| abstract |
Provided is a secondary battery comprising: a positive electrode having a positive electrode active material layer which contains a lithium-cobalt composite oxide having a layered rock salt-type crystal structure; a negative electrode having a negative electrode active material layer containing graphite; and an electrolyte. When the secondary battery is charged and discharged with the upper limit value of a closed circuit voltage of 4.42 V or higher, the relationship between unit capacity (mAh/g) and area ratio (%) satisfies the conditional expression represented by 168 mAh/g ≤ unit capacity (mAh/g) ≤ (-0.28×area ratio (%)+178) mAh/g. |