Studies on LiFePO4 as cathode material using impedance spectroscopy
Studies on LiFePO4 as cathode material using impedance spectroscopy
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DOI：
10.1016/j.jpowsour.2010.09.121
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发表时间：
2011-06-15
影响因子：
9.2
通讯作者：
Ivers-Tiffee, Ellen
中科院分区：
文献类型：
--
作者：
Schmidt, Jan Philipp;Chrobak, Thorsten;Ivers-Tiffee, Ellen
磷酸铁锂是一种很有前途的用于混合动力电动汽车（HEV）的阴极材料，由于降低了热失控的风险，其满足循环期间良好的稳定性和安全操作的要求。然而，缓慢的固态扩散和差的导电性降低了功率容量。为了进一步改进，速率决定过程的识别是必要的。电化学阻抗谱（EIS）已被证明是表征电化学体系的有力工具。在这方面的贡献的弛豫时间（DRTs）的分布的阻抗的反卷积是用来在频域中获得更好的分辨率。因此，相关的损失过程进行了识别和阻抗模型的开发。使用DRT和CNLS拟合可以确定所有相关损耗过程的时间常数和极化电阻。此外，它们的温度行为进行了研究，并提供了物理解释。(C)2010 Elsevier B.V.保留所有权利。
Lithium iron phosphate is a promising cathode material for the use in hybrid electrical vehicles (HEV) meeting the demands of good stability during cycling and safe operation due to reduced risk of thermal runaway. However, slow solid state diffusion and poor electrical conductivity reduce power capability. For further improvement, the identification of the rate determining processes is necessary. Electrochemical impedance spectroscopy (EIS) has proven to be a powerful tool for the characterization of electrochemical systems. In this contribution a deconvolution of the impedance with the distribution of relaxation times (DRTs) is used to obtain a better resolution in frequency domain. Therewith, the relevant loss processes are identified and an impedance model is developed. Using DRT and CNLS-fit allows the determination of time constants and polarization resistances of all relevant loss processes. Furthermore, their temperature behavior is studied and a physical interpretation is provided. (C) 2010 Elsevier B.V. All rights reserved.