Enhanced pseudocapacitive behaviour in laser-written graphene micro-supercapacitors decorated with nickel cobalt sulphide nanoparticles

The next generation of energy storage technologies requires enhanced fabrication techniques such as the use of CO2 infrared lasers to pattern micro-supercapacitor (MSC) electrodoes. This study reports direct-writen laser-induced graphene (LIG) micro-supercapacitors with electrodepositated NiCo2S4- nanoparticles on commercial polyimide sheets. X-ray photoelectron spectroscopy (XPS) combined with transmission electron microscopy (TEM) showed NiCo2S4 nanoparticles decorating the graphene, within a highly porous carbon-based electrode. The LIG/NiCo2S4 exhibited outstanding properties with a specific capacitance of 30.4 mF cm(-2) at 0.75 mA cm(-2) and an energy density of 16.9 mu Wh cm(-2) at a power density of 367.5 mu W cm(-2). High capacitance retention of 1.22-fold was measured after 5000 cycles of charge/discharge, and of similar to 90% when bent to 120 degrees angle. Here, it is demonstrated that surface decoration is an effective route in improving LIG MSC storage properties, and that the LIG/NiCo2S4 MSC is suitable for use in next generation of flexible and miniaturized portable devices.

Automated summary

This study demonstrates an enhanced fabrication technique using CO2 infrared lasers to pattern micro-supercapacitor electrodes. The direct-written laser-induced graphene (LIG) micro-supercapacitors with NiCo2S4 nanoparticles exhibited outstanding properties, including high specific capacitance and energy density, as well as excellent capacitance retention and flexibility. These findings suggest the potential use of LIG/NiCo2S4 MSC in the next generation of flexible and miniaturized portable devices.