Nonaqueous secondary battery

Claim 2

The nonaqueous secondary battery as defined in claim 1, wherein said mixed solvent comprises ethylene carbonate and at least one selected from the group consisting of chain carbonic acid esters, cyclic carbonic acid esters having carbon atoms of not less than 5, chain ethers and cyclic ethers.

Claim 3

The nonaqueous secondary battery as defined in claim 1, wherein said mixed solvent comprises ethylene carbonate and chain carbonic acid esters, or comprises ethylene carbonate, chain carbonic acid esters and at least one selected from the group consisting of cyclic carbonic acid esters having carbon atoms of not less than 5, cyclic esters, chain ethers and cyclic ethers.

Claim 4

The nonaqueous secondary battery as defined in claim 1, wherein said mixed solvent comprises ethylene carbonate, chain carbonic acid esters and at least one selected from the group consisting of cyclic carbonic acid esters having carbon atoms of not less than 5, cyclic esters, chain ethers and cyclic ethers.

Claim 5

The nonaqueous secondary battery as defined in claim 1, wherein said mixed solvent comprises ethylene carbonate and at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, butyl carbonate, γ-butyrolactone, dimethoxyethane and tetrahydrofuran.

Claim 6

The nonaqueous secondary battery as defined in claim 1, wherein said mixed solvent contains ethylene carbonate in the amount of 10 to 35 % in volume.

Claim 7

The nonaqueous secondary battery as defined in claim 1, wherein said lithium salt is at least one selected from the group consisting of LiBF₄, LiPF₆ and LiCF₃SO₃.

Claim 8

The nonaqueous secondary battery as defined in claim 1, wherein said anode active material is a transition metal oxide of which an inherent crystal structure has been changed by insertion of lithium ions, and is in the condition that said changed crystal structure is essentially not changed during repeated charging and discharging.

Claim 9

The nonaqueous secondary battery as defined in claim 1, wherein said cathode active material comprises a lithium-containing transition metal oxide represented by Li y MO z in which M is at least one transition metal selected from the group consisting of Co, Mn, Ni, V and Fe, y is in the range of 0.3 to 1.2, and z is in the range of 1.4 to 3.

Claim 10

A nonaqueous secondary battery which comprises a cathode active material, an anode active material and an electrolytic solution; wherein said anode active material comprises a transition metal oxide of which an inherent crystal structure has been changed by insertion of lithium ions and is in the condition that said changed crystal structure is essentially not changed during repeated charging and discharging, and said electrolytic solution comprises a fluorine-containing lithium salt in a mixed solvent which comprises ethylene carbonate and at least one selected from the group consisting of chain carbonic acid esters, cyclic carbonic acid esters having carbon atoms of not less than 5, cyclic esters, chain ethers and cyclic ethers.

Claim 11

The nonaqueous secondary battery as defined in claim 10, wherein said mixed solvent contains ethylene carbonate in the amount of not more than 48 % in volume.

Claim 12

The nonaqueous secondary battery as defined in claim 10, wherein said mixed solvent contains ethylene carbonate in the amount of not more than 5 to 45 % in volume.

Claim 13

The nonaqueous secondary battery as defined in claim 10, wherein said mixed solvent comprises ethylene carbonate and at least one selected from the group consisting of chain carbonic acid esters, cyclic carbonic acid esters having carbon atoms of not less than 5, chain ethers and cyclic ethers.

Claim 14

The nonaqueous secondary battery as defined in claim 10, wherein said mixed solvent comprises ethylene carbonate and chain carbonic acid esters, or comprises ethylene carbonate, chain carbonic acid esters and at least one selected from the group consisting of cyclic carbonic acid esters having carbon atoms of not less than 5, cyclic esters, chain ethers and cyclic ethers.

Claim 15

The nonaqueous secondary battery as defined in claim 10, wherein said lithium salt is at least one selected from the group consisting of LiBF₄, LiPF₆ and LiCF₃SO₃.

Claim 16

The nonaqueous secondary battery as defined in claim 10, wherein said anode active material comprises a lithium-containing transition metal oxide represented by Li x MO j wherein M is at least one transition metal selected from the group consisting of Ti, V, Mn, Co, Fe, Ni, Cr, Nb and Mo, x is in the range of 0.17 to 11.25, and j is in the range of 1.6 to 4.1.

Claim 17

The nonaqueous secondary battery as defined in claim 10, wherein said cathode active material comprises a lithium-containing transition metal oxide represented by Li y MO z in which M is at least one transition metal selected from the group consisting of Co, Mn, Ni, V and Fe, y is in the range of 0.3 to 1.2, and z is in the range of 1.4 to 3.