An Electrochemical Impedance Spectroscopic Study of the Electronic and Ionic Transport Properties of Spinel LiMn2O4
An Electrochemical Impedance Spectroscopic Study of the Electronic and Ionic Transport Properties of Spinel LiMn2O4
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DOI：
10.1021/jp9109157
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发表时间：
2010-04
影响因子：
3.7
通讯作者：
Q. Zhuang;T. Wei;Li-Li Du-Li;Yong-li Cui;Liang Fang;Shigang Sun
中科院分区：
文献类型：
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作者：
Q. Zhuang;T. Wei;Li-Li Du-Li;Yong-li Cui;Liang Fang;Shigang Sun
研究了尖晶石LiMn2O4在初始充放电过程中，不同电势和温度下锂离子插入和脱插入的电化学阻抗谱（EIS）。结果表明，在中等插层度处，Nyquist图中出现了三个半圆。这种新现象已经通过EIS测量作为温度的函数进行了研究。发现高频半圆和中高频半圆在20°C以上开始重叠，这表明文献中通常在室温下得到的高频压缩半圆可能由两个半圆组成。这表明锂嵌入材料的电子输运和离子输运性质的影响在低温下的EIS光谱中明显表现为单独的特征。一种新的等效电路，除了电荷传输外，还包括与电子和离子传输有关的元件。
Electrochemical impedance spectra (EIS) for lithium ion insertion and deinsertion in spinel LiMn2O4 were obtained at different potentials and different temperatures during initial charge−discharge cycle. The results revealed that, at intermediate degrees of intercalation, three semicircles appeared in the Nyquist diagram. This new phenomenon has been investigated through EIS measurements as a function of temperature. It has found that the high frequency semicircle and the middle to high frequency semicircle begin to overlap each other above 20 °C, which indicates that the high frequency compressed semicircle commonly obtained at room temperature in the literature may consist of two semicircles. This signifies that the effects of the electronic and ionic transport properties of lithium intercalation materials clearly appear as separate features in the EIS spectra at low temperatures. A new equivalent circuit that includes elements related to the electronic and ionic transport, in addition to the charge tra...