Lithium–sulfur batteries hold an immense amount of potential as next-generation energy storage devices due to their ultrahigh theoretical energy density.
Scientists created an effective redox mediator to promote the sulfur redox kinetics under practical working conditions. Image Credit: Nano Research, Tsinghua University Press.
But the actual energy density of lithium–sulfur batteries seems to be distant from the theoretical value due to the severe limitations of the cathode as a result of the slow sulfur oxidation–reduction (redox) reactions’ kinetics.
The research group has made a redox mediation strategy that is efficient and drives lithium–sulfur batteries toward practical application.
The research group reported their findings in theNano Researchjournal on June 21st, 2022.
目前，锂电池在从便携式电子设备和电动汽车到网格尺度储能系统的应用中广泛使用。在几个锂电池中，锂离子电池最受欢迎。
But lithium-ion batteries are approaching their theoretical energy density limit and cannot emulate the needs of high-energy-density energy storage devices.
The lithium–sulfur batteries, along with their ultra-high theoretical energy density of 2600 Wh kg−1, are gaining huge attraction as a possible alternative to the lithium-ion batteries
In addition to their high-energy-density potential, the sulfur utilized as the active material in the cathode seems to be affordable, eco-friendly, and naturally abundant.
但是有一个很大的障碍要克服。锂 - 硫硫电池中的高理论能量密度来自锂阳极和硫阴极之间的反应。
在放电过程时，当化学能转化为电能时，将硫溶于多硫化锂，然后再溶解为硫化锂。
However, when this conversion process happens, the kinetics, or rate of the chemical reactions, is quite slow. This sluggishness would be further provoked under rough practical working conditions.
为了解决缓慢动力学的挑战，科学家已经开发了一系列启动子来增强电池的反应。这样的启动子倾向于在锂 - 硫磺电池中充当硫宿主或层间材料，并旨在鼓励电池的动力学。亚博网站下载
但是，即使在此类启动子的帮助下，由于固体硫化物沉积物倾向于在电催化活性位点积聚，电池的性能也会缓慢下降。
借助其他研究，科学家已经确定可溶性氧化还原介体有效地鼓励动力学。氧化还原（氧化还原）缩写，解释了发生的化学反应。这样的氧化还原介质可以化学降低或氧化锂多硫化物，并在电极表面进一步再生。
科学家已经证明，使用氧化还原介质绝对是解决硬币电池中存在的动力学缓慢动力学的有效机制。此外，硬币细胞（也称为纽扣细胞）是紧凑的平板电池，可以在较小的设备（例如汽车钥匙，助听器或医疗植入物）中找到应用。
What was required next was a redox mediator that functioned in pouch cell lithium batteries, which are utilized in higher power applications, like automotive and military applications.
研究小组认为有必要开发高级氧化还原介质，这是紧急的实际工作锂溶解袋细胞的理想选择。因此，研究小组在一个有机分子的帮助下开发了一个氧化还原介质，称为5,7,12,14-五苯甲酸或PT。这有助于鼓励在高能密度锂 - 硫囊细胞中的硫氧化还原动力学。
Concretely, the PT redox mediator provides a chemical bypass for the reduction of lithium polysulfide to lithium sulfide, thus reducing the reaction resistance and improving the deposition capacity.
Bo-Quan Li, Academic Researcher, Beijing Institute of Technology
The work of the research team offers an efficient redox mediator for polysulfide reduction along with quick kinetics and confirms the application potential of sophisticated redox mediators in practical high-energy-density lithium–sulfur batteries.
展望未来，下一步将是开发高级氧化还原介质，以对阴极硫氧化还原动力学的全范围调节。借助这种高级介体，将通过电解质设计或启动锂宿主来保护锂金属阳极。
最终目标是实现低成本和高安全性的高能密度和长循环锂硫电话。这种锂 - 硫磺电池的潜在应用可能是航空车和航天器.
Bo-Quan Li, Academic Researcher, Beijing Institute of Technology
The study authors included in the research team are Yan-Qi Peng, Meng Zhao, Zi-Xian Chen, Qian Cheng, Yiran Liu, Bo-Quan Li, and Jia-Qi Huang from Beijing Institute of Technology; and Xi-Yao Li and Yun-Wei Song, fromTsinghua University.
这项研究得到了国家关键研究与发展计划，北京自然科学基金会，中国自然科学基金会，山西省的科学和技术关键项目以及北京年轻学者研究基金会计划。亚博老虎机网登录
Journal Reference:
Peng，Y.-Q.，et al. (2022) Boosting sulfur redox kinetics by a pentacenetetrone redox mediator for high-energy-density lithium-sulfur batteries.Nano Research.doi.org/10.1007/s12274-022-4584-z.
Source:http://www.tup.tsinghua.edu.cn/