• Title/Summary/Keyword: Electrochemical Kinetics

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Electrochemical Effectiveness Factors for Butler-Volmer Reaction Kinetics in Active Electrode Layers of Solid Oxide Fuel Cells

  • Nam, Jin Hyun
    • Journal of Electrochemical Science and Technology
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    • v.8 no.4
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    • pp.344-355
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    • 2017
  • In this study, a numerical approach is adopted to investigate the effectiveness factors for distributed electrochemical reactions in thin active reaction layers of solid oxide fuel cells (SOFCs), taking into account the Butler-Volmer reaction kinetics. The mathematical equations for the electrochemical reaction and charge conduction process were formulated by assuming that the active reaction layer has a small thickness, homogeneous microstructure, and high effective electronic conductivity. The effectiveness factor is defined as the ratio of the actual reaction rate (or equivalently, current generation rate) in the active reaction layer to the nominal reaction rate. From extensive numerical calculations, the effectiveness factors were obtained for various charge transfer coefficients of 0.3-0.8. These effectiveness data were then fitted to simple correlation equations, and the resulting correlation coefficients are presented along with estimated magnitude of error.

Nanostructured Electrode Materials for Rechargeable Lithium-Ion Batteries

  • Zhao, Wei;Choi, Woosung;Yoon, Won-Sub
    • Journal of Electrochemical Science and Technology
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    • v.11 no.3
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    • pp.195-219
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    • 2020
  • Today, rechargeable lithium-ion batteries are an essential portion of modern daily life. As a promising alternative to traditional energy storage systems, they possess various advantages. This review attempts to provide the reader with an indepth understanding of the working mechanisms, current technological progress, and scientific challenges for a wide variety of lithium-ion battery (LIB) electrode nanomaterials. Electrochemical thermodynamics and kinetics are the two main perspectives underlying our introduction, which aims to provide an informative foundation for the rational design of electrode materials. Moreover, both anode and cathode materials are clarified into several types, using some specific examples to demonstrate both their advantages and shortcomings, and some improvements are suggested as well. In addition, we summarize some recent research progress in the rational design and synthesis of nanostructured anode and cathode materials, together with their corresponding electrochemical performances. Based on all these discussions, potential directions for further development of LIBs are summarized and presented.

Investigation of the Growth Kinetics of Al Oxide Film in Sulfuric Acid Solution (황산 용액에서 Al 산화피막의 생성과정 연구)

  • Chon, Jung-Kyoon;Kim, Youn-Kyoo
    • Journal of the Korean Chemical Society
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    • v.54 no.4
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    • pp.380-386
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    • 2010
  • We have investigated the growth kinetics of Al oxide film by anodization in sulfuric acid solution and the electronic properties of this film using electrochemical impedance spectroscopy. Al oxide film consisted $Al_2O_3$ was grown based on the point defect model and shown the eclctronic properties of n-type semiconductor.

Electrocatalysis of Selective Chlorine Evolution Reaction: Fundamental Understanding and Catalyst Design

  • Taejung Lim;Jinjong Kim;Sang Hoon Joo
    • Journal of Electrochemical Science and Technology
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    • v.14 no.2
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    • pp.105-119
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    • 2023
  • The electrochemical chlorine evolution reaction (CER) is an important electrochemical reaction and has been widely used in chlor-alkali electrolysis, on-site generation of ClO-, and Cl2-mediated electrosynthesis. Although precious metal-based mixed metal oxides (MMOs) have been used as CER catalysts for more than half a century, they intrinsically suffer from a selectivity problem between the CER and parasitic oxygen evolution reaction (OER). Hence, the design of selective CER electrocatalysts is critically important. In this review, we provide an overview of the fundamental issues related to the electrocatalysis of the CER and design strategies for selective CER electrocatalysts. We present experimental and theoretical methods for assessing the active sites of MMO catalysts and the origin of the scaling relationship between the CER and the OER. We discuss kinetic analysis methods to understand the kinetics and mechanisms of CER. Next, we summarize the design strategies for new CER electrocatalysts that can enhance the reactivity of MMO-based catalysts and overcome their scaling relationship, which include the doping of MMO catalysts with foreign metals and the development of non-precious metal-based catalysts and atomically dispersed metal catalysts.

Improvement of Electrochemical Reaction Kinetics in Lithium Manganese Oxide Thin Films (리튬 망간산화물 박막에서의 전극 반응의 개선)

  • Park Young-Shin;Kim Chan-Soo;Joo Seung-Ki
    • Journal of the Korean Electrochemical Society
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    • v.3 no.2
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    • pp.96-99
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    • 2000
  • In order to improve the rate capability of lithium manganese oxide thin film, we prepared the patterned cathode films by conventional lithography and etching techniques. From the investigation of discharge current density effects on discharge curves of cathode films, the rate capability was greatly improved due to increase of lithium intercalation kinetics fur charge transfer.

Function through Defects: Thermodynamic and Kinetics of Point Defects in Ionic Solids

  • Ko, Taegyung;Bang, Gyusuk;Shin, Jungmuk
    • The Korean Journal of Ceramics
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    • v.4 no.2
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    • pp.61-67
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    • 1998
  • The significance of point defects as relevant centers concerning electrochemical function is highlighted. Starting from the most simple case of dilute equilibrium bulk defect chemistry, influence of defect interaction and in particular the impact of interfaces on point defect redistribution are considered. Then recent progress in the field of kinetics in bulk and at boundaries is discussed. Finally, selected applications with emphasis on battery and sensor technology are presented.

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