Plasma-Induced CoF₂ Formation and Carbon Coating for Bond Adjustment and Polarization Inhibition in High-Rate Li/CF_<i>x</i> Batteries

Fluorinated carbon (CF_<i>x</i>) contains strong covalent C-F bonds, leading to severe electrochemical polarization in Li/CF_<i>x</i> batteries with a limited rate performance. Herein, a synergy technology was developed to prepare a CF_<i>x</i>/CoF₂/C composite for a high-rate Li/CF_<i>x</i> battery combining bond adjustment and polarization inhibition effects. Typically, the CF_<i>x</i>/CoF₂/C composite in situ generated coupling with a mixed-liquid phase reaction and C₂H₂/Ar plasma-inducing technology. In detail, the intermediate/CF_<i>x</i> 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 CF_<i>x</i>. The charge transfer resistance of the CF_<i>x</i>/CoF₂/C composite is reduced from 267.9 to 51.7 Ω compared with raw CF_<i>x</i>. The energy density of the CF_<i>x</i>/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 CF_<i>x</i> by plasma-inducing technology, synergistically achieving CF_<i>x</i> bond adjustment and polarization inhibition to address high-rate batteries.