Compressible and Lightweight MXene/Carbon Nanofiber Aerogel with “Layer-Strut” Bracing Microscopic Architecture for Efficient Energy Storage

Two-dimensional MXene has recently captured widespread research attention in energy storage and conversion fields due to its high conductivity, large specific surface area, and remarkable electro-activity. However, its performance is still hindered by severe self-restacking of MXene flakes. Herein, conductive Ti 3 C 2 T x /carbon nanofiber (CNF) composite aerogel with typical “layer-strut” bracing 3D microscopic architecture has been fabricated via synergistic assembly and freeze-drying process. In virtu of the strong interfacial interaction between polymeric precursor nanofibers and MXene mono-layers, gelation capability and 3D formability of Ti 3 C 2 T x is greatly reinforced, as resulted Ti 3 C 2 T x /CNF aerogels possess a highly ordered microporous structure with interlayered CNF penetrating between large size MXene lamellae. This special configuration guarantees the stability and pliability of the composite aerogels. Furthermore, the 3D form interconnected conductive network and the parallell alignment of the pores allow  free electrical carriers motion and ion migration. As a result, the prepared Ti 3 C 2 T x /CNF aerogel-based electrode exhibits an exceptional gravimetric specific capacitance of 268 F g −1 at a current density of 0.5 A g −1 and an excellent cycling stability of 8000 cylcles, and the assembled symmetric supercapacitor, delivers a high energy density of 3.425 W h kg −1 at 6000 W kg −1 . This work offers a new route for the rational construction of 3D MXene assembly for advanced energy storage materials. Graphical abstract