High-Rate Performance of Fluorinated Carbon Material Doped by Phosphorus Species for Lithium-Fluorinated Carbon Battery

The lithium-fluorinated carbon (Li/CFx) battery possesses the highest energy density (2180 Wh kg(-1)) among all the primary lithium batteries. However, the poor electronic conductivity of the fluorinated carbon (CFx) material sets a limit on its rate discharge capability, confining its practical application. In this article, a doping strategy at a mild anneal condition is developed to synthesize the phosphorus species-doped CFx materials (P-CFx) for Li/CFx batteries. Compared to the commonly used methods, this eco-friendly, and simple doping method does not involve washing, centrifugation, and filtration processes. Characterization using X-Ray diffraction, high-resolution transmission electron microscope, and X-Ray photoelectron spectroscopy confirms the successful doping and the structure of the P-CFx. Density functional theory calculations and characterization results demonstrate that phosphorus species doping can alter microstructure and induce charge redistribution to improve electronic and ionic conductivity. Therefore, the Li/P-CFx battery possesses a high specific capacity and an excellent rate capability, shown by a high discharge capacity of 810 mAh g(-1) with a voltage plateau of 2.53 V at 0.1 C. Extraordinarily, a discharge capacity of 597 mAh g(-1) with a voltage plateau of 1.90 V at 20 C has been achieved as well as a high power density of 34 048 W kg(-1).