Sulfur Speciation in Li-S Batteries Determined by Operando X-ray Absorption Spectroscopy
Sulfur Speciation in Li-S Batteries Determined by Operando X-ray Absorption Spectroscopy
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DOI：
10.1021/jz401763d
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发表时间：
2013-10-03
影响因子：
5.7
通讯作者：
Nazar, Linda F.
中科院分区：
文献类型：
--
作者：
Cuisinier, Marine;Cabelguen, Pierre-Etienne;Nazar, Linda F.
电化学储能中最具挑战性的问题之一是为工作电池开发具有洞察力的氧化还原过程原位探针。对于……尤其如此。以化学转化为基础的电池，如Li-S和Li-O-2，由于中间物质的无定形性质，控制容量和循环稳定性的因素很难获得。在这里，我们研究了Li-S电池的阴极，由硫吸收的坚固的球形碳壳组成，具有定制的孔隙率，具有出色的循环稳定性。其高度规则的纳米尺度和薄碳壳允许高度均匀的电化学响应，并进一步通过S - k边缘的操作和x射线吸收光谱直接监测电池内整个氧化还原范围内的硫形态。研究结果首次揭示了硫氧化还原化学对循环机制的详细证据，显示了硫组分（在利用中）和硫化物沉淀如何影响容量。这些信息对于促进锂硫电池的改进至关重要。
Among the Most challenging I. issues in electrochemical energy storage is developing insightful in situ probes of redox processes for a working cell. This is particularly true for. cells that operate on the basis of chemical transformations such as Li-S and Li-O-2, where the factors that govern capacity and cycling stability are difficult to access owing to the amorphous nature of the intermediate species. Here, we investigate cathodes for the Li-S cell comprised of sulfur-imbibed robust spherical carbon shells with tailored porosity that exhibit excellent cycling stability. Their highly regular nanoscale dimensions and thin carbon shells allow highly uniform electrochemical response and further enable direct monitoring of sulfur speciation Within the cell over the entire redox range by operand X-ray absorption spectroscopy on the S K-edge. The results reveal the first detailed evidence of the mechanisms of sulfur redox chemistry on cycling, showing how sulfur fraction (under utilization) and sulfide precipitation impact Capacity. Such information is critical for promoting improvements in Li-S batteries.