Optimization of MXene/CNT free-standing composite electrodes for enhanced electrochemical performance in symmetric supercapacitors

The integration of one-dimensional (1D) and two-dimensional (2D) materials into three-dimensional (3D) structures shows great potential for improving energy storage. This study investigates the optimization of interlayer spacing in MXene structures by incorporating conductive materials. Free-standing Ti3C2Tx MXene and carbon nanotube (CNT) composite electrodes were fabricated via vacuum filtration, with CNT weight ratios of 10 %, 20 %, and 30 %. The MXene/CNT10 (MX1) composite exhibited superior electrochemical performance, with a specific capacitance of 254 F g⁻1 and remarkable durability, retaining 101.2 % of its initial capacitance after 10,000 cycles. A symmetric supercapacitor (SSC) using the MX1 electrode achieved a stable voltage window of 0–1.2 V, a specific capacitance of 70.1 F g⁻¹, and retained 85 % of its capacitance after 5000 cycles. With an energy density of 14.1 Wh kg⁻1 and a power density of 13.9 kW kg⁻1, MXene/CNT composites demonstrate significant potential for advanced energy storage applications. © 2025 Elsevier Ltd