 학술대회 연구논문 초록집 Vol.33 No.1

Microcapsule embedded self-healing membranes for water purification

배준원,박선주,이지연,박철순,정유림,권오석,이창수 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

A Pathway to Microdomain Alignment in Block Copolymer/Nanoparticle Thin Films under Electric Field

배준원 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.9

The control over microstructure in block copolymer thin films using external electric fields has become an interesting research topic. In this article, the effect of nanoparticle on the microdomain alignments in block copolymer (polystyrene-b-poly(2-vinylpyridine)/nanoparticle (Au) thin films under electric fields has been examined with transmission electron microscopy. The homogeneous dispersion of Au nanoparticles into the block copolymer matrix was achieved by surface modification of nanoparticles with compatible ligands. Compared with the phenomenon seen in the pristine block copolymer thin films, a peculiar alignment behavior was observed in the block copolymer/nanoparticle hybrid thin films under electric fields. In addition, the different pathways observed in the pristine and nanoparticle incorporated block copolymer thin films were also monitored as a function of exposure time. This work can provide the fundamental information for understanding microdomain alignment in block copolymer/nanoparticle thin films under external electric fields.

Fabrication of Carbon Microcapsules Containing Silicon Nanoparticles-Carbon Nanotubes Nanocomposite for Anode in Lithium Ion Battery

배준원,박종남 대한화학회 2012 Bulletin of the Korean Chemical Society Vol.33 No.9

Carbon microcapsules containing silicon nanoparticles (Si NPs)-carbon nanotubes (CNTs) nanocomposite (Si-CNT@C) have been fabricated by a two step polymerization method. Silicon nanoparticles-carbon nanotubes (Si-CNT) nanohybrids were prepared with a wet-type beadsmill method. A polymer, which is easily removable by a thermal treatment (intermediate polymer) was polymerized on the outer surfaces of Si-CNT nanocomposites. Subsequently, another polymer, which can be carbonized by thermal heating (carbon precursor polymer) was incorporated onto the surfaces of pre-existing polymer layer. In this way, polymer precursor spheres containing Si-CNT nanohybrids were produced using a two step polymerization. The intermediate polymer must disappear during carbonization resulting in the formation of an internal free space. The carbon precursor polymer should transform to carbon shell to encapsulate remaining Si-CNT nanocomposites. Therefore, hollow carbon microcapsules containing Si-CNT nanocomposites could be obtained (Si-CNT@C). The successful fabrication was confirmed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). These final materials were employed for anode performance improvement in lithium ion battery. The cyclic performances of these Si-CNT@C microcapsules were measured with a lithium battery half cell tests.

An elaborate sensor system based on conducting polymer-oligosaccharides in hydrogel and the formation of inclusion complexes

배준원,Yunjung Hwang,Sung-Hoon Park,박선주,Jiyeon Lee,Hye Jun Kim,Ayeon Jang,Soyeon Park,Oh Seok Kwon 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.90 No.-

In this study, electrically conductive materials composed of carboxylated polypyrrole (PPy(COOH)) andnontoxic oligosaccharide molecules (cyclodextrin, CD) were prepared and incorporated intobiocompatible hydrogels for use as versatile sensors. The major component, carboxylated polypyrrolenanotubes (PPy(COOH) NTs) were fabricated using microemulsion polymerization and a critical sensingmedium CD molecule was introduced via a simple surface engineering method. The resulting PPy(COOH)-CD NT hybrid complexes were incorporated into a hydrogel matrix for biocompatibleapplications. Consequently, a convenient sensor geometry was constructed by mounting the hydrogelon a gold micropattern for the detection of toxic substances. The feasibility of the produced sensor systemwas demonstrated, and the sensor performance was measured extensively using electrical measure-ments. It was found that the sensor could detect a model compound (methyl paraben, MPRB) atconcentration as low as 1 nM. This study provides useful information for future research activities inrelevantfields.

Tailored hydrogels for biosensor applications

배준원,Jongnam Park,Seong-Soo Kim,조하나,Hye Jun Kim,Soyeon Park,신동식 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.89 No.-

To date, hydrogels have gained attraction due to their inherent advantages such as wide selection ofprecursors and additives, low toxicity, easy shape control, and biological compatibility. Therefore,extensive studies are being conducted for their application in diversefields. In this review, recentimpressive studies on the use of tailored hydrogel materials for biosensor applications have beensummarized. As the hydrogel precursors and the sensing mechanisms are wide and extensive, we havesummarized chemical/biological sensors depending on the hydrogel precursors possessing biocompatiblefeatures. Hence, versatile biological/biochemical sensors using conventional hydrogels based oncarbohydrates, polymers, DNA and peptides have been covered primarily. In addition, emergingconductive hydrogels possessing conducting additives such as graphene, conducting polymers, andnanocrystals have been introduced and their application in biosensors has been described extensively. Sensor operations are dependent on the changes in resistance and conductance, signal transductionthrough electrodes, sensor geometry, and interactions between sensing media and target analytes. As weprimarily focused on the type of precursor materials and the sensor performance such as sensingmechanism, sensitivity, linear range, and selectivity was summarized and presented. A trend in theresearchfields of hydrogel-based elaborate sensors has also been briefly described. This article providesessential information for advanced research in relatedfields.

Energy efficient capacitors based on graphene/conducting polymer hybrids

배준원,박정용,권오석,이창수 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.51 No.-

Graphene (GRP) and conducting polymers (CPs) are interesting classes of emerging materials for variousapplications. To date, extensive research effort has been devoted to the investigation of diverse propertiesof graphene and conducting polymers such as polypyrrole (PPy), polyaniline (PAni), and polythiophene(PTh). The combination of these materials can be very advantageous in terms of practical applications inenergy storage/conversion systems. Among various those systems, energy efficient electrochemicalcapacitors (ECs) have become popular due to the recent need for small and portable devices. Therefore, inthis article, the application of GRP/CP hybrids for high performance capacitors is described concisely. Inparticular, an extensive and concise summary on the previous research activities regarding GRP/CPcapacitors is covered. Subsequently, recent patents related to the preparation and application of GRP/CPcapacitors are also introduced briefly. It is certain that this article can provide essential information forfuture study.

Fabrication of carbon nanotubes from conducting polymer precursor as field emitter

배준원,장정식 한국공업화학회 2012 Journal of Industrial and Engineering Chemistry Vol.18 No.6

Carbon nanotubes with an average diameter of 50 nm were produced from polypyrrole nanotubes fabricated with a surfactant mediated microemulsion polymerization. A simple production of polypyrrole nanotube precursor was possible through a proper selection of surfactant and initiator in microemulsion system. A subsequent thermal treatment of conducting polymer precursor generated novel carbon nanotubes. Electron microscopy images confirmed the successful formations of polypyrrole and carbon nanotubes. A series of carbon nanotube pastes were formulated with combination of binders and fillers. The field emission characteristic of these carbon nanotubes was monitored by I–V curves. Constant current tests revealed the lifetime of carbon nanotube field emitters derived from polypyrrole nanotubes.

Fabrication of photo-crosslinkable polymer/silica sol–gel hybrid thin films as versatile barrier films

배준원,이지연,박철순,권오석,이창수 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.38 No.-

Versatile films composed of a photo-crosslinkable thiol-ene (ThE)/silica sol–gel hybrid nanocompositewere prepared using a two-step process. Tetrafunctional thiol and triene monomers were employed asprecursors to generate a matrix polymer. Tetraethyl orthosilicate (TEOS) was incorporated as the silicasource for the sol–gel process. A two-step process, sol–gel reaction followed by photocuring, resulted inuniform and transparent hybrid thin films. The formation of homogeneous, mechanically stable, andoptically transparent films was confirmed and the films were characterized by differential scanningcalorimetry (DSC) and X-ray diffraction (XRD) analyses. The morphological properties of the films wereassessed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). The thermalexpansion of the obtained membrane films was examined by thermomechanical analysis (TMA). Inaddition, optical transmission and gas permeation were assessed for high-performance applications.