Abstract: An organic electrolyte containing an organic solvent mixture and a lithium (Li) salt, and a lithium secondary cell adopting the electrolyte. The organic electrolyte contains the organic solvent mixture comprising a solvent having a high dielectric constant, a solvent having a low viscosity and a compound expressed by the following chemical formula (1): ##STR1## wherein R.sub.1 and R.sub.2 are independently C.sub.1 to C.sub.3 linear or cyclic alkyl, and x is an integer from 1 to 4. The organic electrolyte for a lithium secondary cell is improved in ion conductivity, low-temperature storage characteristics, and a wide potential window region. Also, the lithium salt may be a mixture of inorganic lithium salts and organic lithium salts.