Green Synthesis of Pseudocoherent Fluoride Cathode Materials from Wastes

Due to fluorine's high electronegativity, which facilitates the highest discharge plateau and exceptional energy density, transition metal fluorides (TMFs) are considered one of the most promising cathode materials for lithium-ion batteries. However, the complexity and toxicity of the synthesis process as well as the durability of TMFs hinder their wide application. Herein, we present a green synthesis strategy of iron fluorides (FeF_x), utilizing recycled polytetrafluoroethylene as fluorine source, combined with Fe powder through mechanochemical ball-milling at ambient conditions (35 °C). Benefiting from the coupling reaction between pseudocoherent FeF_x and semi-ionic CF_y, the resulting FeF_x-CF_y cathode delivers an impressive capacity of 240.0 mAh g^-1 and maintains 76.2% after 2000 cycles at 1C, obviously surpassing the prevailing LiNi_0.8Co_0.1Mn_0.1O₂ and LiFePO₄ cathodes. This work not only introduces a sustainable strategy for synthesizing high-performance and high value-added fluorides under mild conditions but also contributes to waste recycling.