Synergy of MXene with Se Infiltrated Porous N‐Doped Carbon Nanofibers as Janus Electrodes for High‐Performance Sodium/Lithium–Selenium Batteries

Abstract Metal–selenium (M–Se) batteries are considered promising candidates for next‐generation battery technologies owing to their high energy density and high‐rate capability. However, Se cathode suffers from poor cycling performance and low Coulombic efficiency, owing to the shuttle effect of polyselenides. Herein, it is reported the incorporation of Ti 3 C 2 T x MXene onto Se infiltrated porous N‐doped carbon nanofibers (PNCNFs) to construct free‐standing Janus PNCNFs/Se@MXene cathodes for high‐performance Na–Se and Li–Se batteries. The increase of pyrrolic‐N content and the porous structure of the PNCNFs is conducive to enhancing the adsorption of Na 2 Se and alleviating the shuttle effect. Meanwhile, density functional theory (DFT) calculations have proven that 2D Ti 3 C 2 T x MXene with polar interfaces enables the effective chemical immobilization and physical blocking of polyselenides to suppress the shuttle effect. The unique architecture with Ti 3 C 2 T x MXene built on top of interlinked nanofiber ensures the continuous electron transfer for redox reaction. As a result, the novel Janus PNCNFs/Se@MXene electrodes deliver robust rate capabilities and superior long‐term cycling stability in both Na–Se and Li–Se batteries. The incorporation of 2D MXene to construct Janus electrodes provides a competitive advantage for selenium‐based cathode materials and highlights a new strategy for developing high‐performance batteries.