Development of flexible boron-doped laser-induced graphene with enhanced porosity for high-performing symmetric supercapacitor device

This study demonstrates a facile method for boron-doped laser-induced graphene (BLIG) synthesis on a polyimide sheet via CO 2 laser and boric acid (H 3 BO 3 ) as the source of dopant. Initially, LIG was dispersed with H 3 BO 3 having different doping concentrations of 0.5, 1.0, 1.5, and 2.0 mg/cm 2 to prepare four samples named BLIG-1, 2, 3, and 4, respectively, followed by a second laser irradiation. This work investigates the effect of different boron concentrations on the structural and electrochemical properties of the LIG. The Raman analysis validated the fabrication of multilayer LIG, and peak at 26.05° in XRD corresponded to the graphene’s (002) plane with the interplanar spacing of 3.41 Å. The boron doping was further confirmed through the presence of the BC 3 bond in XPS, and a porous structure was confirmed through the SEM image with a high specific surface area of 325.2 m 2 /g, calculated from BET. The electrochemical performance was optimized for the BLIG electrodes using a 3-electrode system. The optimized BLIG-1 electrode delivered areal capacitance (C s ) of 92.2 and 132.7 mF/cm 2 at 2 mV/s scan rate, along with an energy density (E d ) of 2.4 and 8.2 µWh/cm 2 on PI sheet and graphitic paper, respectively. The symmetric Swagelok SC exhibited the C s of 19.8 mF/cm 2 at 0.017 mA/cm 2 and E d of 1.37 µWh/cm 2 with a power density (P d ) of 8.5 µW/cm 2 . Additionally, a pouch cell device demonstrates the C s of 9.4 mF/cm 2 at 2 mV/s, having outstanding stability, retaining 99.31% after 10,000 cycles, demonstrating remarkable energy storage capabilities. This research highlights the promising role of BLIG in energy storage applications.