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.