Abstract: A lithium secondary battery (10) disclosed includes a positive electrode (11), a negative electrode (12), a separator (13), and a nonaqueous electrolyte. The negative electrode (12) is a negative electrode in which a metal layer containing lithium is deposited during charging, and the metal layer dissolves during discharging. The negative electrode (12) includes a current collector containing copper. The negative electrode (12) contains at least one metal element M selected from the group consisting of metal elements having a melting point of 50° C. or lower as a simple substance and a metal element having the lowest melting point among metal elements that constitute an alloy having a melting point of 50° C. or lower. The negative electrode (12) contains the metal element M at an area density in a range of 0.001 mg/cm2 to 0.75 mg/cm2 in a region where the metal layer is deposited during charging.

Abstract: A lithium secondary battery including a positive electrode, a negative electrode, a lithium ion conductive nonaqueous electrolyte, and a separator disposed between the positive electrode and the negative electrode; on the negative electrode, a lithium metal deposits at the time of charging, the lithium metal dissolves in the nonaqueous electrolyte at the time of discharging; the nonaqueous electrolyte contains a cation and an anion; the cation includes 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; and the anion includes an oxalate complex anion Y.

Abstract: Disclosed is a lithium secondary battery (10) including a positive electrode (11), a negative electrode (12), and a non-aqueous electrolyte having lithium ion conductivity. In the negative electrode (12), lithium metal is deposited during charging, and the lithium metal is dissolved in the non-aqueous electrolyte during discharging. The non-aqueous electrolyte includes a solvent and a lithium salt. The solvent includes a non-fluorinated ether and a fluorinated cyclic monoether. The fluorinated cyclic monoether includes a cyclic structure having one ether bond. The lithium salt includes an anion of an oxalate complex.

Abstract: A lithium secondary battery includes positive and negative electrodes, and a nonaqueous electrolyte having lithium-ion conductivity. In the lithium secondary battery, lithium metal deposits on the negative electrode during charging, and the lithium metal dissolves from the negative electrode during discharging. The nonaqueous electrolyte contains a lithium salt, and a solvent. The solvent includes a first solvent: a chain ether containing no fluorine element, a second solvent: a chain fluorinated ether having a fluorination rate of 60% or more, and a third solvent: a fluorinated ether having a fluorination rate of more than 0% and less than 60%. When the number of moles of the first solvent contained in the nonaqueous electrolyte is M1, and the number of moles of the third solvent contained in the nonaqueous electrolyte is M3, a molar ratio M1/M3 is 0.25 or more and less than 3.

Abstract: A lithium secondary battery includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein the non-aqueous electrolyte includes a fluorinated vinylene ether compound A having a —CF?CH—O— bond, and a non-aqueous solvent.

Abstract: A lithium secondary battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte, wherein in the negative electrode, lithium metal deposits during charging and the lithium metal dissolves during discharging, the non-aqueous electrolyte includes a fluoroalcohol, an oxalate complex anion including fluorine, a lithium ion, and a non-aqueous solvent.

Abstract: A lithium secondary battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte. The positive electrode includes a lithium-transition metal composite oxide. The lithium-transition metal composite oxide contains at least Ni, and has a ratio of Ni to total metal elements other than Li of 90 mol% or more. In the negative electrode, lithium metal deposits during charge, and the lithium metal dissolves during discharge. The non-aqueous electrolyte includes a non-aqueous solvent, lithium ions, an oxalate complex anion having fluorine, and nitrate anions.

Abstract: A lithium secondary battery includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte. In the negative electrode, lithium metal deposits during charging and the lithium metal dissolves during discharging. The nonaqueous electrolyte includes a lithium ion, a cation of a metal M1 that forms an alloy with lithium, and a halide ion.

Abstract: A non-aqueous electrolyte secondary battery including a positive electrode, a separator, a negative electrode facing the positive electrode, with the separator interposed; and a liquid electrolyte. The positive electrode includes a composite oxide containing lithium as a first metal, and a second metal other than lithium. In the composite oxide, the second metal contains Ni, a content of Ni in the second metal is 90 at % or more, and a content of Co in the second metal is 10 at % or less. The liquid electrolyte contains at least one cation X selected from the group consisting of Na+, K+, Rb+, Cs+, Fe, Mg2+, Ca2+, Sr2+, Ba2+, and Al3+, and an oxalate complex anion Y.

Abstract: A lithium secondary battery including a positive electrode, a negative electrode, a lithium ion conductive nonaqueous electrolyte, and a separator disposed between the positive electrode and the negative electrode; on the negative electrode, a lithium metal deposits at the time of charging, the lithium metal dissolves in the nonaqueous electrolyte at the time of discharging; the nonaqueous electrolyte contains a cation and an anion; the cation includes 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; and the anion includes an oxalate complex anion Y.