Synergistic Integration of MXenes with Conducting Polymers to Enhance the Specific Capacitance of Asymmetric Supercapacitors

MXenes (Ti ₃C ₂ T_x), a novel class of two-dimensional (2D) materials, have emerged as promising candidates for supercapacitor electrodes because of their remarkable solution processability, inherent metallic conductivity, and excellent energy storage abilities. Nevertheless, the self-stacking and interlayer interactions of MXenes hinder their electrochemical performance. To address these intrinsic defects and improve electrical conductivity, binary and ternary composites of MXenes with conducting polymers are utilized to develop flexible asymmetric supercapacitors. In these supercapacitors, MXene, MXene- PANI, and MXene- PANI- PEDOT: PSS serve as cathode materials, while pBOA functions as the anode. The supercapacitor using MXene- PANI- PEDOT: PSS showed an impressive specific capacitance of 279 F /g, exceeding the specific capacitances of the MXene- PANI and MXene-based supercapacitors, which were 153 and 68 F/g, respectively, at 5 mV/s. The energy densities achieved by the MXene-PANI-PEDOT: PSS, MXene-PANI, and pristine MXene-based supercapacitors were 13, 7.3, and 3 Wh/kg, respectively. All supercapacitors retained excellent capacitance after 10,000 continuous GCD cycles at 1 A /g. The supercapacitors incorporating MXene- PANI- PEDOT: PSS, MXene- PANI, and MXene exhibited equivalent series resistances (Rs) of 27.19, and 37.43, and 75.71 Ω, respectively, alongside charge transfer resistances (Rct) of 28.03, 38.72, and 77. 57 Ω, respectively. The lowest equivalent series resistance for the pBOA//MXene- PANI- PEDOT- PSS device is attributed to the superior conductivity of PEDOT: PSS, as evidenced by IV results, which reveal that MXene- PANI- PEDOT: PSS has a sheet resistance of merely 0. 3 KΩ/sq. Moreover, various loads can function using asymmetric devices configured in a series arrangement. This exploration of asymmetric supercapacitors further boosts the real-time applicability of MXene-based flexible energy storage devices.