3D Printing of Porous Nitrogen-Doped Ti3C2 MXene Scaffolds for High-Performance Sodium-Ion Hybrid Capacitors

3D printing technology has stimulated a burgeoning interest to fabricate customized architectures in a facile and scalable manner targeting wide ranged energy storage applications. Nevertheless, 3D-printed hybrid capacitor devices synergizing favorable energy/power density have not yet been explored thus far. Herein, we demonstrate a 3D-printed sodium-ion hybrid capacitor (SIC) based on nitrogen-doped MXene (N-Ti₃C₂T_x) anode and activated carbon cathode. N-Ti₃C₂T_x affording a well-defined porous structure and uniform nitrogen doping can be obtained via a sacrificial template method. Thus-formulated ink can be directly printed to form electrode architecture without the request of a conventional current collector. The 3D-printed SICs, with a large areal mass loading up to 15.2 mg cm^-2, can harvest an areal energy/power density of 1.18 mWh cm^-2/40.15 mW cm^-2, outperforming the state-of-the-art 3D-printed energy storage devices. Furthermore, our SIC also achieves a gravimetric energy/power density of 101.6 Wh kg^-1/3269 W kg^-1. This work demonstrates that the 3D printing technology is versatile enough to construct emerging energy storage systems reconciling high energy and power density.