High-Power-Density, High-Energy-Density Fluorinated Graphene for Primary Lithium Batteries

Li/CF(x) is one of the highest-energy-density primary batteries; however, poor rate capability hinders its practical applications in high-power devices. Here we report a preparation of fluorinated graphene (GF(x)) with superior performance through a direct gas fluorination method. We find that the so-called “semi-ionic” C-F bond content in all C-F bonds presents a more critical impact on rate performance of the GF(x) in comparison with sp(2) C content in the GF(x), morphology, structure, and specific surface area of the materials. The rate capability remains excellent before the semi-ionic C-F bond proportion in the GF(x) decreases. Thus, by optimizing semi-ionic C-F content in our GF(x), we obtain the optimal x of 0.8, with which the GF(0.8) exhibits a very high energy density of 1,073 Wh kg(−1) and an excellent power density of 21,460 W kg(−1) at a high current density of 10 A g(−1). More importantly, our approach opens a new avenue to obtain fluorinated carbon with high energy densities without compromising high power densities.