Modelling transport-limited discharge capacity of lithium-sulfur cells
Modelling transport-limited discharge capacity of lithium-sulfur cells
复制标题
锂硫电池的运输限制放电容量建模
DOI：
10.1016/j.electacta.2016.10.032
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发表时间：
2016
影响因子：
6.6
通讯作者：
G. Offer
中科院分区：
文献类型：
--
作者：
Teng Zhang;M. Marinescu;S. Walus;G. Offer
锂硫（Li-S）电池可以带来电池技术的飞跃，其潜在的比能量密度为500 - 600 Wh/kg。进一步提高锂硫电池比能量密度的一个关键挑战是了解在低电解质负载和高放电电流下降低硫利用率的机制。虽然已经开发了几种Li-S模型来探索Li-S电池的放电机制，但到目前为止，它们未能捕获高电流下的放电曲线。在这项研究中，我们提出，在浓电解质中缓慢的离子传输限制了锂硫电池的倍率性能。通过一维Li-S模型证明了这种传输限制机制，该模型定性地捕获了基于环丁砜的Li-S电池在不同电流下的放电容量。此外，我们的模型预测放电的Li-S电池能够在短时间内恢复一定的容量。这种容量恢复现象的实验验证了不同的放电电流和弛豫时间。锂硫电池的输运限制放电行为突出了优化锂硫电池中电解质装载和电解质输运性质的重要性。
Lithium-sulfur (Li-S) battery could bring a step-change in battery technology with a potential specific energy density of 500 - 600 Wh/kg. A key challenge for further improving the specific energy-density of Li-S cells is to understand the mechanisms behind reduced sulfur utilisation at low electrolyte loadings and high discharge currents. While several Li-S models have been developed to explore the discharge mechanisms of Li-S cells, they so far fail to capture the discharge profiles at high currents. In this study, we propose that the slow ionic transport in concentrated electrolyte is limiting the rate capability of Li-S cells. This transport-limitation mechanism is demonstrated through a one-dimensional Li-S model which qualitatively captures the discharge capacities of a sulfolane-based Li-S cell at different currents. Furthermore, our model predicts that a discharged Li-S cell is able regain some capacity with a short period of relaxation. This capacity recovery phenomenon is validated experimentally for different discharge currents and relaxation durations. The transport-limited discharge behavior of Li-S cells highlights the importance of optimizing the electrolyte loading and electrolyte transport property in Li-S cells.
DOI：
10.1039/c5cp05755h
发表时间：
2016-01
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
--
作者：
M. Marinescu;Teng Zhang;G. Offer
通讯作者：
M. Marinescu;Teng Zhang;G. Offer