Flexible Micro-Supercapacitors with Enhanced Energy Density Utilizing Flash Lamp Annealed Graphene-Carbon Nanotube Composite Electrodes

Abstract

As demand for micro-power sources grows, micro-supercapacitors (MSCs) have become critical for miniaturized devices, offering robust electrochemical energy storage. However, the challenge remains to develop a simple, scalable fabrication method that achieves both high energy and power densities. In this study, we present a refined approach to fabricating MSCs with 3D interconnected graphene/carbon nanotube (CNT) composite electrodes. Our method combines flash lamp annealing (FLA) and laser ablation, where FLA converts graphene oxide (GO) and CNT composite films into 3D-structured graphene/CNT electrodes, and laser ablation precisely patterns them into interdigitated designs. This dual-process technique produces MSCs with exceptional electrochemical performance, including an impressive areal capacitance of 26.11 mF/cm² and a volumetric capacitance of 31.88 F/cm³. These devices also achieve energy densities of 3.72 μWh/cm² and 4.43 mWh/cm³, maintaining 97 % of their initial capacitance under extreme bending, demonstrating outstanding mechanical flexibility and durability. Furthermore, the scalability of this method was validated by configuring MSCs in series and parallel, achieving enhanced voltage and current outputs without additional interconnections. Overall, the integration of FLA and laser ablation holds significant promise for advancing the performance and scalability of micro-sized energy storage devices, addressing the growing need for efficient, flexible, and high-capacity micro-power sources.