A 3D-printed fully biocompatible supercapacitor

Abstract

A fully biocompatible supercapacitor was fabricated utilizing dopamine-grafted activated carbon-based (DPBAC) electrode material along with a choline chloride–urea-based eco-friendly Reline deep eutectic solvent electrolyte. The current collector (graphite ink), electrode (DPBAC ink), and electrolyte (Reline) were 3D printed using the optimized printing parameters tailored specifically for the Piezo jet dispenser printing tool. Dopamine was grafted on commercially available (YP-80 F) bare activated carbon (BAC) using the π–π stacking method. Thermogravimetric analysis, Raman spectroscopy, Brunauer–Emmett–Teller method and X-ray photoelectron spectroscopy results confirmed the grafting of dopamine on BAC. 3D printed devices (size of 50 mm × 50 mm × 0.5 mm) were fabricated using DPBAC and BAC-based electrode materials to study the electrochemical performance. The DPBAC supercapacitor displayed a specific capacitance of 39 F g⁻¹ which was comparatively higher than that of BAC (23 F g⁻¹) at a current density of 0.2 A g⁻¹, demonstrating the contribution of the redox reaction of the grafted dopamine molecule. The developed 3D-printed fully biocompatible supercapacitors (3DPBSC) demonstrate an outstanding specific capacitance of 96 F g⁻¹ at a scan rate of 1 mV s⁻¹ which surpasses the previously reported state-of-the-art performance (25.6 F g⁻¹ at a scan rate of 1 mV s⁻¹ for 1.2 V for fully 3D printed and disposable paper supercapacitors). Moreover, 3DPBSC exhibited a maximum energy density of 22 W h kg⁻¹ at a power density of 1835 W kg⁻¹ within a device voltage range from 0 to 2.0 V. These results highlight the promising potential of the fabricated 3DPBSC as flexible and sustainable supercapacitors for applications in low-power wireless sensors.