• Title/Summary/Keyword: electrochemical energy

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High Energy Density Germanium Anodes for Next Generation Lithium Ion Batteries (다음세대 리튬이온 배터리용 고에너지 밀도 게르마늄 음극)

  • Ocon, Joey D.;Lee, Jae Kwang;Lee, Jaeyoung
    • Applied Chemistry for Engineering
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    • v.25 no.1
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    • pp.1-13
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    • 2014
  • Lithium ion batteries (LIBs) are the state-of-the-art technology among electrochemical energy storage and conversion cells, and are still considered the most attractive class of battery in the future due to their high specific energy density, high efficiency, and long cycle life. Rapid development of power-hungry commercial electronics and large-scale energy storage applications (e.g. off-peak electrical energy storage), however, requires novel anode materials that have higher energy densities to replace conventional graphite electrodes. Germanium (Ge) and silicon (Si) are thought to be ideal prospect candidates for next generation LIB anodes due to their extremely high theoretical energy capacities. For instance, Ge offers relatively lower volume change during cycling, better Li insertion/extraction kinetics, and higher electronic conductivity than Si. In this focused review, we briefly describe the basic concepts of LIBs and then look at the characteristics of ideal anode materials that can provide greatly improved electrochemical performance, including high capacity, better cycling behavior, and rate capability. We then discuss how, in the future, Ge anode materials (Ge and Ge oxides, Ge-carbon composites, and other Ge-based composites) could increase the capacity of today's Li batteries. In recent years, considerable efforts have been made to fulfill the requirements of excellent anode materials, especially using these materials at the nanoscale. This article shall serve as a handy reference, as well as starting point, for future research related to high capacity LIB anodes, especially based on semiconductor Ge and Si.

Electrochemical Degradation of Textile Effluent Using PbO2 Electrode in Tube Electrolyzer

  • Chao Wang; Yongqiang Li;Junmin Wan;Yi Hu;Yi Huang
    • Journal of Electrochemical Science and Technology
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    • v.15 no.1
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    • pp.190-197
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    • 2024
  • A commercial PbO2 mesh cylinder electrode was utilized as the anode for the electrochemical degradation of the textile effluent after the biological treatment with the titanium cylinder as the cathode in a self-made tube electrolyzer. The electrochemical performances of the PbO2 electrode in tube electrolyzer under different initial pH, electrolyte flow rates, current densities and times of the electrochemical degradation were investigated. The experimental results illustrated that the PbO2 electrode can reduce the chemical oxygen demand (COD) of the textile effluent from 94.0 mg L-1 to 65.0 mg L-1 with the current efficiency of 88.3%, the energy consumption of 27.7 kWh kg-1 (per kilogram of degraded COD) and the carbon emissions of 18.0 kg CO2 kg-1 (per kilogram of degraded COD) under the optimal operating conditions. In addition, the COD of the textile effluent could be reduced from 94.0 mg L-1 to 22.0 mg L-1 after the fifth electrochemical degradation. Therefore, PbO2 mesh cylinder electrode in the tube cylinder was promising for the electrochemical degradation of the textile effluent.

Study on Localized Corrosion Cracking of Alloy 600 using EN-DCPD Technique (EN-DCPD 방법을 이용한 Alloy 600 재료의 국부부식균열 연구)

  • Lee, Yeon-Ju;Kim, Sung-Woo;Kim, Hong-Pyo;Hwang, Seong-Sik
    • Corrosion Science and Technology
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    • v.12 no.2
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    • pp.93-101
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    • 2013
  • The object of this work is to establish an electrochemical noise(EN) measurement technique combined with a direct current potential drop(DCPD) method for monitoring of localized corrosion cracking of nickel-based alloy, and to analyze its mechanism. The electrochemical current and potential noises were measured under various conditions of applied stress to a compact tension specimen in a simulated primary water chemistry of a pressurized water reactor. The amplitude and frequency of the EN signals were evaluated in both time and frequency domains based on a shot noise theory, and then quantitatively analyzed using statistical Weibull distribution function. From the spectral analysis, the effect of the current application in DCPD was found to be effectively excluded from the EN signals generated from the localized corrosion cracking. With the aid of a microstructural analysis, the relationship between EN signals and the localized corrosion cracking mechanism was investigated by comparing the shape parameter of Weibull distribution of a mean time-to-failure.

Surface Treatment with Alkali Solution of Carbon Felt for Vanadium Redox Flow Battery (바나듐레독스흐름전지용 카본펠트전극의 알칼리용액을 이용한 표면개질)

  • KIM, SUNHOE;LEE, KEON JOO
    • Journal of Hydrogen and New Energy
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    • v.27 no.4
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    • pp.372-377
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    • 2016
  • The carbon felt used as the electrode of vanadium redox flow battery (VRFB) requires imprived electrochemical activity for better battery performance and efficiencies. Many efforts have been tried to improve electrochemical activity of the carbon felt as electrodes. In this study the alkali solution, KOH, is applied on surface treatment of the carbon felt electrode. The carbon felts were treated with KOH under room temperature and $80^{\circ}C$. The isopropyl alcohol was applied to improve wettability of the carbon felt during KOH treatment. The KOH treated carbon felt was analyzed by using the X-ray photoelectron spectroscopy (XPS). The XPS analysis of carbon felt electrode revealed on increase in the overall surface oxygen content of the carbon felts after KOH treatment. Also, cyclic voltametry tests showed electrochemical characteristics enhancement of the carbon felt.