电极
材料科学
电阻抗
复合材料
集电器
锂(药物)
分析化学(期刊)
电解质
化学
电气工程
色谱法
医学
工程类
内分泌学
物理化学
作者
Shelley Brown,Niklas Mellgren,Michael Vynnycky,Göran Lindbergh
出处
期刊:Journal of The Electrochemical Society
[The Electrochemical Society]
日期:2008-01-01
卷期号:155 (4): A320-A320
被引量:40
摘要
High-power positive composite porous electrodes are known to be the main source of impedance increase in batteries based on GEN2 chemistry. The impedance of positive electrodes, both fresh and harvested from coin cells aged in an accelerated EUCAR hybrid electric vehicle lifetime matrix, was measured in a three-electrode setup and the results fitted with a physically based impedance model. A methodology for fitting the impedance data, including an optimization strategy incorporating a global genetic routine, was used to fit either fresh or aged positive electrodes simultaneously at different states of charge down to . The fresh electrodes had an exchange current density of approximately , a solid-phase diffusion coefficient of approximately , and a log-normal active particle size distribution with a mean radius of . Aged electrode impedance results were shown to be highly dependent on both the electrode state of charge and the pressure applied to the electrode surface. An aging scenario incorporating loss of active particles, coupled with an increase both in the local contact resistance between the active material and the conductive carbon and the resistance of a layer on the current collector, was shown to be adequate in describing the measured aged electrode impedance behavior.
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