Technological breakthroughs in the energy transition hinge on finding earth‐abundant materials that can convert between electricity and chemical bond energy at a faster rate for a prolonged lifetime. This mission can only be accomplished with a fundamental understanding of the solid/liquid interfaces, also known as the electrical double layer (EDL), at which most important conversion processes occur. However, we are struggling with precise measurement and high‐fidelity modeling of basic thermodynamic quantities, notably the capacitance, entropy and surface stress, of EDL. It is thus imperative to bring together scientists with a wide range of expertise in experiments (single‐crystal preparation and characterization, electrochemical impedance, microcalorimetry, etc) and theory (continuum theory, molecular dynamics simulation, density functional theory, machine learning potentials) to discuss these specific topics in a level of depth greater than that in regular scientific meetings and conferences.