導電性 高分子의 電氣化學的 DOPING에 의한 電氣的 特性

具轄本,朴鄭學,司空鍵 東亞大學校 1990 東亞論叢 Vol.27 No.1

Aromatic compounds such as Polyparaphenylene(PPP) and Polyparaphenylenvinylene(PPV) were polymerized by chemical and electrochemical synthesis. The electrical properties with various dopants and concentrations for the PPV and PPP were studied. The results are as follows: 1) The conductivities of PPV with BF₄dopants and I₂doped PPP were much incresed(i.e., 10 adn 6 orders, respectively) than those of without dopants. 2) The conductivities of PPV and PPP with NH₃gas were much increased(i.e., 2 and 10 orders, respectively) than those of without NH₃ gas. 3) The variations of ESR line width and spin density were in good agreement with those of polaron and bi-polaron models. As a summary, PPV and PPP were made by chemical and electrochemical synthesis could be appropriate for the gas sensors.

導電性 高分子의 電氣 傳導 機構 및 첨가물 효과

사공건,구할본,박정학 東亞大學校 大學院 1990 大學院論文集 Vol.15 No.-

A topic of this study is focused on the electrical properties by utilizing thermally stimulated current and the time-of-flight method for conducting polymers such as PCPA and PPS. The mobility of carriers between electrodes inserted polymer was measured by Scher-Montroll plot. As a summary, it is shown that the conductivity of the polymer was strongly dependent on high affinity I₂or TCNQ addivities. The reason for increasing of conductivity is believed that the carrier density and mobility of polymer by adding I₂for PCPA were increased.

Synthesis and Characterization of Silver Vanadium Oxide as a Cathode for Lithium Ion Batteries

Hal-Bon Gu,Van Hiep Nguyen 한국전기전자재료학회 2016 Transactions on Electrical and Electronic Material Vol.17 No.3

β-AgVO3 nanorods have been successfully synthesized using a soft chemistry route followed by heat treatment. Theywere characterized by X-ray diffraction and field emission scanning electron microscopy, and their electrochemicalproperties were investigated using cyclic voltammetry, impedance spectra, and charge-discharge tests. The resultsshowed that the smooth-surfaced nanorods are very uniform and well dispersed, with diameters of ~100-200 nmand lengths of the order of several macrometers. The nanorods deliver a maximum specific discharge capacity of 275mAh g-1 at 30 mA g-1. They also demonstrated good rate capability with a discharge capacity at the 100th cycle of 51mAh g-1.

Cycling Performance of LiFePO₄ as the Cathode Materials for Lithium Polymer Batteries

Gu, Hal Bon,Jun, Dae Kyoo Trans Tech Publications, Ltd. 2007 Materials science forum Vol.544 No.-

<P>The cycle behavior and rate performance of C-LiFePO4/SPE/Li cell have been investigated at 25 °C. Carbon coated LiFePO4 (C-LiFePO4) was employed as cathode and 25PVDFLiClO4EC10PC10 was used as solid polymer electrolyte (SPE). The C-LiFePO4/SPE/Li cell exhibited above 140 mAh/g of discharge capacity at 0.1 mA/cm2 and excellent reversible cyclability with a stable capacity on cycling. In addition, the discharge capacity of C-LiFePO4/SPE/Li cell was 150 mAh/g at 0.1 C (0.02 mA/cm2) and 130 mAh/g at 1 C (0.2 mA/cm2), respectively.</P>

카본 나노파이버가 도핑된 리튬이온전지의 전기화학적 특성

구할본(Gu, Hal-Bon) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

올리빈 구조의 LiFePO₄ 정극 활물질은 650?C에서 고상법으로 제조되었다. LiFePO₄의 전자전도도를 향상시키기 위하여 graphite nanofiber(GNF)를 각각 3wt%, 5wt%, 7wt%, 9wt% 첨가하여 LiFePO₄-C를 제조하였다. 제조된 분말의 입자 형태를 확인하기 위하여 X-ray diffraction(XRD)과 File Electronic Scaning Electromicroscopy(FE-SEM)를 측정하였다. XRD결과로부터 제조된 분말은 모두 순수한 결정 구조를 나타내었고 입자의 크기는 약 200nm였다. 5wt% GNF를 첨가한 LiFePO₄-C는 기타 첨가량에 비해 방전용량이 가장 높았다. 첫 사이클의 용량은 151.73mAh/g 나타났고 50 사이클 뒤에도 92% 이상을 유지하고 있었다. 첨가하지 않은 것에 비해 43% 증가하였다. LiFePO₄-C(3wt%), LiFePO₄-C(7wt%), LiFePO₄-C(9wt%)의 첫 사이클 방전용량은 각각 147.94mAh/g, 136.64mAh/g, 121.07mAh/g 나타났다. LiFePO₄-C(5wt%)에 비해 용량은 떨어쪘지만 순수한 LiFePO₄보다 많이 높았다. 임피던스 결과를 보면 기타 첨가량에 비해 LiFePO₄-C(5wt%)의 저항 제일 낮았다. 이는 충방전 결과와 일치하였다. graphite nanofiber의 첨가로 인하여 LiFePO₄ 정극 활물질의 전자전도도가 높아지고, 따라서 전기화학적 특성도 크게 향상되었다.

Electrochemical properties of metal salts polymer electrolyte for DSSC

구할본(Gu, Hal-Bon),Zhao, Xing Guan,Jin, En Mei 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

Dye-sensitized solar cell(DSSC) have been considered one of the promising alternatives to conventional solar cells, because of their low cost, easy fabrication and relatively high energy conversion efficiency. However, although the cell offers reasonable efficiency at least 11%, the use of a liquid electrolyte placed technological challenges for achieving the desired durability and operational stability of the cell. In order to prevent or reduce electrolyte leakage considerable efforts have been made, such as p-type semiconductor or organic hole-transport material that better mechanical properties and simple fabrication processes. In this work, we synthesized solid-state electrolyte containing LiI and KI metal salt with starting materials of poly ethylene oxide to substitute liquid electrolyte enhance the ionic conductivity and solar conversion efficiency. Li+ leads to faster diffusion and higher efficiency and K+ leading to higher ionic conductivity. The efficiency of poly ethylene oxide/LiI system electrolyte is 1.47% and poly ethylene oxide/potassium electrolyte is 1.21%. An efficiency of 3.24% is achieved using solid-state electrolyte containing LiI and KI concentrations. The increased solar conversion efficiency is attributed to decreased crystallinity in the polymer that leads to enhanced charge transfer.

염료감응형 태양전지용 유리분말이 함유된 고효율 광전극 페이스트 개발

구할본,Gua, Hal-Bon 한국전기전자재료학회 2011 전기전자재료학회논문지 Vol.24 No.5

Hybrid $SiO_2-TiO_2$ photoelectrode with different type of layers was investigated in dye-sensitized solar cells (DSSC). Use of a thin layer of nanocrystalline $TiO_2$ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. So, thus, it becomes necessary to include a $SiO_2-TiO_2$ layer for increase light harvesting effect such that the lower photon conversion due to thin layer could be compensated. In this paper reports the use of transparent high surface area $TiO_2$ layer and an additional $SiO_2-TiO_2$ layer, thus ensuring adequate light harvesting in these devices. The best solar conversion efficiency 6.6% under AM 1.5 was attained with a multi-layer structure using $TiO_2$ layer/$SiO_2-TiO_2$ layer/$TiO_2$ layer for the light harvesting and this had resulted to about 44% increase in photocurrent density of dye-sensitized solar cells.

표면형상 변화에 따른 염료감응 태양전지의 전기화학적 특성

구할본,Gu, Hal-Bon 한국전기전자재료학회 2012 전기전자재료학회논문지 Vol.25 No.2

We use UV(ultraviolet)-$O_3$ treatment to increase the surface area and porosity of $TiO_2$ films in dye-sensitized solar cells (DSSCs). After the UV-$O_3$ treatment, surface area and porosity of the $TiO_2$ films were increased, the increased porosity lead to amount of dye loading and solar conversion efficiency was improved. Field emission scanning electron microscopy images clearly showed that the nanocrystalline porosity of films were increased by UV-$O_3$ treatment. The Brunauer, Emmett, and Teller surface area of the $TiO_2$ films were increased from $0.71cm^2/g$ to $1.31cm^2/g$ by using UV-$O_3$ treatment for 20 min. Also, UV-$O_3$ treatment of $TiO_2$ films significantly enhanced their solar conversion efficiency. The efficiency of the films without treatment was 4.9%, and was increased to 5.6% by UV-$O_3$ treatment for 20 min. Therefore the process enhanced the solar conversion efficiency of DSSCs, and can be used to develop high sensitivity DSSCs.

Enhanced Reaction Kinetic of Fe3O4-graphite Nanofiber Composite Electrode for Lithium Ion Batteries

Wan Lin Wang,Hal-Bon Gu,박주영 한국전기전자재료학회 2014 Transactions on Electrical and Electronic Material Vol.15 No.6

A Fe3O4-graphite nanofiber composite for use as an anode material was successfully synthesized by calcining Fe2O3and graphite nanofiber (GNF) together in a N2 atmosphere. Using this Fe3O4-GNF composite in a lithium ion batteryresulted in a higher lithium storage capacity than that obtained using Fe3O4-graphite (Fe3O4-G). The Fe3O4-GNF (10wt%) electrode exhibited a higher lithium ion diffusion coefficient (2.29×10-9 cm2 s-1) than did the Fe3O4-G (10%)(3.17×10-10 cm2 s-1). At a current density of 100 mA g-1, the Fe3O4-GNF (10 wt%) anode showed a higher reversiblecapacity (1,031 mAh g-1) than did the Fe3O4-G (10%) anode (799 mAh g-1). Moreover, the Fe3O4GNF electrodes showedgood cycling performance without the addition of a conductive material.

Improving Electrochemical Properties of LiFePO4 by Doping with Gallium

Van Hiep Nguyen,Hal-Bon Gu,박주영 한국전기전자재료학회 2014 Transactions on Electrical and Electronic Material Vol.15 No.6

Ga-doped LiFePO4 cathode materials were synthesized using a hydrothermal method. The microstructuralcharacteristics and electrochemical performances were systematically investigated using field emission scanningelectron microscopy, high-resolution X-ray diffraction, energy dispersive X-ray spectroscopy, charge-dischargecycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Among the as-prepared samples,LiFe0.96Ga0.04PO4 demonstrates the best electrochemical properties in terms of discharge capacity, electrochemicalreversibility, and cycling performance with an initial discharge capacity of 125 mAh g-1 and high lithium ion diffusioncoefficient of 1.38 × 10-14 cm2 s-1 (whereas for LiFePO4, these were 113 mAh g-1 and 8.09 × 10-15 cm2 s-1, respectively). Theimproved electrochemical performance can be attributed to the facilitation of Li+ ion effective diffusion induced byGa3+ substitution.