Enhancing energy storage performance in flexible all-solid-state laser-induced graphene-based microsupercapacitors through the addition of carbon black and Prussian blue

Abstract

In this study, we present an efficient and scalable method for the stepwise modification of polyimide (PI)-based laser-induced graphene using environmentally friendly additives. The as-prepared composite materials were applied as flexible electrodes for high-performance all-solid-state microsupercapacitors (MSCs). The electrochemical deposition of carbon black (CB) microparticles and Prussian blue (PB) inorganic redox dye onto the laser-induced graphene electrode surface significantly enhanced the electrochemical performance of the devices. The areal capacitance of MSCs increased by 116 % after the addition of CB to the electrode composition, 201 % after the modification of the electrode surface with PB, and 325 % after incorporating both CB and PB (CB-PB). The exhibited capacitance values at an applied current density of 0.1 mA·cm−2 are equal to 27.6, 38.5 and 54.4 mF·cm−2 upon incorporating CB, PB and CB-PB, respectively. Furthermore, the use of a PVA/H2SO4 gel electrolyte led to a large stability electrochemical window of 3.0 V, resulting in an energy density as high as 68.1 μWh·cm−2 with a power density of 0.3 mW·cm−2 at 0.10 mA·cm−2. Additionally, the MSCs modified with CB-PB showed an excellent electrochemical stability, retaining over 95.8 % of their initial capacitance after 6000 galvanostatic charge-discharge cycles. Overall, this study presents a facile, convenient, and scalable approach for designing cost-effective and high-performance MSCs with a low-carbon footprint suitable for powering low-energy-consuming electronics.