Fluorophosphate compounds are an important class of cathode materials; however, the one-step synthesis of phase-pure fluorophosphate compounds in a well-controlled manner remains challenging owing to the facile volatilization of fluorine during heat treatment. Herein, the rapid, facile, and scalable preparation of phase-pure fluorophosphates (e.g. KVPO₄F) was successfully realized via a one-step solid-state reaction through the addition of PVDF, which served as an effective fluorine-compensating, vanadium-reducing, and in situ carbon-coating agent. In-depth mechanistic study showed that carbene (:CH₂) generated upon PVDF decomposition could be easily recombined to form a ˙CH₂(CH₂)_nCH₂˙ alkyl biradical, and both were able to catalyze C–F bond breakage in fluorocarbon gases (C₂F₄) and therefore plays a pivotal role in promoting the formation of phase-pure fluorophosphate. The resultant cathode enabled a superior potassium-storage capability, including high specific capacity, excellent rate capability, and good cycling stability. The generality of the as-proposed synthetic strategy was also validated through the successful preparation of other fluorophosphate compounds.

中文翻译：

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卡宾催化合成氟磷酸盐阴极


氟磷酸盐化合物是一类重要的正极材料；然而，由于氟在热处理过程中容易挥发，以良好控制的方式一步合成相纯氟磷酸盐化合物仍然具有挑战性。在此，通过添加PVDF的一步固相反应成功实现了相纯氟磷酸盐（例如KVPO ₄ F）的快速、简便且可规模化的制备，PVDF是一种有效的氟补偿剂、钒还原剂、原位碳包覆剂。深入的机理研究表明，PVDF分解产生的卡宾(:CH ₂ )可以很容易地重新组合形成˙CH ₂ (CH ₂ ) < b4> CH ₂ ˙ 烷基双自由基，两者都能催化氟碳气体中的 C-F 键断裂 (C ₂ F ₄ )因此在促进相纯氟磷酸盐的形成方面起着关键作用。所得正极具有优异的储钾能力，包括高比容量、优异的倍率性能和良好的循环稳定性。通过成功制备其他氟磷酸盐化合物也验证了所提出的合成策略的通用性。