We report an eco-friendly, simple, and scalable method of FeF₂ cathode production. MIL-88A was synthesized in a water medium without any additives. It was used as a source of iron (3 +) ions during pyrolysis. The porous structure of such a sacrificial agent allowed us to incorporate poly-vinylidene fluoride molecules as a guest component into a host MIL-88A framework. Pyrolysis in Ar-flow results in two simultaneous processes: reducing Fe³⁺ into Fe²⁺ and forming porous carbon shells for FeF₂ nanoparticles. Applying complex analysis of high-resolution TEM images, porosity measurements, and XANES spectroscopy, we have revealed that obtained iron fluoride is composed of nanoparticles with elongated and hexagonal shapes. Both iron fluorides were attributed to tetragonal FeF₂ structure type, contained only Fe²⁺ ions, and were covered with porous carbon shells. The obtained material was used as a cathode for a lithium-ion battery and showed good stability and a high capacity of 425–330 mA h/g. The proposed water-based synthesis of MIL-88A as a precursor in combination with mild pyrolysis conditions and good electrochemical performance make this material promising for cathode application.

我们报告了一种环保、简单且可扩展的 FeF ₂阴极生产方法。MIL-88A 是在没有任何添加剂的水介质中合成的。它在热解过程中用作铁 (3 +) 离子的来源。这种牺牲剂的多孔结构使我们能够将聚偏二氟乙烯分子作为客体成分结合到主体 MIL-88A 框架中。Ar 气流中的热解导致两个同时发生的过程：将 Fe ³⁺还原为 Fe ²⁺和形成 FeF _{2的多孔碳壳}纳米粒子。应用高分辨率 TEM 图像、孔隙率测量和 XANES 光谱的复杂分析，我们发现所获得的氟化铁由具有细长和六边形形状的纳米颗粒组成。两种氟化铁都属于四方FeF ₂结构类型，仅含有Fe ²⁺离子，并被多孔碳壳覆盖。所得材料用作锂离子电池的正极，具有良好的稳定性和 425-330 mA h/g 的高容量。所提出的 MIL-88A 的水基合成作为前体，结合温和的热解条件和良好的电化学性能，使这种材料在阴极应用方面很有前景。