This chapter discusses in detail the diverse battery chemistries including the lithium-ion, lithium-metal and other advanced battery concepts. Emphasis is placed on the discovery process of lithium-ion batteries, especially the ethylene carbonate (EC)-based electrolyte and its interphasial chemistry on a graphitic anode, from which we learn how an electrolyte has to synchronize with all components in the battery while accommodating their extreme operating potentials. A brief summary of state-of-the-art electrolytes is also presented.