Fluorinated Two-Dimensional Carbon Sheets with LiF-Rich Interfaces for High-Performance Lithium-Ion Battery Anodes

Abstract

Graphite anodes have limited current density performance, which restricts their application in fast-charging lithium-ion batteries (LIBs). In this study, fluorinated pitch-derived carbon sheets (FPCS) were synthesized from petroleum pitch using a NaCl template followed by NF₃ plasma treatment. The NaCl template process generated thin, two-dimensional (2D) carbon sheets with wide interlayer spacing, shortening the diffusion path for lithium-ions. Subsequent NF₃ plasma treatment introduced fluorine functional groups, forming semi-ionic C–F bonds, which promoted the formation of a LiF-rich solid electrolyte interphase, enhancing interfacial stability and ion transport. As a result, the FPCS exhibited a capacity of 210 mAh/g at 5 A/g, representing a 37% increase over the raw sample. Furthermore, it demonstrated excellent cycling stability, maintaining a capacity of 190 mAh/g, even after 250 cycles at a current density of 1 A/g. These results demonstrate that the synergistic effect of template-assisted 2D structure and plasma fluorination enhances ion transport and interfacial stability, presenting a practical strategy for high-rate LIBs.