2D-Supported Vertical MXenes for Ultrafast Filtering with Ultralow Inductance

Filtering supercapacitors (SCs) are promising for miniaturized power filter electronics due to their high capacitance and robust high-power performance. However, their adoption is limited by a poor low-frequency response in planar porous electrodes, causing mismatched operating frequencies and overheating risks. To address this, we develop MXene-based SCs using a novel vitamin C-assisted solution-thermal method to assemble Ti₃C₂T_<i>x</i> MXenes into 2D-supported vertical structures, enhancing the dynamic response for linear filtering. These SCs achieve an ultrafast frequency response of 13.8 kHz at a phase angle of -45°, with electric inductance 1/2000 that of commercial aluminum electrolytic capacitors (AECs). They exhibit high areal and volumetric capacitances and effectively smooth random AC waveforms into stable DC signals. Their practicality is demonstrated by replacing bulky AECs and parallel capacitors in a Bluetooth audio amplifier, delivering wireless audio playback without tone quality loss and highlighting their transformative potential for next-generation electronics.