| 主权项 |
1. A lithium ion secondary battery comprising:
(i) a cathode comprising a cathode active material that can reversibly occlude and release lithium ions wherein the upper cut-off voltage for the cathode during charging against Li/Li+ is of at least 4.4 V; (ii) an anode comprising an anode active material comprising silicon; and (iii) a non-aqueous electrolyte comprising at least one lithium salt and at least one non-aqueous organic solvent selected from the group consisting of fluorinated carbonates and at least one optionally fluorinated boroxine of formula (IV): wherein R1, R2, and R3 are independently from each other are selected from the group consisting of (C1-C6)alkyl, (C1-C6)alkoxy, (C5-C7)aryl, and (C5-C7)aryloxy, and wherein alkyl, alkyloxy, aryl and aryloxy may be independently from each other substituted by one or more substituents selected from the group consisting of F, (C1-C6)alkyl, (C1-C6)alkoxy, (C5-C7)aryl, and (C5-C7)aryloxy and
each alkyl, alkoxy, aryl, or aryloxy may be substituted by one or more F. |
