Fabrication of Adhesive Planar-Type Graphite-Based Microsupercapacitors

Wearable and portable electronic devices have garnered significant interest, and the development of microsupercapacitors (MSCs) using flexible adhesive tapes and low-cost materials is crucial to expanding their applications in flexible electronics. In this study, we present an adhesive, flexible, planar-type graphite-based microsupercapacitor (PMSC) fabricated using the blade coating method, where a graphite-carbon black paste was applied onto adhesive tape. An alginate-based gel electrolyte was prepared by adding 1 M KOH to alginic acid in water to form a biodegradable electrolyte. PMSCs exhibited outstanding electrochemical performance, achieving the highest reported volumetric specific capacitance of 213.2 F cm^–3, areal specific capacitance of 639.5 mF cm^–2, energy density of 7.4 mW h cm^–3, (1.11 mW h cm^–2), and power density of 266.5 mW cm^–3 (39.98 mW cm^–2) among all carbon-based PMSCs. Furthermore, they demonstrated excellent mechanical stability under various deformations, including twisting, parallel bending, and vertical bending relative to the electrode direction, maintaining a capacitance retention of over 95%. These results highlight the potential of our PMSCs for use in next-generation flexible and wearable energy storage devices.