Fluorinated laser-induced graphene towards high performance Zn-ion hybrid supercapacitors

Laser induced graphene (LIG) based micro-supercapacitors (LIG-MSCs) have sprung up rapidly in recent years, driven by the huge demand for flexible energy storage devices. However, the low energy density arising from the limited specific surface area and few active sites of LIG-MSCs greatly limits their practical application. In this context, this work proposes an asymmetric construction of Zn@FLIG//FLIG electrodes using fluorinated polyimide (FPI) as the substrate. A more porous structure of FLIG can be achieved by the decomposition of fluorine-containing groups into gaseous products during the laser irradiation process. The interconnected porous structure of FILG further acts as an ideal substrate for the uniform electrodeposition of Zn nanosheets , which also enhances the energy density of the MSC. The areal capacitance of the FLIG based zinc-ion hybrid supercapacitor (FLIG-ZHMSC) was 42.32 mF·cm −2 , more than 15 times of the commercial LIG based ZHMSC (CLIG-ZHMSC) (2.73 mF·cm −2 ). The energy density of FLIG-ZHMSC has been significantly increased to 15.1 μWh·cm −2 , compared to 0.97 μWh·cm −2 for CLIG-ZHMSC. FLIG-ZHMSC was also able to retain 79.4% of its initial capacitance after 7000 cycles at a current density of 1 mA·cm −2 . Meanwhile, FLIG-ZHMSC works stably at different bending conditions, holding a great application prospect for wearable and intelligent device applications.