Negative electrode for lithium ion secondary battery, and lithium ion secondary battery
View Patent ↗This negative electrode is provided with a negative electrode current collector, and a negative electrode mixture layer formed on the negative electrode current collector, wherein: the negative electrode mixture layer comprises a first layer arranged on the negative electrode current collector, and a second layer arranged on the first layer; the second layer includes graphite particles A having a particle internal porosity of at most 10%: the first layer includes graphite particles B having a particle internal porosity of more than 10%; and the second layer has a water contact angle of at most 50°.
1. A negative electrode for a lithium ion secondary battery, the negative electrode comprising:
a negative electrode electricity collector; and
a negative electrode mixture layer formed over the negative electrode electricity collector, wherein
the negative electrode mixture layer includes a first layer disposed over the negative electrode electricity collector, and a second layer disposed over the first layer,
the second layer includes graphite particles A having a particle internal porosity of 10% or lower, and the first layer includes graphite particles B having a particle internal porosity of greater than 10%,
a water contact angle of the second layer is 50° or lower, and
a volume ratio of the graphite particles A in the second layer with respect to a total volume of the second layer is 29 volume % or greater.
2. The negative electrode for the lithium ion secondary battery according to claim 1 , wherein
the negative electrode mixture layer contains an alloying material which alloys with lithium and,
the alloying material is contained in a larger amount in the second layer than in the first layer.
3. The negative electrode for the lithium ion secondary battery according to claim 2 , wherein
the negative electrode mixture layer contains fibrous carbon, and
the fibrous carbon is contained in a larger amount in the second layer than in the first layer.
4. The negative electrode for the lithium ion secondary battery according to claim 1 , wherein
the negative electrode mixture layer contains styrene-butadiene rubber, and
the styrene-butadiene rubber is contained in a larger amount in the first layer than in the second layer.
5. The negative electrode for the lithium ion secondary battery according to claim 4 , wherein
90 mass % or greater and 100 mass % of the styrene-butadiene rubber contained in the negative electrode mixture layer is contained in a half region on the side near the negative electrode electricity collector.
6. The negative electrode for the lithium ion secondary battery according to claim 1 , wherein
a thickness of the second layer is ⅓ or greater of a thickness of the negative electrode mixture layer.
7. A lithium ion secondary battery comprising:
the negative electrode for the lithium ion secondary battery according to claim 1 .