Li/CF_x batteries are an essential energy source for advancing smart medicine and deep-space exploration, yet increasing their energy density is crucial for large-scale applications. However, CF_x cathode development is hindered due to the voltage–capacity trade-off when the actual synthesis is considered. To solve this problem, the mechanism of fluorination and key factors that affect the fluorine pattern must be determined. In this study, we propose a diffusion-controlled fluorination mechanism, and the critical role of the carbon source structure in the fluorination kinetics and fluorine pattern of the formed CF_x is revealed. As a proof-of-concept, we prepared a series of hierarchical porous carbons (HPCs) and promoted fluorination kinetics with their well-developed hierarchical pore structure, achieving a high fluorine content from full interior fluorination and an altered fluorine pattern. In addition, the low fluorination temperature enabled by HPCs helped preserve the skeleton structure and improve the conductivity, resulting in an excellent maximum energy density of 2902.45 W h kg⁻¹ (0.05C) and power density of 74.837 kW kg⁻¹ at 50C. Orthogonal experiments, which facilitated the tailoring of battery performance, demonstrated the synergistic effect of the carbon source and fluorination temperature for the first time. This study provides theoretical and practical guidance for designing and implementing CF_x cathodes for ultrahigh-energy-density Li/CF_x batteries, and the results pave the way for various large-scale applications of Li/CF_x batteries in the future.

中文翻译：

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阐明碳源对氟化动力学和 CFx 结构的影响，以定制 Li/CFx 的能量密度


Li/CF_x 电池是推进智能医疗和深空探索的重要能源，但提高其能量密度对于大规模应用至关重要。然而，在考虑实际合成时，由于电压-容量权衡，CF_x 阴极的发展受到阻碍。为了解决这个问题，必须确定氟化机制和影响氟模式的关键因素。在这项研究中，我们提出了一种扩散控制的氟化机制，并揭示了碳源结构在形成的 CF_x 的氟化动力学和氟模式中的关键作用。作为概念验证，我们制备了一系列多级多孔碳 （HPC），并利用其发达的多级孔结构促进了氟化动力学，通过完全内部氟化和改变的氟模式实现了高氟含量。此外，HPC 实现的低氟化温度有助于保持骨架结构并提高导电性，从而在 50C 下产生 2902.45 W h ^kg-1 （0.05C） 的出色最大能量密度和 74.837 kW ^kg-1 的功率密度。正交实验促进了电池性能的定制，首次证明了碳源和氟化温度的协同效应。 本研究为超高能量密度 Li/CF_x 电池的 CF_x 正极的设计和实现提供了理论和实践指导，结果为 Li/CF_x 电池未来各种大规模应用铺平了道路。