3D‐Printed Crosslinked Nanocellulose‐MXene Hydrogels and Aerogels with High Strength and Conductivity

Extrusion-based 3D-printing is a promising manufacturing method because it can integrate various nanomaterials, including highly conductive MXenes. Nevertheless, the fabrication of both wet and dry stable 3D-printed structures with MXene has remained challenging due to the difficulty in forming mechanically stable, crosslinked networks with the required rheological properties. In this work, a MXene ink formulation incorporating cellulose nanofibers (CNFs) as rheology modifiers is developed, enhancing structural integrity and enabling a one-step freeze-induced crosslinking process to produce lightweight, porous structures. The 3D-printed structures exhibit remarkable mechanical strength, supporting up to 10,000 times their own weight, while maintaining a conductivity of over 195 S m^-1. Additionally, they demonstrate a specific capacitance of 240 F g^-1 at 5 mV s^-1, highlighting their potential for applications in advanced iontronic devices. A fully 3D-printed supercapacitor concept is showcased in two distinct configurations: in-plane and stacked; demonstrating their structural integrity and electrochemical stability in aqueous environments.