• Title/Summary/Keyword: Electrode modification

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Polypyrrole-Coated Reticulated Vitreous Carbon as Anode in Microbial Fuel Cell for Higher Energy Output

  • Yuan, Yong;Kim, Sung-Hyun
    • Bulletin of the Korean Chemical Society
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    • v.29 no.1
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    • pp.168-172
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    • 2008
  • A microbial fuel cell is a noble green technology generating electricity from biomass and is expected to find applications in a real world. One of main hurdles to this purpose is the low power density. In this study, we constructed a prototype microbial fuel cell using Proteus vulgaris to study the effect of various reaction conditions on the performance. Main focus has been made on the modification of the anode with electropolymerized polypyrrole (Ppy). A dramatic power enhancement was resulted from the Ppy deposition onto the reticulated vitreous carbon (RVC) electrode. Our obtained maximum power density of 1.2 mW cm-3 is the highest value among the reported ones for the similar system. Further power enhancement was possible by increasing the ionic strength of the solution to decrease internal resistance of the cell. Other variables such as the deposition time, kinds of mediators, and amount of bacteria have also been examined.

Performance Evaluation and Modification of LCTV for Spatial Light Modulator (공간광변조기용 LCTV의 성능측정 및 개선)

  • Kwon, Won-Hyun;Kim, Nam;Pan, Jae-Kyung;Park, Han-Kyu
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.14 no.4
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    • pp.405-411
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    • 1989
  • Performance evaluation of inexpensive LCTV to function as a two-dimensional spatial light modulator is performed. Correction of the phase distortion of the device is performed using the substrate of hologram plate and index matching oil. A new method for eliminating electrode grid pattern that incorporates phase conjugation in a BaTiO3 crystal is proposed and experimented.

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Investigation of the HV Ionic Wind Generator and the Control of Corona Discharge for Air-flow Formation (기류형성을 위한 고전압 이온풍 발생장치와 코로나 제어기술에 관한 기초적 연구)

  • Lee, B.H.;Eom, J.H.;Kang, S.M.;Chang, K.C.;Ahn, C.H.
    • Proceedings of the KIEE Conference
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    • 2002.07c
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    • pp.1707-1709
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    • 2002
  • Ionic wind may be produced by DC corona discharges. In this work, the electrical effect has studied to evaluate applicability in fields of electrostatic cooling, ozone generation, electrostatic precipitation, heat transfer, air flow modification, and etc. The ionic wind velocity was measured as a function of the distance of pin to plate and the diameter of punched hole. The pin to punched-plate electrode generates airflow from pin to plate and the flow direction is controlled by the hole size of punched-plate, input voltage and distance between two electrodes. As a consequence, the ionic wind velocity is nearly proportional to the applied voltages and ranges from 1 to 3 m/sec.

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WORM Behavior of 6F-TPA PI by Hole Injection

  • Lee, Gyeong-Jae;Im, Gyu-Uk;Yang, Mi-Hyeon;Gang, Tae-Hui;Jeong, Seok-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2012.02a
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    • pp.244-244
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    • 2012
  • Polymer memory devices have attracted considerable attention because of their advantages such as low cost potential, good scalability, flexibility, simplicity in structure, and large capacity for data storage. Metal/poly (4,4'-aminotriphenylene hexafluoroisopropylidenediphthalimide) (6F-TPA PI)/metal system has been found to show an electrical bi-stable behavior. Here, we show a novel set-up of 6F-TPA PI/Al sample in which holes are injected by photoelectron emission process instead of direct charge carrier injection via metal electrode. In this process, an irreversible electrical phase transition of 6F-TPA PI is found, leading to a write-once-read-many (WORM) behavior. The photoelectron spectroscopy results measured before and after the switching process revealed that the irreversible electrical phase transition of 6F-TPA PI is attributed to the chemical modification of the carbonyl group in phthalimide moiety.

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Spectroscopic Studies of TP6F PI Switched by Hole-Injection

  • Lee, Gyeong-Jae;Im, Gyu-Uk;Kim, Dong-Min;Lee, Mun-Ho;Gang, Tae-Hui;Jeong, Seok-Min
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.297-298
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    • 2011
  • Metal/poly (4,4'-aminotriphen-ylene hexafluoroisopropylidenediphthalimide) (TP6F PI)/metal structure exhibited an electrically volatile phase transition with high (OFF) or low (ON) resistive states when voltage between electrodes swept. Here, we demonstrate a noble set-up in which holes are injected by photoelectron emission process during the voltage sweep instead of direct charge carrier injection via metal electrode, which enables direct investigation into changed electronic structures of TP6F PI both in ON and OFF states using photoemission spectroscopy methods. In the I-V measurement, TP6F PI shows a non-volatile behavior. In spectroscopic results, this non-volatile behavior is leaded from the structural modification of the O=C double bond in phthalimide of TP6F PI by hole injection.

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Cathode design and simulation in electrochemical machining (전해가공 시의 정밀도위 향상을 위한 음극 설계와 모사)

  • Yu, S. C.;Jo, S. I.;Sohn, H. J.;Kang, T.
    • Journal of the Korean institute of surface engineering
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    • v.30 no.4
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    • pp.239-247
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    • 1997
  • The electrochemical machining of carbon steel was carried in various electrolytes which contain NACl and $NaCIO_3$. Though electrolyte containg NaCl yields fast machining rate, dimensional control is rather difficult. In the case of electrolyte with $NaCIO_3$, dimensional control of anode shape can be obtained through modification of cathode design. Mathematical modeling is also performed for these systems and agreements are good compared with experimental date. The constant gap experiment butween two electrode yielded faster machining rate than constant cathode moving rate experiment.

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Investigation of charge injection in organic thin film transistor using ink-jet printed silver electrodes

  • Kim, Dong-Jo;Jeong, Sun-Ho;Lee, Sul;Jang, Dae-Hwan;Moon, Joo-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.730-732
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    • 2007
  • We fabricated a coplanar type organic thin-film transistors using ink-jet printed silver source/drain electrodes and ${\alpha},{\omega}-dihexylquaterthiophene$ (DH4T) which is an active layer. Use of ink-jet printed silver nanoparticle-based metal electrode assists the energetic mismatch with p-type organic semiconductor via modification of their interfacial properties to enable ohmic contact formation.

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Alizarin Red S modified electrochemical sensors for the detection of aluminum ion

  • Chang, Seung-Cheol
    • Journal of Sensor Science and Technology
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    • v.19 no.6
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    • pp.421-427
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    • 2010
  • Alizarin Red S modified screen printed carbon electrodes were developed for the electrochemical detection of aluminum ion. The electrodes developed use screen-printed carbon electrodes(SPCEs) coupled with chemical modification with an organic chelator, Alizarin Red S(ARS), for aluminum ion detection in aqueous solution. For sensor fabrication ARS was directly immobilized on the surface of SPCEs using PVA-SbQ(The poly(vinyl alcohol) bearing stryrylpyridinium groups). Aluminum concentrations were indirectly estimated by amperometric determination of the non-complexed ARS immobilized on the electrodes, after its complexation with aluminum. The sensitivity of the sensor developed was $3.8\;nA{\mu}M^{-1}cm^{-2}$ and the detection limit for aluminum was $25\;{\mu}M$.

Comparisons of Stability and Spectral Response of n-Si Electrodes Modified with Polyaniline and Polypyrrole in Aqueous Solutions$^1$

  • Kim, Jin-Doo;Kim, Kang-Jin;Chon, Jung-Kyoon
    • Bulletin of the Korean Chemical Society
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    • v.8 no.5
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    • pp.362-366
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    • 1987
  • Modification of n-Si electrodes coated by photogalvanostatically with polyaniline and polypyrrole in aqueous solutions considerably enhanced the stability and the spectral response of the photoelectrodes. A polypyrrole coated electrode incorporated with redox couple $Fe(CN)_{6}^{3-_6}$ / $Fe(CN)_{6}^{4-_6}$ yielded a photocurrent density of 400${\mu}A/cm^2$ for about 120 hours. Broad spectral responses over 300-850 nm were observed for both polymer coated electrodes of which polypyrrole coated one showed better current conversion efficiency.

Effective Approaches to Preventing Dendrite Growth in Lithium Metal Anodes: A Review

  • Jaeyun Ha;Jinhee Lee;Yong-Tae Kim;Jinsub Choi
    • Applied Chemistry for Engineering
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    • v.34 no.4
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    • pp.365-382
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    • 2023
  • A lithium metal anode with high energy density has the potential to revolutionize the field of energy storage systems (ESS) and electric vehicles (EVs) that utilize rechargeable lithium-based batteries. However, the formation of lithium dendrites during cycling reduces the performance of the battery while posing a significant safety risk. In this review, we discuss various strategies for achieving dendrite-free lithium metal anodes, including electrode surface modification, the use of electrolyte additives, and the implementation of protective layers. We analyze the advantages and limitations of each strategy, and provide a critical evaluation of the current state of the art. We also highlight the challenges and opportunities for further research and development in this field. This review aims to provide a comprehensive overview of the different approaches to achieving dendrite-free lithium metal anodes, and to guide future research toward the development of safer and more efficient lithium metal anodes.