Is small particle size more important than carbon coating?: An example study on LiFePO4 cathodes
Is small particle size more important than carbon coating?: An example study on LiFePO4 cathodes
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DOI：
10.1016/j.elecom.2007.09.020
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发表时间：
2007-12-01
影响因子：
5.4
通讯作者：
Jamnik, Janez
中科院分区：
文献类型：
--
作者：
Gaberscek, Miran;Dominko, Robert;Jamnik, Janez
基于对不同研究小组的九篇论文的仔细分析，我们首次表明，在lifepo4基阴极材料中，电极电阻仅取决于平均粒径。碳包覆的效果是边际的，只要每个LiFePO4颗粒与电极制备过程中通常添加的合理数量的炭黑颗粒点接触即可。我们提出了一个简单但一般的理论模型，可以一致地解释这一意想不到的结果。碳涂层相对不重要的主要原因是离子电导率(在RT下约为10(-11)-10（-10)S cm(-1)）远小于电子电导率(在RT下约为10（-9)S cm(-1)）。这一发现不仅对LiFePO4阴极的进一步优化，而且对制备离子电导率远低于电子电导率的其他阴极材料具有重要意义。(C) 2007 Elsevier B.V.版权所有
Based on careful analysis of nine papers by different research groups, we show, for the first time, that in LiFePO4-based cathode materials the electrode resistance depends solely on the mean particle size. The effect of carbon coating is marginal, it suffices that each LiFePO4 particle is point-contacted with a reasonable number of carbon black particles usually added in the course of electrode preparation. We present a simple but general theoretical model that consistently explains this unexpected result. The main reason for the relatively small importance of carbon coatings is the fact that the ionic conductivity (ca. 10(-11)-10(-10) S cm(-1) at RT) is much smaller than the electronic (>10(-9) S cm(-1) at RT). The present finding could be of significant importance not only for further optimization of LiFePO4 cathodes, but also for preparation of other cathode materials in which the ionic conductivity is much lower than the electronic. (C) 2007 Elsevier B.V. All rights reserved.