| 主权项 |
1. A rechargeable lithium battery comprising:
a positive electrode comprising a current collector, a positive active material layer on the current collector and comprising a lithium manganese-based positive active material, and a protective layer on the positive active material layer and comprising a decomposition product of a phosphite-based compound; the phosphite-based compound having a Highest Occupied Molecular Orbital (“HOMO”) value of −10 eV to −7 eV and a Lowest Occupied Molecular Orbital (“LUMO”) value of 1 to 1.3 eV; a negative electrode; and an electrolyte comprising a lithium salt, a non-aqueous solvent and an additive, wherein the additive is an ethylene carbonate-based compound represented by the following Chemical Formula 3, an isoxazole compound represented by the following Chemical Formula 4, or a combination thereof, wherein X and Y are identical or different, and are selected from the group consisting of hydrogen, halogens, cyano (CN), nitro (NO2) and a substituted alkyl, provided that at least one of X or Y is a halogen or a substituted alkyl, wherein an amount of the phosphite-based compound is about 0.1 wt % to 10 wt % based on a total weight of the lithium salt and the non-aqueous solvent, and an amount of the additive is 0.1 parts to 5 parts by weight based on a total 100 parts by weight of the lithium salt and the non-aqueous solvent, and wherein the protective layer comprises the decomposition product of the phosphite-based compound represented by Chemical Formula 1, wherein A, D, and E are identical or different, and are selected from the group consisting of Si, Ge and Sn; and R1 to R9 are identical or different, and are selected from the group consisting of hydrogen, a substituted alkyl and an unsubstituted alkyl, and wherein the weight fraction of the protective layer is about 3 to 35 parts by weight based on 100 parts by weight of the positive active material layer. |
