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Abstract:
Laser-induced graphene (LIG) offers a promising platform for lithium-ion battery electrodes due to its high conductivity and porous three-dimensional architecture; however, its limited electrochemical activity restricts practical application. This study presents poly(3,4-ethylenedioxythiophene) -modified LIG cathodes prepared via two distinct polymerization strategies. In the first approach, 3,4-ethylenedioxythiophene monomers are polymerized in solution with an oxidant before deposition onto LIG. In the second approach, the monomer is first deposited onto the LIG surface, followed by separate oxidant introduction to confine polymerization directly at the electrode interface. Structural characterization confirms successful polymer incorporation while preserving the porous LIG framework. The surface-confined approach yields more uniform polymer distribution and stronger polymer-substrate interaction, as evidenced by enhanced π–π coupling observed in Raman spectra. Electrochemical evaluation reveals that polymer loading significantly affects performance, with an optimal monomer volume providing balanced coverage without pore blockage. Electrodes prepared via surface-confined polymerization deliver a specific capacity of approximately 170 mAh g−1 at 0.003 A g−1, representing a tenfold improvement over pristine LIG, and retain 85% capacity after 100 cycles. Electrochemical impedance spectroscopy confirms reduced charge-transfer resistance and improved ion diffusion for this approach. These findings establish poly(3,4-ethylenedioxythiophene) -modified LIG as a promising metal-free cathode material for flexible lithium-ion batteries.

Keywords:
Energy storage, Laser-induced graphene, Polymer coating, Plasma treatment, Lithium-ion battery