Engineering multiwalled carbon nanotube modified titanium carbide MXene nanocomposites for flexible symmetric supercapacitors in printed electronics

Abstract

MXene-based micro-supercapacitors (MSCs) are promising power sources for wearable electronics and distributed IoT systems, yet their scalability is limited by MXene restacking and complex fabrication protocols. Here, we present the development and optimization of delaminated Ti₃C₂T_x MXene (D-MXene)/multi-walled carbon nanotube (MWCNT) composite electrodes with enhanced electrochemical performance. The incorporation of 20 wt% MWCNTs effectively suppresses MXene restacking, facilitating improved ion transport and structural integrity. The optimized D-MXene/MWCNT composite electrode (MC-20) exhibits a high specific capacitance of 645 F g⁻¹ corresponds to galvanostatic charge discharge cycles (GCD) at a current density of 1 A g⁻¹, with 88% retention after 10 000 cycles. To demonstrate the practical utility of the optimized material, a flexible printed micro-supercapacitor (MSC) was fabricated using a D-MXene/MWCNT/PEDOT:PSS composite following a previously established printing protocol. The device exhibits an areal capacitance of 53 mF cm⁻² at 0.1 mA cm⁻² and an energy density of 4.7 µWh cm⁻², maintained even at a high-power density of 80 µW cm⁻². Remarkably, the device retains 96.7% of its capacitance after 8000 bending and charge–discharge cycles, demonstrating excellent electrochemical durability. This study highlights the effectiveness of MWCNT incorporation in enhancing MXene-based electrode architectures and establishes a co-engineering strategy that integrates material design with device architecture, offering a promising pathway to translate optimized MXene composites into flexible and wearable energy storage systems for next-generation IoT applications.