FeS-based composites are sustainable conversion electrode materials for lithium-ion batteries, combining features like low cost, environmental friendliness, and high capacities. However, they suffer from fast capacity decay and low electron conductivity. Herein, novel insights into a surprising phenomenon of this material are provided. A FeS/Fe3 C/C nanocomposite synthesized by a facile hydrothermal method is compared with pure FeS. When applied as anode materials for lithium-ion batteries, these two types of materials show different capacity evolution upon cycling. Surprisingly, the composite delivers a continuous increase in capacity instead of the expected capacity fading. This unique behavior is triggered by a catalyzing effect of Fe3 C nanoparticles. The Fe3 C phase is a beneficial byproduct of the synthesis and was not intentionally obtained. To further understand the effect of interconnected carbon balls on FeS-based electrodes, complementary analytic techniques are used. Ex situ X-ray radiation diffraction and ex situ scanning electron microscopy are employed to track phase fraction and morphology structure. In addition, the electrochemical kinetics and resistance are evaluated by cyclic voltammetry and electrochemical impedance spectroscopy. These results reveal that the interconnected carbon balls have a profound influence on the properties of FeS-based electrodes resulting in an increased electrode conductivity, reduced particle size, and maintenance of the structure integrity.

中文翻译：

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FeS / Fe3 C / C复合电极对锂离子电池连续容量提高的影响。

FeS基复合材料是锂离子电池的可持续转换电极材料，具有低成本，环保和高容量等特点。然而，它们遭受快速容量衰减和低电子电导率的困扰。在此，提供了对该材料的令人惊讶的现象的新颖见解。通过简便的水热法合成的FeS / Fe3 C / C纳米复合材料与纯FeS进行了比较。当用作锂离子电池的负极材料时，这两种类型的材料在循环时显示出不同的容量变化。出人意料的是，复合材料的容量不断增加，而不是预期的容量下降。Fe3 C纳米颗粒的催化作用触发了这种独特的行为。Fe 3 C相是合成的有益副产物，并非有意获得。为了进一步了解互连的碳球对基于FeS的电极的影响，使用了补充分析技术。异位X射线辐射衍射和异位扫描电子显微镜用于跟踪相分数和形态结构。另外，通过循环伏安法和电化学阻抗谱评价电化学动力学和电阻。这些结果表明，相互连接的碳球对基于FeS的电极的性能具有深远的影响，从而导致电极电导率增加，粒径减小以及结构完整性得以维持。异位X射线辐射衍射和异位扫描电子显微镜用于跟踪相分数和形态结构。另外，通过循环伏安法和电化学阻抗谱评价电化学动力学和电阻。这些结果表明，相互连接的碳球对基于FeS的电极的性能具有深远的影响，从而导致电极电导率增加，粒径减小以及结构完整性得以维持。异位X射线辐射衍射和异位扫描电子显微镜用于跟踪相分数和形态结构。另外，通过循环伏安法和电化学阻抗谱评价电化学动力学和电阻。这些结果表明，相互连接的碳球对基于FeS的电极的性能具有深远的影响，从而导致电极电导率增加，粒径减小以及结构完整性得以维持。