Engineering Cu ₄ Mo ₆ Se ₈ /Ti ₃ C ₂ Hetero‐Interfaces to Boost Magnesium Storage Kinetics of Bimetallic MOF‐Derived Selenide Cathode Material for Multilayer Magnesium Metal Pouch Cell

Conversion‐type selenide cathode materials have shown significant promise for magnesium metal batteries owing to their high theoretical capacity and “soft” lattice characteristics. However, conventional conversion‐type selenide cathodes still suffer from large volume changes, limited bulk‐phase utilization and polyselenide shuttling, leading to unsatisfactory magnesium storage capacity and cycling stability. Here, we construct a MOF‐derived Cu 4 Mo 6 Se 8 /Ti 3 C 2 (CMSe/Ti 3 C 2 ) cathode material with hetero‐interfaces. The hetero‐interface engineering effectively enhances the electronic conductivity and structural stability of CMSe while anchoring polyselenides during cycling. Meanwhile, the introduced 2D Ti 3 C 2 builds a continuous conductive network, synergistically improving charge transport, Mg 2+ diffusion, and bulk‐phase reaction participation. Benefiting from these effects, CMSe/Ti 3 C 2 delivers a high magnesium storage capacity of 215 mAh g −1 at 20 mA g −1 and retains 92% of its capacity over 1500 cycles at 500 mA g −1 . The reversible capacity increases from 54.5 mAh g −1 for CMSe to 122.1 mAh g −1 for CMSe/Ti 3 C 2 . Moreover, the assembled multilayer magnesium metal pouch cell achieves the highest capacity of 75 mAh. The magnesium storage mechanism of CMSe/Ti 3 C 2 based on conversion reactions is investigated through theoretical calculations and advanced characterization techniques. This work provides a new strategy for regulating the phase‐transition behavior and reversibility of conversion‐type selenide cathodes through hetero‐interface engineering.