Abstract: The research aimed at understanding of electrochemical interfaces will be presented, along with its impact on the design and synthesis of materials that are employed in electrochemical systems for energy conversion and storage. The key physical parameters that are responsible for functional properties of solid-aqueous, solid-organic and solid-solid electrochemical interfaces will be discussed. The research strategy is built on insights at the atomic/molecular level that define events controlled by electrode potential, which triggers electron and ion transfers across the electrochemical interfaces. Spatial arrangement, surface structure and nature of surface atoms will be correlated to the properties of double layer, including different reactive species, spectators and impurities. The research goes beyond material discoveries and extends towards modification of electrochemical interfaces in quest to improve their efficiency and durability.