The workshop focuses on the fundamental role of solid-liquid interfaces in electrochemical systems for energy and sustainability. Understanding these complex environments requires integrating theoretical modeling with advanced experimental techniques. The program will explore how in situ and operando characterization methods (Synchrotron-based X-ray techniques, liquid-phase transmission electron microscopy, Raman spectroscopy) combined with atomistic simulations (Density Functional Theory, ab initio molecular dynamics, machine-learning-assisted models) can reveal the morphological, structural, electronic, and chemical dynamics governing electrochemical reactivity. A central theme will be linking interfacial behavior across scales: from electronic and molecular processes such as charge transfer, solvation, and reaction pathways, to mesoscopic mass transport and surface chemistry, up to device-level performance where these coupled phenomena determine efficiency and stability. Case studies on materials for electrocatalysis, energy storage, and energy conversion will illustrate how synergistic theory-experiment strategies accelerate the design of sustainable, low-carbon technologies. Interactive discussions will encourage participants to share methods, challenges, and opportunities, fostering collaborations to address key issues in the energy transition.