Interface engineering of Metal/MoS₂ for improving supercapacitor behaviour: How metal contacts create the Defects, Orientation and band alignment

Molybdenum disulfide (MoS₂), a layered transition metal dichalcogenide, has emerged as a promising electrode material for supercapacitors due to its two-dimensional structure, large surface-to-volume ratio with excellent electrochemical properties. In this study,  MoS₂ thin films were deposited on various metallic substrates (having different interaction with film) using DC magnetron sputtering to investigate the influence of substrate film interactions on the structural, electronic, and electrochemical characteristics. The effect of metal contact on defect formation, crystal orientation, and band alignment at the Metal/MoS₂ interface was systematically analysed. The interfacial properties, including lattice mismatch and band alignment, were correlated with the electrochemical behaviour obtained from cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Ultraviolet photoelectron spectroscopy (UPS) was employed to determine the band alignment and Fermi level shifts induced by different metal substrates. The results reveal that the metal semiconductor interface significantly influencing the charge transfer behaviour, chemical reactivity, and overall capacitive performance of MoS₂. These findings highlight the role of interface in the electrochemical performance supercapacitors.