Metal–Sulfur (Li/Na–S) battery technology is considered one of the most promising energy storage systems because of its high specific capacity of 1675 mA h/g, attributed to sulfur. However, the rapid capacity degradation, mainly caused by metallic polysulfide dissolution, remains a significant challenge prior to practical applications. This work demonstrates for the first time that a Fe-based metal organic framework (MIL-100(Fe)) can remarkably stabilize the electrochemical behavior of sulfur-cathodes in Metal-S cells during prolonged cycling. The chemical and morphological properties of MIL-100(Fe) and, especially conjugated with their textural characteristics, can help immobilize lithium/sodium polysulfides within the highly microporous cathode structure. Capacity loss per cycle is 0.044 mA h after 3000 cycles at 2C in Li–S cells. This behavior is confirmed when the MOF-based cathode is studied in RT Na–S batteries, managing to stabilize the capacity with a loss of less than 0.08 % during 2000 cycles at 0.1 C-rate. The excellent performance can be attributed to the synergistic effects of the highly microporous structure of MOF-100(Fe), which provide an ideal matrix to confine polysulfides, and the presence of Fe(III) active centers that provide chemical affinities to sulfur and polysulfides. These factors contribute to the excellent cycling performance of the S@MIL-100(Fe) composite in Metal-Sulfur batteries.

中文翻译：

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MIL-100(Fe) MOF 作为超长周期金属硫电池的新兴硫主体阴极


金属硫 (Li/Na-S) 电池技术被认为是最有前途的储能系统之一，因为它的比容量高达 1675 mA h/g（归因于硫）。然而，主要由金属多硫化物溶解引起的快速容量衰减仍然是实际应用之前的重大挑战。这项工作首次证明，铁基金属有机骨架（MIL-100（Fe））可以在长时间循环过程中显着稳定金属-S电池中硫阴极的电化学行为。 MIL-100(Fe) 的化学和形态特性，特别是与其结构特征相结合，可以帮助将多硫化锂/多硫化钠固定在高度微孔的阴极结构内。 Li-S 电池在 2C 下循环 3000 次后，每个循环的容量损失为 0.044 mA h。当在 RT Na-S 电池中研究基于 MOF 的阴极时，这种行为得到了证实，在 0.1 C 倍率下进行 2000 次循环期间，设法稳定容量，损失小于 0.08%。优异的性能可归因于MOF-100(Fe)的高度微孔结构的协同效应，它提供了限制多硫化物的理想基质，以及Fe(III)活性中心的存在，为硫和多硫化物提供了化学亲和力。这些因素使得 S@MIL-100(Fe) 复合材料在金属硫电池中具有优异的循环性能。