Synergistic construction of 3D conductive aerogels for high-performance supercapacitors: polypyrrole @ aramid nanofibers core-shell with Ti3C2Tx intercalation

Two-dimensional materials, such as MXene (Ti 3 C 2 T x ), have recently garnered significant attention in the field of energy storage. However, their electrochemical performances are severely hindered by the tendency of their layered structures to restack. This study introduces an innovative strategy involving the in-situ polymerization of polypyrrole (PPy) microspheres on the surfaces of aramid nanofibers (ANFs) to form a stable PPy@ANFs core–shell structure. This structure serves as a conductive framework intercalated between Ti 3 C 2 T x nanosheets, producing an MXene/PPy@ANFs (MPA) aerogel with three-dimensional multidirectional conductive properties. The PPy@ANFs core–shell structure not only widens the ion transport pathways, but it also significantly inhibits the restacking of the Ti 3 C 2 T x layers. Additionally, the resulting interlayer spacing of the MXene effectively mitigates the swelling and pulverization of the PPy microspheres. This ternary synergistic effect endows the MPA 0.3 aerogel with a high specific capacitance of 404.9 F g −1 at 2 mV s −1 . Symmetric supercapacitors assembled with this material exhibit exceptional comprehensive performance, namely a specific capacitance of 169.84 F g −1 at 2 mV s −1 , a capacitance retention of 82 % at a high scan rate of 100 mV s −1 , and a capacity retention of 99.31 % after 10,000 cycles at a current density of 8 A g −1 . Furthermore, at a current density of 1 A g −1 , the device simultaneously achieves an energy density of 22.12 Wh kg −1 and a power density of 1280 W kg −1 . This work presents a novel three-dimensional structural design for MXene-based composites, providing valuable insights into their potential for advanced energy storage applications.