• 폴리머
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• 제29권4호
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• pp.403-407
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• 2005

본 연구에서는 mobil crystalline material-41(MCM-41)의 함량 변화에 따른 고체 고분자 전해질(solid polymer electrolyte, SPE)의 이온전도도의 변화를 고찰하기 위하여, poly(ethylene oxide)(PEO), 메조포러스 기공 구조를 가지는 MCM-41 분자체, 그리고 리튬염을 이용하여 SPE를 제조하였다. SPE의 결정화도는 X-선 회절분석(XRD) 및 시차주사열량계(DSC)를 통하여 살펴보았으며, 주파수반응분석(FRA)으로 이온전도도를 측정하여 이온 전도거동을 고찰하였다. 그 결과, MCM-41을 고분자 혼합물에 첨가함에 따라 PEO의 견정성 영역의 성장을 억제할 수 있었으며, 이는 MCM-41이 메조포러스한 구조를 가지고 있기 때문이다. 또한, $P(EO)_{16}LiClO_4$/MCM-41 전해질 복합체의 이온 전도도는 8$wt\%$의 MCM-41을 첨가한 경우 가장 큰 이온전도도를 가지며, 8$wt\%$이상에서는 다소 감소된 이온전도도를 가짐을 관찰할 수 있었다. 이러한 이온전도도의 특성은 MCM-41의 첨가에 따른 고분자의 결정화도 변화와 밀접한 관계를 맺고 있다.

• 전기화학회지
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• 제17권2호
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• pp.86-93
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• 2014

5 nm의 중형기공(mesopore)을 지녔으며 5~7 nm 굵기의 산화주석($SnO_2$) 나노선 다발이 잘 정렬된 meso-$SnO_2$를 주형합성법을 이용해서 제조하였다. 또한 주형합성법을 변형시켜서 5~7 nm 굵기의 동일한 나노선 다발 사이에 존재하는 중형기공에 주형으로 사용되었던 실리카($SiO_2$)를 일부 남긴 meso-$SnO_2$와 실리카의 복합체인 meso-$SnO_2$/$SiO_2$도 제조하였다. X-선 회절, 질소흡착법, 투과전자현미경을 이용해서 meso-$SnO_2$와 meso-$SnO_2$/$SiO_2$의 구조를 확인하였다. meso-$SnO_2$/$SiO_2$는 meso-$SnO_2$에 비해서 충방전시 발생하는 부피 팽창을 완화할 수 있을 것으로 예측했으며, 순환전압전류곡선, 교류 임피던스 분석, 충방전 전압 Profile 변화를 통해 부피 팽창 완화 효과를 확인하였다. 하지만, 수명 특성 측면에서는 구조 제어 효과가 미비하여, 향후 이를 개선하는 연구가 진행되어야 한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.429-429
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• 2016

Organolead halide perovskite have attracted much attention over the past three years as the third generation photovoltaic due to simple fabrication process via solution process and their great photovoltaic properties. Many structures such as mesoporous scaffold, planar heterojunction or 1-D TiO2 or ZnO nanorod array structures have been studied to enhance performances. And the photovoltaic performances and carrier transport properties were studied depending on the cell structures and shape of perovskite film. For example, the perovskite cell based on TiO2/ZnO nanorod electron transport materials showed higher electron mobility than the mesoporous structured semiconductor layer due to 1-D direct pathway for electron transport. However, the reason for enhanced performance was not fully understood whether either the shape of perovskite or the structure of TiO2/ZnO nanorod scaffold play a dominant role. In this regard, for a clear understanding of the shape/structure of perovskite layer, we applied anodized aluminum oxide material which is good candidate as the inactive scaffold that does not influence the charge transport. We fabricated vertical one dimensional (1-D) nanostructured methylammonium lead mixed halide perovskite (CH3NH3PbI3-xClx) solar cell by infiltrating perovskite in the pore of anodized aluminum oxide (AAO). AAO template, one of the common nanostructured materials with one dimensional pore and controllable pore diameters, was successfully fabricated by anodizing and widening of the thermally evaporated Al film on the compact TiO2 layer. Using AAO as a scaffold for perovskite, we obtained 1-D shaped perovskite absorber, and over 15% photo conversion efficiency was obtained. I-V measurement, photoluminescence, impedance, and time-limited current collection were performed to determine vertically arrayed 1-D perovskite solar cells shaped in comparison with planar heterojunction and mesoporous alumina structured solar cells. Our findings lead to reveal the influence of the shape of perovskite layer on photoelectrical properties.

• Bulletin of the Korean Chemical Society
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• 제32권5호
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• pp.1507-1510
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• 2011

In this study, mercury vapor adsorption behaviors for some kinds of porous materials having various pore structures were investigated. The specific surface area and pore structures were studied by BET and D-R plot methods from $N_2$/77 K adsorption isotherms. It was found that the micropore materials (activated carbons, ACs) showed the highest mercury adsorption capacity. In a comparative study of mesoporous materials (SBA-15 and MCM-41), the adsorption capacity of the SBA-15 was higher than that of MCM-41. From the pore structure analysis, it was found that SBA-15 has a higher micropore fraction compared to MCM-41. This result indicates that the mercury vapor adsorptions can be determined by two factors. The first factor is the specific surface area of the adsorbent, and the second is the micropore fraction when the specific surface areas of the adsorbent are similar.

• Transactions on Electrical and Electronic Materials
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• 제12권3호
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• pp.123-126
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• 2011

Titanium dioxide ($TiO_2$) thin films were deposited by the sol-gel method with a surfactant-assisted mechanism. Its application for dye-sensitized solar cells (DSSCs) was investigated. Brunauer-Emmett-Teller, X-ray diffraction and field emission scanning electron microscopy techniques were used to characterize the surface characteristics of thin films. Photovoltaic-current density measurements were performed to determine the photoelectrochemical properties of the thin films and the performance of DSSCs. Energy conversion efficiency of about 6.1% was achieved for cells with conductive glass under illumination with AM 1.5 (100 $mWcm^{-2}$) simulated sunlight. Investigation showed higher photo-energy conversion efficiency for mesoporous $TiO_2$ nanocrystalline films used in DSSCs relative to commercially available Degussa P25 films.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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• pp.425-427
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• 2000

We describe the preparation of a cobalt oxide in which the solid-pore architecture of the material is controllably varied. All $CoO_2$ gels derived from $CoCl_2$-based sol-gel synthesis, but exhibit markedly different final pore structures based on how the pore fluid is removed from forces that result from extraction are either low or nonexistent. These nanoscale mesoporous materials have higher $CoO_2$ crystallites. Controlling both the pore and solid architecture on the nanoscale offers a strategy for the design of new supercapacitor and charge-storage materials.

• 한국재료학회지
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• 제26권12호
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• pp.696-703
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• 2016

In this study, we intensively investigated the effect of conductive additive amount on electrochemical performance of organic supercapacitors. For this purpose, we assembled coin-type organic supercapacitor cells with a variation of conductive additive(carbon black) amount; carbon aerogel and polyvinylidene fluoride were employed as active material and binder, respectively. Carbon aerogel, which is a highly mesoporous and ultralight material, was prepared via pyrolysis of resorcinol-formaldehyde gels synthesized from polycondensation of two starting materials using sodium carbonate as the base catalyst. Successful formation of carbon aerogel was well confirmed by Fourier-transform infrared spectroscopy and $N_2$ adsorption-desorption analysis. Electrochemical performances of the assembled organic supercapacitor cells were evaluated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy measurements. Amount of conductive additive was found to strongly affect the charge transfer resistance of the supercapacitor electrodes, leading to a different optimal amount of conductive additive in organic supercapacitor electrodes depending on the applied charge-discharge rate. A high-rate charge-discharge process required a relatively high amount of conductive additive. Through this work, we came to conclude that determining the optimal amount of conductive additive in developing an efficient organic supercapacitor should include a significant consideration of supercapacitor end use, especially the rate employed for the charge-discharge process.

• Bulletin of the Korean Chemical Society
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• 제35권1호
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• pp.103-110
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• 2014

Sisal fiber, an agricultural resource abundantly available in china, has been used as raw material to prepare activated carbon with high surface area and huge pore volume by chemical activation with zinc chloride. The orthogonal test was designed to investigate the influence of zinc chloride concentration, impregnation ratio, activation temperature and activation time on preparation of activated carbon. Scanning electron micrograph, Thermo-gravimetric, $N_2$-adsorption isotherm, mathematical models such as t-plot, H-K equation, D-R equation and BJH methods were used to characterize the properties of the prepared carbons and the activation mechanism was discussed. The results showed that $ZnCl_2$ changed the pyrolysis process of sisal fiber. Characteristics of activated carbon are: BET surface area was $1628m^2/g$, total pore volume was $1.316m^3/g$ and ratio of mesopore volume to total pore volume up to 94.3%. These results suggest that sisal fiber is an attractive source to prepare mesoporous high-capacity activated carbon by chemical activation with zinc chloride.

• 공업화학
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• 제22권2호
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• pp.173-177
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• 2011

본 연구에서는 정수장의 alum 슬러지로부터 $AlPO_4$-계 다공성 물질의 합성과정을 규명하고자 가정용 세제, 휴믹산, 아미노산 등과 같은 유기물질을 틀로 사용하여 $Al(OH)_3$과 인산으로부터 $AlPO_4$-계 다공성 물질을 합성하였으며, $600^{\circ}C$의 공기 중에서 소성을 통하여 틀로 사용한 유기물질을 제거하였다. X-선 회절 분석 결과 합성된 물질은 $AlPO_4$-계 다공성 물질의 특징적인 패턴을 나타내었으며, 물질의 형태적인 특성은 주사전자현미경을 이용하여 관찰하였다. $^{27}Al$ MAS NMR 분석을 통하여 $Al^{3+}$ 이온 주변의 화학적 배위환경의 변화를 관찰하였다. 소성 전 물질에는 4배위와 6배위된 $Al^{3+}$ 이온이 함께 존재하지만, 소성 후 물질에서 $Al^{3+}$ 이온은 모두 4배위 환경에 존재하였다. 합성된 고체 내부에 형성된 기공은 BET 비표면적 측정으로 확인하였다. 최종적으로 합성된 물질의 응용으로 공기 중 유해 포름알데히드 제거 실험을 실시하였으며, 포름알데히드 분자가 물질에 존재하는 기공 표면에 흡착됨을 확인하였다. 결론적으로, alum 슬러지로부터 얻어진 $AlPO_4$-계 다공성 재료를 유해 기체의 흡착 및 제거에 활용할 수 있는 가능성을 제시하였다.

• 한국자기공명학회논문지
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• 제3권2호
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• pp.109-126
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• 1999

The location of Cu(II) exchanged into measoporous aluminosilicate MCM-41(AlMCM-41) material and its interaction with various adsorbate molecules were investigated by electron spin resonance and electron spin echo modulation spectroscopies. Cu(II) is fully coordinated to adsorbates in a wide open mesopore of AlMCM-41 for the formation of favorable complexes. It was found that in the fresh hydrated material, Cu(II) is octahedrally coordinated to six water molecules as evidenced by an isotropic room temperature ESR signal. This species is located in a cylindrical MCM-41 channel and rotates rapidly at room temperature. Evacuation at room temperature removes some of these water molecules, leaving the Cu(II) coordinated to less water molecules and anchored to oxygens in an MCM-41 channel wall. Dehydration at 450$^{\circ}C$ produces one Cu(II) species located on the internal wall of a channel, which is easily accessible to adsorbates. Adsorption of adsorbate molecules such as water, methanol, ammonia, pyridine, aniline, acetonitrile, benzene, and ethylene on a dehydrated Cu-AlMCM-41 material causes changes in the ESR spectrum of Cu(II), indicating the complex formation with these adsorbates. Cu(II) forms a complex with six molecules of methanol as evidenced by an isotropic room temperature ESR signal and ESEM analysis like upon water adsorption. Cu(II) also forms a square planar complex containing four molecules of N-containing adsorbates such as ammonia, pyridine and aniline based on resolved nitrogen superhyperfine interaction and their ESR parameters. However, Cu(II) forms a complex with six-molecules of acetonitrile based on ESR parameters. Only one molecule of benzene or ethylene is coordinated to Cu(II).