| 摘要 |
A lithium ion secondary battery which comprises a positive electrode, a negative electrode and an electrolyte. The active material of the positive electrode is represented by general formula LiaMnxNiyCozO2 (wherein a, x, y and z are parameters satisfying 1.1 ≤ a ≤ 1.2, 0.45 ≤ x ≤ 0.55, 0.15 ≤ y ≤ 0.35 and 0 ≤ z ≤ 0.15). The active material of the negative electrode is composed of graphite and an Si alloy, and the mass ratio of the graphite to the Si alloy, namely (mass of graphite)/(mass of Si alloy) is from 0.67 to 9 (inclusive). |
