Highly stable aqueous carbon-based conductive ink for screen-printed planar flexible micro-supercapacitor

In this study, we have successfully developed a series of low-cost, environmentally friendly, and highperformance carbon-based conductive inks with a three-dimensional micro-nano structure through a simple dispersion and ball-milling process, offering an array of desirable characteristics. Significantly, the carbon-based conductive inks remained stable even after a 30-day settling period. Furthermore, the conductive film, produced using screen printing techniques, demonstrated an impressive conductivity of 1.99 x 103 S/m. This remarkable conductivity highlights the ability of the films to consistently maintain a robust conductivity network, even when subjected to 5000 mechanical bending/releasing tests. Expanding on the success of our carbon-based conductive inks, we harnessed their potential in the production of all-solid-state flexible Micro-supercapacitors (MSCs) with an interdigital structure, utilizing screen-printing technology. The resulting MSCs exhibited outstanding performance metrics, including a notable areal energy density of 1.47 mu Wh cm-2 and an area power density of 0.2 mW cm-2. Moreover, these MSCs demonstrated remarkable cycle stability, retaining 96.3% of their capacitance after 20,000 cycles. Additionally, their excellent mechanical flexibility was evident as they experienced only a minor 2.98% capacitance degradation after undergoing 5000 bending/releasing cycles. These findings highlight the enormous potential of our work in facilitating the scalable production of wearable and portable electronic products.