A zero dimensional model of lithium-sulfur batteries during charge and discharge.
A zero dimensional model of lithium-sulfur batteries during charge and discharge.
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DOI：
10.1039/c5cp05755h
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发表时间：
2016-01
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影响因子：
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通讯作者：
M. Marinescu;Teng Zhang;G. Offer
中科院分区：
文献类型：
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作者：
M. Marinescu;Teng Zhang;G. Offer
锂硫电池由于其大的能量密度、安全性和可能的低成本而呈现出对锂离子电池的有吸引力的替代方案。它们的成功商业化取决于提高其性能，但也取决于对潜在机制的充分理解，以允许开发可操作细胞的预测模型。为了解决后者，我们提出了一个零维模型，该模型预测了在充电和放电期间锂硫电池的行为中观察到的许多特征。该模型占两个电化学反应，通过能斯特配方，通过巴特勒-沃尔默动力学的功率限制，和沉淀/溶解的一个物种，包括成核。它表明，典型的锂硫电池放电的低电压平台的平坦形状是由沉淀。在充电期间，预计溶解可以充当瓶颈，因为对于足够大的电流，溶解的量变得有限。这导致降低的充电容量和高平台反应的较早开始，使得两个电压平台合并。通过包括这些效应，该模型改进了现有的零维模型，同时需要比一维模型少得多的输入参数和计算资源。该模型还预测，由于沉淀，从低速率放电实验获得开路电压的常规方法可能不适合锂硫。该模型可为机理研究、识别真实的电池中的主导效应、预测实际负载下的操作行为以及应用的控制算法提供基础。
Lithium-sulfur cells present an attractive alternative to Li-ion batteries due to their large energy density, safety, and possible low cost. Their successful commercialisation is dependent on improving their performance, but also on acquiring sufficient understanding of the underlying mechanisms to allow for the development of predictive models for operational cells. To address the latter, we present a zero dimensional model that predicts many of the features observed in the behaviour of a lithium-sulfur cell during charge and discharge. The model accounts for two electrochemical reactions via the Nernst formulation, power limitations through Butler-Volmer kinetics, and precipitation/dissolution of one species, including nucleation. It is shown that the flat shape of the low voltage plateau typical of the lithium-sulfur cell discharge is caused by precipitation. During charge, it is predicted that the dissolution can act as a bottleneck, because for large enough currents the amount that dissolves becomes limited. This results in reduced charge capacity and an earlier onset of the high plateau reaction, such that the two voltage plateaus merge. By including these effects, the model improves on the existing zero dimensional models, while requiring considerably fewer input parameters and computational resources than one dimensional models. The model also predicts that, due to precipitation, the customary way of experimentally obtaining the open circuit voltage from a low rate discharge might not be suitable for lithium-sulfur. This model can provide the basis for mechanistic studies, identification of dominant effects in a real cell, predictions of operational behaviour under realistic loads, and control algorithms for applications.