Polythiophene/graphite fluoride composites cathode for high power and energy densities lithium primary batteries

• Polythiophene/graphite fluoride composites are synthesized by in situ polymerization.
• The conductive PTh coating reduces the charge transfer resistance of the cathode.
• The porous PTh morphology also improves the utilization of CFx.
• The content of PTh tunes the electrochemical performances of composites.
• 22.94 wt.% PTh/CFx composite delivers the power density of 4997 W kg−1 at 4C rate.

A series of polythiophene/graphite fluoride (PTh/CFx) composites have been synthesized by in situ polymerization of thiophene monomers on the surface of CFx. Transmission electron microscopy (TEM) demonstrates that 22.94 wt.% PTh/CFx is the suitable ratio for the composite due to the uniform and complete PTh coating on the surface of CFx particles. Electrochemical impedance spectra (EIS) measurements confirm that the coating of PTh decreases the charge transfer resistance of CFx cathode significantly. Conductive PTh serves as the conducting additive as well as the porous adsorbing agent, so the rate capability of PTh/CFx composites improves remarkably compared to pure CFx cathode. The amount of PTh coating affects the electrochemical performances of PTh/CFx composites, and the one containing 22.94 wt.% PTh can be discharged at high rate up to 4C delivering a maximum power density of 4997 W kg−1, associated with a high 1707 Wh kg−1 energy density.