Negative electrode for lithium ion secondary battery, and lithium ion secondary battery using the same
A negative electrode for a lithium ion secondary battery includes a current collector and an active material-containing layer disposed on the current collector. The active material-containing layer includes: a first negative electrode active material including a carbon material; a second negative electrode active material including a metal element or a metalloid element as a constituent element, the metal element or the metalloid element being capable of forming an alloy with lithium; and a binder. The first negative electrode active material contains a spherical graphite, and the binder contains an acrylic resin.
1. A negative electrode for a lithium ion secondary battery, the negative electrode comprising:
a current collector; and
an active material-containing layer disposed on the current collector, wherein
the active material-containing layer includes:
a first negative electrode active material including a carbon material;
a second negative electrode active material including a metal element or a metalloid element as a constituent element, the metal element or the metalloid element being capable of forming an alloy with lithium; and
a binder, wherein
the first negative electrode active material contains a spherical graphite
the second negative electrode active material contains amorphous SiO x , where 0<x<2,
the binder contains an acrylic resin,
a ratio (A+B)/C of a total of a weight A of the spherical graphite and a weight B of the amorphous SiO x to a weight C of the acrylic resin is 6 to 20, and
a ratio B/C of the weight B of the amorphous SiO x to the weight C of the acrylic resin is 1.4 to 3.
2. The negative electrode for a lithium ion secondary battery according to claim 1 , wherein
the second negative electrode active material containing the amorphous SiO x , is a mixture of silicon monoxide and silicon dioxide with elemental silicon.
3. The negative electrode for a lithium ion secondary battery according to claim 1 , wherein
a ratio A:B of a weight A of the first negative electrode active material to a weight B of the second negative electrode active material is 99:1 to 65:35.
4. A lithium ion secondary battery comprising:
the negative electrode for the lithium ion secondary battery according to claim 1 ;
a positive electrode; and
an electrolyte.
5. The negative electrode for a lithium ion secondary battery according to claim 1 , wherein
a ratio A:B of a weight A of the spherical graphite to a weight B of the amorphous SiO x is 99:1 to 65:35.
6. The negative electrode for a lithium ion secondary battery according to claim 1 , wherein
the ratio (A+B)/C is 7.1-14.3.
7. The negative electrode for a lithium ion secondary battery according to claim 1 , wherein
the ratio (A+B)/C is 7.1-14.3,
the ratio B/C is 1.4-2.9, and
a ratio A:B of a weight A of the first negative electrode active material to a weight B of the second negative electrode active material is a weight ratio of the first active material and the second active material is 80:20.