Defective nano-structure regulating C-F bond for lithium/fluorinated carbon batteries with dual high-performance

Abstract

Lithium/fluorinated carbon (Li/CFx) batteries show significant potential owing to high energy density and long-term storage performance. Restricted to the mutual restriction of F/C ratio and conductivity, the high energy density and power density cannot be achieved simultaneously. Herein, fluorinated honeycomb N-doped graphene (F-HNG) with conductive C-F bond was regulated by structural and heteroatomic defects, which was fabricated by nanoscale etching, NH3 treatment and gas phase fluorination. The unique pore provided smooth channels and storage sites for Li+ migration, while N atom with more electronegativity further regulated the charge distribution of the carbon skeleton. F-HNG delivered dual excellent electrochemical performance of a maximum energy density of 2595.47 Wh kg-1, associated with the unprecedented power density of 73.203 kW kg-1 at an ultrahigh rate of 50 C. Li/F-HNG pouch cell achieved an energy density of 707.52 Wh kg-1 with a mass loading of 10–15 mg cm-2 and reduced the heat release and battery swelling. In-depth density functional theory (DFT) calculations revealed that synergistic effect of porosity and N-doping regulated its C-F bond configuration, thermodynamic parameters, and ion diffusion pathway. This work indicates that nano-defect engineering and heteroatomic doping provide innovative possible directions for the design of CFx cathodes with dual superior performance.