| CPC H01M 10/0525 (2013.01) [H01M 4/134 (2013.01); H01M 10/0587 (2013.01); H01M 2004/027 (2013.01)] | 7 Claims |

|
1. A lithium secondary battery comprising a positive electrode, a negative electrode, a lithium ion conductive nonaqueous electrolyte, and a separator disposed between the positive electrode and the negative electrode, wherein
on the negative electrode, a lithium metal deposits at the time of charging, and the lithium metal is dissolved in the nonaqueous electrolyte at the time of discharging,
the nonaqueous electrolyte contains a cation and an anion,
the cation comprises a lithium ion and at least one cation X selected from the group consisting of Na, K, Rb, Cs, Fr, Mg, Ca, Sr, Ba, and Al,
the anion comprises an oxalate borate complex anion Y, the oxalate borate complex anion Y containing fluorine, and
a concentration of the oxalate borate complex anion Y in the nonaqueous electrolyte is 0.5 mol/liter or less.
|