Patent ID: 8574774

Claim:
A negative electrode comprising an aluminum alloy, wherein the alloy has a magnesium content of 0.0001% by weight or higher and 8% by weight or lower, the alloy comprises an intermetallic compound particle in a matrix of the alloy, in a surface of the alloy, a particle-number density of the intermetallic compound particle having a particle size of 0.1 μm 2 or larger and smaller than 100 μm 2 is 1000 particles/mm 2 or less, a particle-number density of the intermetallic compound particle having a particle size of 100 μm 2 or larger is 10 particles/mm 2 or less, an occupying area proportion of the intermetallic compound particle is 0.5% or smaller per unit area of the alloy surface, the alloy satisfies at least one condition selected from the group consisting of the following (A) and (B): (A) an iron content is 0.0001% to 0.005% by weight, and (B) a silicon content is 0.0001% by weight or higher and 0.02% by weight or lower, and a content of each element other than aluminum, magnesium, silicon and iron in the alloy is 0.005% by weight or lower.