Burns David A, Baumann Avery E, Bennett Kevin J, Díaz José C, Thoi V Sara
Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States.
Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, United States.
ACS Appl Mater Interfaces. 2021 Nov 3;13(43):50862-50868. doi: 10.1021/acsami.1c12129. Epub 2021 Oct 20.
Demands for energy storage and delivery continue to rise worldwide, making it imperative that reliable performance is achievable in diverse climates. Lithium-sulfur (Li-S) batteries offer a promising alternative to lithium-ion batteries owing to their substantially higher specific capacity and energy density. However, improvements to Li-S systems are still needed in low-temperature environments where polysulfide clustering and solubility limitations prohibit complete charge/discharge cycles. We address these issues by introducing thiophosphate-functionalized metal-organic frameworks (MOFs), capable of tethering polysulfides, into the cathode architecture. Compared to cells with the parent MOFs, cells containing the functionalized MOFs exhibit greater capacity delivery and decreased polarization for a range of temperatures down to -10 °C. We conduct thorough electrochemical analyses to ascertain the origins of performance differences and report an altered Li-S redox mechanism enabled by the thiophosphate moiety. This investigation is the first low-temperature Li-S study using MOF additives and represents a promising direction in enabling energy storage in extreme environments.
全球对能量存储和传输的需求持续增长，这使得在各种气候条件下实现可靠性能变得至关重要。锂硫（Li-S）电池因其显著更高的比容量和能量密度，为锂离子电池提供了一种有前景的替代方案。然而，在低温环境中，多硫化物聚集和溶解度限制阻碍了完整的充放电循环，因此仍需要改进Li-S系统。我们通过将能够束缚多硫化物的硫代磷酸官能化金属有机框架（MOF）引入阴极结构来解决这些问题。与含有母体MOF的电池相比，含有官能化MOF的电池在低至-10°C的一系列温度下表现出更大的容量传输和极化降低。我们进行了全面的电化学分析，以确定性能差异的根源，并报告了硫代磷酸部分促成的Li-S氧化还原机制的改变。这项研究是首次使用MOF添加剂进行的低温Li-S研究，代表了在极端环境中实现能量存储的一个有前景的方向。
