MXene-modified and electrochemically enhanced polyaniline hydrogels for flexible asymmetric supercapacitors

Efficiently preparing polyaniline (PANI) supercapacitor electrode materials with exceptional electrochemical performance is vital for their utilization in energy storage devices, notwithstanding the difficulties involved. We developed a direct hydrothermal assembly approach to construct MXene-modified PANI hydrogel (M-PANI) using PANI dispersion modified by highly conductive MXene. The findings suggest that the breakdown of MXene nanosheets and the conversion into TiO₂ from part of MXene by hydrothermal treatment may notably boost the electrochemical performances of M-PANI hydrogels. The prepared M-PANI hydrogel electrodes exhibit high specific capacitance (483.1 F g⁻¹ at 1 A g⁻¹), superior rate capability (79.8 % from 1 to 20 A g⁻¹), and valuable cycling durability (80 % of initial capacitance after 6000 cycles). The flexible asymmetric supercapacitors (MXene//M-PANI) were further assembled using MXene as anode and M-PANI as cathode materials, which achieve high specific capacitance (128.2 F g⁻¹ at 1 A g⁻¹), satisfying energy density (23.6 W h kg⁻¹ at 575 W kg⁻¹), and favorable cycling durability (89.4 % retention of the initial capacitance after 9000 cycles). The generated M-PANI hydrogels with remarkable electrochemical performances as supercapacitor electrodes suggest their enormous potential in the field of cutting-edge energy storage technology.