Electrodeposition on laser induced graphene dual conductive substrate as a free-standing electrode for asymmetric supercapacitors

Herein, combing laser-induced graphene (LIG) obtained by laser scribing on polyethersulfone (PES) films with carbon cloth (CC) forming novel dual conductive networks can cause the well-designed electrode materials possessing strong electric conductivity in favor of electron transferring. The free-standing NiCo/L-CC@PES-IG or Fe/L-CC@PES-IG have been prepared through laser scribing and electrodeposition processes at mild conditions. Fe/L-CC@PES-IG exhibits a high areal specific capacitance of 1544 mF cm⁻² at a current density of 1 mA cm⁻², which matches well with NiCo/L-CC@PES-IG (1840 mF cm⁻²). It is worth mentioning that the capacitance retention of NiCo/L-CC@PES-IG can reach 80 % at 10 mA cm⁻², ca. 16 times that of NiCo/L-CC-IG (only 5 %) just adding small amount PES, which indicate that the dual conductive network synergistic effect of the external conductive graphene and the internal CC. The asymmetric supercapacitor (ASC) device is constructed using NiCo/L-CC@PES-IG as a positive electrode and Fe/L-CC@PES-IG as a negative electrode, which delivers a high areal energy density of 381 μWh cm⁻² at the areal power density of 825.8 μW cm⁻². This work provides a unique insight into the design of hybrid supercapacitor assembled with matching positive and negative electrodes, which will achieve the desired superhigh performance.