Abstract
Extrusion-based 3D printing, enables programming of device geometries not achievable with other manufacturing techniques. The fabrication of miniaturized energy storage devices is in increasing demand to enable energy autonomy in on-chip technologies. Here, we demonstrate a new fabrication route of such devices, by robocasting viscoelastic inks of atomically thin transition metal dichalcogenide sheets. We have formulated inks based on the direct exfoliation of TMD nanosheets, suspended in a hydrogel-carrier environment. By tailoring the rheological properties of the ink to aid the intrinsic shear-inducing extrusion flow, we have demonstrated 3D printed micro electrodes for symmetric supercapacitors. With the rational design of 3D electrodes, exposed 2D nanosheets unveil rapid surface non-faradaic electrostatic charges and continuous charge transfer reactions, which translates into a higher capacitance and rate capability. The highlights in this work lead to an important leap for TMDs-based 3D printed energy storage devices.