Insertion compounds provide the fundamental basis of today’s commercialized Li-ion batteries. Throughout history, intense research has focused on the design of stellar electrodes mainly relying on layered oxides or sulfides, and leaving aside the corresponding halides because of solubility issues. This is no longer true. In this work, we show the feasibility of reversibly intercalating Li⁺ electrochemically into VX₃ compounds (X = Cl, Br, I) via the use of superconcentrated electrolytes (5 M LiFSI in dimethyl carbonate), hence opening access to a family of Li_xVX₃ phases. Moreover, through an electrolyte engineering approach, we unambiguously prove that the positive attribute of superconcentrated electrolytes against the solubility of inorganic compounds is rooted in a thermodynamic rather than a kinetic effect. The mechanism and corresponding impact of our findings enrich the fundamental understanding of superconcentrated electrolytes and constitute a crucial step in the design of novel insertion compounds with tunable properties for a wide range of applications including Li-ion batteries and beyond.

插入化合物提供了当今商业化锂离子电池的基础。纵观历史，大量的研究集中在主要依靠层状氧化物或硫化物的恒星电极设计上，而由于溶解度问题而忽略了相应的卤化物。这不再是真的。在这项工作中，我们展示了通过使用超浓缩电解质（碳酸二甲酯中的 5 M LiFSI）将 Li ⁺以电化学方式可逆地嵌入 VX ₃化合物（X = Cl、Br、I）中的可行性，从而打开了获得 Li 家族的途径_x VX ₃阶段。此外，通过电解质工程方法，我们明确证明超浓缩电解质对无机化合物溶解度的积极影响源于热力学而非动力学效应。我们的研究结果的机理和相应的影响丰富了对超浓缩电解质的基本理解，并构成了设计具有可调特性的新型插入化合物的关键一步，适用于包括锂离子电池等在内的广泛应用。