Plasma-Induced CoF2 Formation and Carbon Coating for Bond Adjustment and Polarization Inhibition in High-Rate Li/CFx Batteries

Fluorinated carbon (CFx) contains strong covalent C-F bonds, leading to severe electrochemical polarization in Li/CFx batteries with a limited rate performance. Herein, a synergy technology was developed to prepare a CFx/CoF2/C composite for a high-rate Li/CFx battery combining bond adjustment and polarization inhibition effects. Typically, the CFx/CoF2/C composite in situ generated coupling with a mixed-liquid phase reaction and C2H2/Ar plasma-inducing technology. In detail, the intermediate/CFx mixtures were prepared by mixing Co(NO3)2 as a cobalt source and NaOH as a precipitant, immediately following the C2H2/Ar plasma treatment. The introduction of CoF2 favors the C2H2 decomposition into the carbon layer deposition during the plasma bombardment. Furthermore, the as-designed composite possesses rich semi-ionic C-F bonds, which suppress the polarization of CFx. The charge transfer resistance of the CFx/CoF2/C composite is reduced from 267.9 to 51.7 Ω compared with raw CFx. The energy density of the CFx/CoF2/C cathode increased to 1.89 times with a value as high as 1185.65 Wh/kg at 15 C. This novel cathode combines energetic CoF2 and a conductive carbon layer to modify CFx by plasma-inducing technology, synergistically achieving CFx bond adjustment and polarization inhibition to address high-rate batteries.