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The high energy density of fluorinated graphite (CF x) based lithium primary battery has aroused tremendous attention. However, the nonconductive CF x always induces high interface impedance and low power density. Herein, the carbon conductive network is generated by thermal treatment of resorcinol/formaldehyde (RF) resin on CF x and RF resin spheres (RF RSs), a conductive carbon layer coats on CF x surface, the electrical conductivity of CF x is improved. The oxygen functional groups in incomplete carbonized RF RSs also dedicate to the electrochemical performance of CF x. When different mass ratios of CF x /RF RSs are employed, the cathodes exhibit improved rate performance and voltage plateaus, and the initial voltage delays observed in CF x are significantly reduced. Notably, CF x /RF RSs−13 cathode delivers an impressive discharge capacity of 843.8 mAh g−1 with a voltage plateau of 2.68 V at 10 mA g−1. This leads to the maximum energy density of 2174.9 Wh kg−1 and a peak power density of 18600 W kg−1. Additionally, CF x /RF RSs−13 cathode demonstrates commendable electrochemical stability across a wide temperature spectrum (−20–70 °C). Given these superior electrochemical attributes, the CF x /RF RSs combination holds significant promise for deployment in high-power devices and for standard operations under extreme temperature conditions. • Carbon conductive network is induced by heat treatment of RF resin on CF x and RF RSs. • Oxygen functional groups in RF RSs also make for electrochemical performance of CF x. • CF x /RF RSs−13 gives peak energy and power densities of 2174.9 Wh kg−1, 18600 W kg−1. • CF x /RF RSs−13 demonstrates commendable electrochemical stability from −20 to 70 °C. [ABSTRACT FROM AUTHOR]

Herein, we suggest a new way to improve the cycling stability of the lithium-metal battery by using a separator coated by carbon monofluoride (CF x). CF x has been used as a cathode material for a lithium primary battery and is converted to LiF and carbon during the discharge process. The CF x -coated separator with 5 μm thickness is obtained by casting a CF x -containing slurry on a bare polyethylene separator and the CF x -coated separator is characterized in a LiCoO 2 (LCO) // Li cell. The CF x -coated separator enables a better cycling stability up to 200 cycles than the bare separator due to its dual functions: 1) capturing cobalt ions dissolved from the LCO cathode and 2) formation of a thin and stable SEI layer containing LiF on the lithium metal anode. Employment of the CF x -coated separator also leads to much suppressed dendritic growth of lithium and stable interfacial resistance during the cycle. Unlabelled Image • We prepare a separator coated with carbon monofluoride (CF x) for Li-metal battery. • The CF x on the separator is converted to LiF and carbon in the 1st discharge process. • The cobalt ions dissolved from the LCO cathode are captured by the CF x coating layer. • A thin and stable SEI layer containing LiF is formed on the lithium metal anode. • The bifunctions of the CF x -coating enables good cycling stability of a LCO//Li cell. [ABSTRACT FROM AUTHOR]

A new electrochemical method is demonstrated for the synthesis of carbon-metal fluoride nanocomposites at room temperature. • A new electrochemical method is demonstrated for the synthesis of C-MF x at RT. • Electrochemical intercalation of transition metal ions into graphite fluoride (CF x). • C-FeF 2 , C-NiF 2 was synthesized by electrochemical intercalation of Fe2+, Ni2+ in CF x. • Electrochemical method for the synthesis of carbon-metal fluoride nanocomposites. Herein we have demonstrated an electrochemical method for the synthesis of carbon-metal fluoride nanocomposites (CMFNCs). Electrochemical intercalation of transition metal ions into graphite fluoride (CF x) resulted in the formation of CMFNCs. As a proof-of-concept, we have synthesized C-FeF 2 and C-NiF 2 nanocomposites by the electrochemical intercalation of Fe2+ and Ni2+ into CF x from corresponding non-aqueous electrolytes. The C-FeF 2 and C-NiF 2 nanocomposites synthesized by this method showed high reversible capacity and cycling stability compared to chemically synthesized analogs as cathode materials for lithium batteries. The reversible capacity of chemically synthesized C-FeF 2 is 181 mAh g−1, whereas electrochemically synthesized material is 349 mAh g−1 after 20 cycles. The better cycling performance of electrochemically synthesized C-FeF 2 was attributed to the homogeneous distribution of FeF 2 nanoparticles within the carbon matrix enabled by the electrochemical intercalation of Fe2+. The electrochemical method described here is emission-free, cost-effective, occurs at room temperature, and extendable to the synthesis of several other CMFNCs. Moreover, it might provide new avenues for the synthesis of advanced functional materials. [ABSTRACT FROM AUTHOR]