The modern lithium-ion battery (LIB) configuration was enabled by the “magic chemistry” between ethylene carbonate (EC) and graphitic carbon anode. Despite the constant changes of cathode chemistries with improved energy densities, EC-graphite combination remained static during the last three decades. Electrolytes in modern Li-ion batteries (LIBs) rely on additives of various structures to generate key interphasial chemistries needed for desired performances, although how these additives operate in battery environments remains little understood. In this work, different film-forming additives, including the state-of-art SEI and CEI additives were studied to investigate their influence on electrolyte-electrode interphase. Furthermore, the impact of electrolyte on the structural changes upon long-term cycling is further clarified. The correlation established among the additive structure, interphasial chemistries and cell performance offer the guide in designing the electrolytes with atomistic precision for future battery chemistries.