A Si‐MoSe ₂ Heterostructured Anode with Enhanced Thermal Transport and Electrochemical Performance for Liquid and All‐Solid‐State Lithium‐Ion Batteries

ABSTRACT Silicon anodes offer high theoretical capacity for lithium‐ion batteries but suffer from volume‐change‐induced instability and degradation. Conventional van der Waals coatings yield unstable interfaces and poor ion/electron transport, while thermal transport remains underexplored. Here, we propose heterointerface‐engineered Si@MoSe 2 @C anodes with chemically bonded interfaces, where lattice‐matched MoSe 2 covalently bridges porous Si and carbon coating, forming robust Si─Se─Mo linkages that stabilize the structure and optimize transport pathways. The Si@MoSe 2 @C anode delivers 1054 mAh g −1 after 100 cycles at 0.2 A g −1 —exceeding most Si anodes—and 99.5% Coulombic efficiency over 400 cycles at 1.0 A g −1 , with high cycling efficiency demonstrated in both liquid and all‐solid‐state lithium‐ion batteries (ASSLIBs). In situ X‐ray diffraction, Raman spectroscopy, and electron microscopy/spectroscopy, together with first‐principles calculations, confirm that this MoSe 2 ‐mediated covalent bridging enables reversible reactions with favorable kinetics and structural integrity by strengthening and delocalizing Se─Si bonding and reducing Li + migration barriers by 24%. Critically, we present the first measurements of the effective thermal conductivity of a silicon‐anode composite, showing that Si@MoSe 2 @C exhibits a 27% higher value than Si, addressing long‐overlooked cell‐level thermal‐management requirements and improving elevated‐temperature cell performance. This heterointerface design provides a synergistic strategy for engineering high‐performance Si anodes across batteries with enhanced safety.