Abstract: A cathode active material for a lithium rechargeable battery is provided. The cathode active material is used for a lithium rechargeable battery containing a cathode, an anode, and an electrolytic solution. The cathode active material is composed of 0.5% by weight or less carbonate ion (CO32?) plus bicarbonate ion (HCO3?) and 0.1% by weight or less hydroxyl ion (OH?). The swelling of lithium battery containing the cathode active material is substantially suppressed when is placed at 60° C. or more.

Abstract: The present invention relates to an electrolytic solution for a lithium battery and a lithium battery using the same. The organic electrolytic solution includes a lithium salt, a mixed organic solvent comprising a high dielectric constant solvent and a low boiling-point solvent, and an additive. The additive used in the electrolytic solution is a heterocyclic compound of Formula (1): where R1, R2 and R3 may each independently be a C1-C10 linear or branched alkyl group; R4 may be a C1-C10 linear or branched alkylene group; X may be a heterocyclic ring containing N and O whereby a tetraallkyl orthosilicate functional group may be linked to N. The lithium battery using the organic electrolytic solution of the present invention is highly reliable and maintains a constant thickness during a charge/discharge cycle.

Abstract: An organic electrolytic solution comprising a nonaqueous solvent and a lithium salt, wherein the organic electrolytic solution comprises a compound of Formula 1 and at least one selected from compounds of Formulas 2 through 5: 1

Abstract: An organic electrolytic solution includes a lithium salt and an organic solvent containing a phosphonate compound, and a lithium battery utilizes the organic electrolytic solution. When using the organic electrolyte containing the phosphonate compound to manufacture a lithium secondary battery, the lithium secondary battery has improved stability to reduction-induced decomposition, reduced first cycle irreversible capacity, and improved charging/discharging efficiency and lifespan. In addition, the lithium secondary battery does not swell beyond a predetermined thickness range after formation and standard charging at room temperature and has improved reliability. Even when the lithium secondary battery swells seriously at a high temperature, its capacity is high enough for practical applications. The capacity of the lithium secondary battery may substantially be recovered after being left at a high temperature.