Our new paper in Journal of Power Sources (Q1) "Effects of MoS2 Exfoliation State on Structural and Interfacial Stability of Si–MoS2 Composite Anodes for Li-ion Batteries"

Silicon (Si) anodes suffer from severe volume expansion and unstable solid electrolyte interphase (SEI), limiting their practical application in lithium-ion batteries. Here, we present Si–MoS₂ composite anodes that are constructed via liquid-phase exfoliation of MoS₂ followed by spray-drying integration with Si. Bath ultrasonication produces thin-flake MoS₂ with reduced stacking coherence and expanded interlayer spacing (~0.625 nm), enabling a more uniform composite structure and improved dispersion of Si particles. Composition screening identifies Si–MoS₂ (thin, 50:50) as the optimal configuration, delivering 1083 mAh g⁻¹ after 300 cycles, significantly outperforming the thick-flake counterpart fabricated by probe ultrasonication (688 mAh g⁻¹). Electrochemical impedance spectroscopy (EIS) reveals lower interfacial resistance, while X-ray photoelectron spectroscopy (XPS) indicates reduced surface coverage by SEI species in the thin-flake composite. In addition, the thin-flake electrode exhibits more stable voltage profiles with reduced polarization during cycling. Cross-sectional analysis shows minimal thickness expansion (~8%) compared to severe swelling (~115%) in the thick-flake electrode, highlighting substantial differences in mechanical stability. These results indicate that the electrochemical contribution of MoS₂ is limited under the applied voltage window, and that it primarily functions as a structural and interfacial regulator. This work demonstrates that controlling the exfoliation state of MoS₂ provides an effective strategy to regulate interfacial stability and mechanical integrity, offering practical guidance for the design of durable high-capacity Si-based anodes.