In this study, in-situ carbon coating technology was used to embed the sulfide-loaded MXene in the carbon nanofibers through electrospinning to improve the sulfide conductivity and ion transfer rate. Polyacrylonitrile (PAN) with a high carbon conversion rate was used as carbon nanofiber, while polyvinylpyrrolidone (PVP) with a low carbon conversion rate was used as a pore-forming sacrificial agent . PAN–PVP-based porous carbon nanofibers (PCNF) with good meso/macropore structure were prepared via a thermally induced phase separation process. FeCo 2 S 4 nanoparticles and ultra-thin Ti 3 C 2 T x MXene were uniformly fixed in PCNF in situ, and a flexible hybrid film was prepared as the electrode material of supercapacitors (FeCo 2 S 4 /MXene/PCNF). The FeCo 2 S 4 /MXene/PCNF hybrid membrane inherits a three-dimensional pore structure and hierarchical PCNF nanostructure . It can provide continuous channels for the rapid electrolyte diffusion, thereby obtaining electrochemically active FeCo 2 S 4 nanoparticles. Moreover, carbon nanofibers can act as a conductive core for providing effective electron transport for the rapid Faraday redox reaction of the FeCo 2 S 4 sheath or as a buffer matrix for reducing local volume expansion/contraction during long-term cycling. Therefore, the optimized FeCo 2 S 4 /MXene/PCNF hybrid membrane has excellent cyclic stability, which fundamentally solves the problems of poor sulfide conductivity and cyclic stability.