Thermotropic liquid-crystalline (LC) electrolytes for lithium-ion batteries are developed for the first time. A rod-like LC molecule having a cyclic carbonate moiety is used to form self-assembled two-dimensional ion-conductive pathways with lithium salts. Electrochemical and thermal stability, and efficient ionic conduction is achieved for the liquid crystal. The mixture of the carbonate derivative and lithium bis(trifluoromethylsulfonyl)imide is successfully applied as an electrolyte in lithium-ion batteries. Reversible charge-discharge for both positive and negative electrodes is observed for the lithium-ion batteries composed of the LC electrolyte.