Binder composition for non-aqueous secondary battery positive electrode, composition for non-aqueous secondary battery positive electrode, positive electrode for non-aqueous secondary battery, and non-aqueous secondary battery, and methods for producing composition for non-aqueous secondary battery positive electrode, positive electrode for non-aqueous secondary battery, and non-aqueous secondary battery
Provided is a binder composition for a non-aqueous secondary battery positive electrode that can form a positive electrode with which it is possible to obtain a non-aqueous secondary battery having excellent life characteristics even when aging treatment is carried out under low-temperature and low-depth of charge conditions. The binder composition contains a first binder, iron, and at least one of ruthenium and rhodium. The total iron, ruthenium, and rhodium content is no greater than 5×10 −3 parts by mass per 100 parts by mass of the first binder.
1. A binder composition for a non-aqueous secondary battery positive electrode, comprising:
a first binder; iron; and at least one of ruthenium and rhodium, wherein
total iron, ruthenium, and rhodium content is no greater than 5×10 −3 parts by mass per 100 parts by mass of the first binder, and
iron content is at least 4×10 −5 parts by mass and no greater than 4×10 −3 parts by mass per 100 parts by mass of the first binder.
2. The binder composition for a non-aqueous secondary battery positive electrode of claim 1 , wherein
total ruthenium and rhodium content is at least 4×10 −5 parts by mass and no greater than 4×10 −3 parts by mass per 100 parts by mass of the first binder.
3. The binder composition for a non-aqueous secondary battery positive electrode of claim 1 , wherein
the first binder includes a polymer including an alkylene structural unit and a nitrile group-containing monomer unit.
4. The binder composition for a non-aqueous secondary battery positive electrode of claim 3 , wherein
the polymer has a degree of swelling in electrolysis solution of at least 200 mass % and no greater than 700 mass %.
5. The binder composition for a non-aqueous secondary battery positive electrode of claim 3 , wherein
the polymer has an iodine value of at least 0.01 mg/100 mg and no greater than 65 mg/100 mg.
6. The binder composition for a non-aqueous secondary battery positive electrode of claim 3 , wherein
the polymer includes the alkylene structural unit in a proportion of at least 20 mass % and no greater than 90 mass % and includes the nitrile group-containing monomer unit in a proportion of at least 10 mass % and no greater than 60 mass %.
7. A composition for a non-aqueous secondary battery positive electrode, comprising:
a positive electrode active material; a conductive material; and the binder composition for a non-aqueous secondary battery positive electrode of claim 1 .
8. A composition for a non-aqueous secondary battery positive electrode, comprising:
the binder composition for a non-aqueous secondary battery positive electrode of claim 1 ; and a second binder, wherein
the second binder includes a fluorine-containing polymer.
9. The composition for a non-aqueous secondary battery positive electrode of claim 8 , wherein
the fluorine-containing polymer has a melt viscosity of at least 1.0 kPa·s.
10. The composition for a non-aqueous secondary battery positive electrode of claim 8 , wherein
the second binder is contained in a proportion of at least 50 mass % and no greater than 99.9 mass % relative to total content of the first binder and the second binder.
11. The composition for a non-aqueous secondary battery positive electrode of claim 8 , wherein
the fluorine-containing polymer includes a vinylidene fluoride unit.
12. The composition for a non-aqueous secondary battery positive electrode of claim 8 , further comprising
a conductive material.
13. The composition for a non-aqueous secondary battery positive electrode of claim 8 , further comprising
a positive electrode active material.
14. The composition for a non-aqueous secondary battery positive electrode of claim 8 , further comprising
a positive electrode active material and a conductive material.
15. A method for producing the composition for a non-aqueous secondary battery positive electrode of claim 8 , comprising
mixing the binder composition for a non-aqueous secondary battery positive electrode and the second binder.
16. A positive electrode for a non-aqueous secondary battery, comprising
a positive electrode mixed material layer formed using the composition for a non-aqueous secondary battery positive electrode of claim 7 .
17. A method for producing a positive electrode for a non-aqueous secondary battery, comprising:
applying the composition for a non-aqueous secondary battery positive electrode of claim 7 onto a current collector; and
drying the composition for a non-aqueous secondary battery positive electrode that has been applied to form a positive electrode mixed material layer at a temperature of at least 120° C.
18. A non-aqueous secondary battery comprising:
the positive electrode for a non-aqueous secondary battery of claim 16 ; a negative electrode; an electrolysis solution; and a separator.
19. A method for producing a non-aqueous secondary battery, comprising:
assembling a non-aqueous secondary battery including the positive electrode for a non-aqueous secondary battery of claim 16 , a negative electrode, an electrolysis solution, and a separator; and
subjecting the non-aqueous secondary battery that has been assembled to aging treatment, wherein
the aging treatment is carried out under conditions of a depth of charge of no greater than 13% and a temperature of no higher than 55° C.