A Si-MoSe₂ Heterostructured Anode with Enhanced Thermal Transport and Electrochemical Performance for Liquid and...

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@MoSe₂@C anodes with chemically bonded interfaces, where lattice-matched MoSe₂ covalently bridges porous Si and carbon coating, forming robust Si─Se─Mo linkages that stabilize the structure and optimize transport pathways. The Si@MoSe₂@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 MoSe₂-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@MoSe₂@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.