Ni‐Bridged Biphasic Molybdenum Carbide Interfaces: A Synergistic Catalyst for High‐Performance Lithium–Selenium Batteries

Abstract Transition metal catalysts are key to developing high‐performance lithium‐selenium (Li‐Se) batteries. Herein, we report a rationally designed Ni‐bridged biphasic molybdenum carbide (Mo 2 C) with a multi‐interface structure that exposes abundant active sites and significantly enhances the electrochemically reversibility of Li–Se batteries under high current operation. The synergistic integration of catalytic and conductive functions facilitates the rapid deposition and conversion of Se/Li 2 Se x , effectively preventing electrode passivation caused by inactive accumulation during high‐rate and long‐term cycling. Furthermore, Ni serves dual roles as a structural bridge to link Mo 2 C lattice and an electronic modulator to optimize the d‐orbital configuration of Mo, thereby maximizing the catalytic efficiency of functionalized Mo 2 C. The synergistic effects of adsorption, desorption, and catalysis enable the rationally designed metal carbide/Se electrode to promote not only the rapid conversion of long‐chain Li 2 Se n species but also the solid–solid transformation of Li 2 Se 2 into Li 2 Se. As a result, the electrode achieves full‐process catalytic conversion in Li–Se batteries, delivering excellent cycling stability and high‐rate performance. Even under high Se loading (5.6 mg cm −2 ), the electrode delivers an initial capacity of 400 mAh g −1 at 0.1 C. These results highlight the effectiveness of the synergistic adsorption/desorption/catalysis mechanism in enabling a fast solid–solid conversion pathway for Li–Se batteries.