East Asian Calligraphy Black Ink-Coated Paper as Flexible Conducting Electrode for Supercapacitor

East Asian calligraphy black ink (hereafter called simply “black ink”) is used to fabricate flexible conducting chromatography paper electrode by a simple and low-cost method. The black ink-coated paper was characterized by scanning electron microscopy, surface profiler, water contact angle measurement, electrical resistance measurement, X-ray photoelectron spectroscopy, and X-ray diffraction. The hydrophilicity slightly decreased after black ink coating but still provided good adhesion to the follow-up reduced graphene oxide/polyaniline/chitosan slurry coating for fabricating supercapacitor electrodes. A 1000-cycle repeated bending test with a bending radius of 5 mm revealed good conductance retention. Instrumental analyses indicated that the carbon black in the black ink was the main contributor to the electrical conductance. The supercapacitor with black-ink-coated paper electrodes exhibited an areal specific capacitance of up to 179.08 mF cm −2 and coulomb efficiency of 80%. This confirmed that the black-ink-coated paper electrode could be feasibly applied to a supercapacitor. This black-ink-coated paper can be easily fabricated in resource-limited settings, and it provides new possibilities for the use of paper-based electrodes in flexible electronics.