Laser‐Induced Formation of Fine Porous Graphitic Carbon for Eco‐Friendly Supercapacitors

An electric double‐layer capacitor (EDLC), which is one of the pivotal energy storage devices, provides rapid charge–discharge capabilities and an extended cycle life. Areal capacitance, a key indicator of EDLC performance, increases with the specific surface area of its electrodes. This study demonstrates a method for significantly increasing the specific surface area in the laser‐induced graphitization of biodegradable polymers by incorporating NaHCO 3 into the composite sheet, generating not only microscale pores but also a large number of nanoscale fine pores. Furthermore, it shows that using these structures as EDLC electrodes leads to a substantial increase in areal capacitance. An increase in the number of fine pores formed in the structure and a corresponding rise in the areal capacitance of the fabricated EDLC are observed with the increase in the NaHCO 3 weight ratio. Notably, the composite sheets are composed of natural‐derived, biodegradable materials, while NaHCO 3 is known for its low corrosivity and biotoxicity. The proposed method thus offers a pathway for fabricating energy storage devices with minimal environmental impact, ensuring their eco‐friendly disposal post‐use.