Binder-Free MoS₂@TiO₂ Heterojunction by In-Situ Magnetron Sputtering: Interfacial Defect Engineering for...

To address the conductivity and volume-expansion bottlenecks of MoS₂ anodes, we report a scalable, binder-free MoS₂@TiO₂ heterojunction fabricated by an in situ two-stage magnetron sputtering strategy. Vertically aligned MoS₂ nanosheets are conformally capped with an amorphous, oxygen-vacancy-rich TiO₂ skin. The electrode retains 507 mAh g^-1 with ∼100% Coulombic efficiency after 500 cycles at 2 A g^-1 and delivers 1135 mAh g^-1 even at 20 A g^-1. XPS/UPS quantifies high-density oxygen vacancies (O_vs) in TiO₂, while DFT reveals these vacancies lower Li⁺ adsorption energy to -4.003 eV and drive electron accumulation into MoS₂. EIS verifies a charge-transfer resistance of only 22.4 Ω, and CV confirms pseudocapacitive-dominated kinetics. DOS/band-alignment analysis substantiates that O_vs generate a built-in electric field pointing from TiO₂ to MoS₂, which promotes interfacial charge redistribution and accelerates Li⁺ adsorption and diffusion. These atomistic insights into the interfacial electronic structure modulation highlight an industrially compatible interface-engineering route for fast-charging lithium-ion anodes.