Modulating C─F Bonds of Fluorinated Graphite via Compounding Graphene Oxide for High-Energy/Power Lithium Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Lithium/fluorinated carbon (Li/CF_x) primary batteries are crucial for aerospace and military applications.
• Achieving a balance between high energy density and power density in Li/CF_x batteries is challenging due to the material's inherent structure and strong carbon-fluorine bonds.

Purpose of the Study:

• To develop an improved composite material for Li/CF_x batteries.
• To overcome the limitations of traditional Li/CF_x materials by enhancing energy and power density.

Main Methods:

• A liquid-phase exfoliation strategy was employed to modify fluorinated graphite (FG) with graphene oxide (GO).
• The optimized GO-FG composite was characterized for its structural and electrochemical properties.
• Flexible pouch cells were assembled using the developed composite for performance evaluation.

Main Results:

• The optimized GO-FG composite exhibited an exfoliated layer structure and modulated carbon-fluorine bonds.
• A maximum energy density of 2740.00 Wh kg^-1 was achieved at 0.01 C.
• Ultra-high power densities of 84.88 kW kg^-1 (at 50 C) and 119.33 kW kg^-1 (at 80 C) were demonstrated.
• Flexible pouch cells delivered capacities of 1.06 Ah (at 0.1 C) and 0.96 Ah (at 5 C).

Conclusions:

• The compounding of reduced graphene oxide with fluorinated graphite significantly modulates the carbon-fluorine bond strength.
• In situ exfoliation opens the layer structure of CF_x, creating a conductive framework.
• These modifications synergistically enhance reaction kinetics, leading to improved performance in Li/CF_x batteries.