Irreversible vs Reversible Capacity Fade of Lithium-Sulfur Batteries during Cycling: The Effects of Precipitation and Shuttle
Irreversible vs Reversible Capacity Fade of Lithium-Sulfur Batteries during Cycling: The Effects of Precipitation and Shuttle
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DOI：
10.1149/2.0171801jes
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发表时间：
2018-01-01
影响因子：
3.9
通讯作者：
Offer, Gregory J.
中科院分区：
文献类型：
--
作者：
Marinescu, Monica;O'Neill, Laura;Offer, Gregory J.
与锂离子电池相比，锂硫电池可以提供更高的重量能量密度和更低的成本。然而，它们的大规模采用取决于许多因素，尤其是对在实际操作条件下（如部分充放电循环）决定其性能的机制的预测性理解。本工作通过实验和理论研究对部分循环的响应来解决缺乏这种理解的问题。采用锂-硫模型分析了实验观察到的部分循环响应机制。零维电化学模型跟踪了硫的时间演化，考虑了两个电化学反应，一个沉淀/溶解反应和成核反应，以及穿梭反应，可以直接获得真实的电池电荷状态。实验观察到的电压漂移是由于穿梭和溶解瓶颈之间的相互作用而产生的。其他特性则是由容量衰减引起的。我们提出了一个不可逆的硫损失与梭，如在阳极上的反应引起的模型。我们发现了可逆和不可逆对所观察到的容量衰减的贡献，并通过实验验证了由溶解瓶颈引起的可逆成分可以通过慢充电来恢复。该模型可作为循环参数优化的基础，或用于识别应用中相关的降解机制。模型代码作为补充材料b (C) The Author(s) 2017发布。由ECS出版。
Lithium-sulfur batteries could deliver significantly higher gravimetric energy density and lower cost than Li-ion batteries. Their mass adoption, however, depends on many factors, not least on attaining a predictive understanding of the mechanisms that determine their performance under realistic operational conditions, such as partial charge/discharge cycles. This work addresses a lack of such understanding by studying experimentally and theoretically the response to partial cycling. A lithium-sulfur model is used to analyze the mechanisms dictating the experimentally observed response to partial cycling. The zero-dimensional electrochemical model tracks the time evolution of sulfur species, accounting for two electrochemical reactions, one precipitation/dissolution reaction with nucleation, and shuttle, allowing direct access to the true cell state of charge. The experimentally observed voltage drift is predicted by the model as a result of the interplay between shuttle and the dissolution bottleneck. Other features are shown to be caused by capacity fade. We propose a model of irreversible sulfur loss associated with shuttle, such as caused by reactions on the anode. We find a reversible and an irreversible contribution to the observed capacity fade, and verify experimentally that the reversible component, caused by the dissolution bottleneck, can be recovered through slow charging. This model can be the basis for cycling parameters optimization, or for identifying degradation mechanisms relevant in applications. The model code is released as Supplementary material B. (C) The Author(s) 2017. Published by ECS.