Laser Processing of Highly Conductive Graphene Electrodes for Micro-Supercapacitors

Micro-supercapacitors (MSCs) have become promising micro-storage devices in the field of microelectronics due to their advantages of small size, high power density, and excellent cycling stability. In this work, a composite laser processing technique was reported to convert cyanate ester resin into highly conductive graphene (LIG) films using CO
2
and fiber lasers in ambient air, respectively. Under the CO
2
laser pyrolysis of resin and subsequent fiber laser annealing, the resulting LIG film exhibits an ultra-low sheet resistance (1.67 Ω per square), which is one order of magnitude lower than that of polyimide (PI)-induced LIG films, indicating the advance of the composite laser processing technique. The effect of substrates with two thermal conductivities on the morphology, sheet resistance and electrochemical performance of the LIG films was also investigated. Benefiting from the excellent thermal conductivity of metal substrate, LIG/Ti-MSCs with titanium substrate provide an areal capacitance of 26.4 mF/cm
²
at a scan rate of 5 mV/s, which is higher than that of LIG/PI-MSCs with PI substrate (~17.6 mF/cm
²
) under the same conditions.