Cai Chen, Nie Ziyang, Robinson J Pierce, Hussey Daniel S, LaManna Jacob M, Jacobson David L, Koenig Gary M
Department of Chemical Engineering, University of Virginia, Charlottesville 22904-4741, Virginia, United States of America.
National Institute of Standards and Technology Physical Measurements Laboratory, Gaithersburg, 20899-8461 Maryland, United States of America.
J Electrochem Soc. 2020 Nov 16;167(14). doi: 10.1149/1945-7111/abc747.
In efforts to increase the energy density of lithium-ion batteries, researchers have attempted to both increase the thickness of battery electrodes and increase the relative fractions of active material. One system that has both of these attributes are sintered thick electrodes comprised of only active material. Such electrodes have high areal capacities, however, detailed understanding is needed of their transport properties, both electronic and ionic, to better quantify their limitations to cycling at higher current densities. In this report, efforts to improve models of the electrochemical cycling of sintered electrodes are described, in particular incorporation of matrix electronic conductivity which is dependent on the extent of lithiation of the active material and accounting for initial gradients in lithiation of active material in the electrode that develop as a consequence of transport limitations during charging cycles. Adding in these additional considerations to a model of sintered electrode discharge resulted in improved matching of experimental cell measurements.
为了提高锂离子电池的能量密度，研究人员尝试增加电池电极的厚度并提高活性材料的相对比例。一种兼具这两个特性的体系是仅由活性材料组成的烧结厚电极。这种电极具有高面积容量，然而，需要详细了解其电子和离子传输特性，以便更好地量化其在更高电流密度下循环的局限性。在本报告中，描述了改进烧结电极电化学循环模型的努力，特别是纳入依赖于活性材料锂化程度的基体电子电导率，并考虑电极中活性材料锂化过程中的初始梯度，这种梯度是充电循环期间传输限制的结果。将这些额外的考虑因素添加到烧结电极放电模型中，使得实验电池测量结果的匹配性得到了改善。
