| 摘要 |
This negative electrode 3 for a lithium ion secondary battery contains, as the active material, (a) at least one material (below, referred to as the metal and/or metal oxide) selected from metals that can alloy with lithium and metal oxides that can occlude and release lithium ions and (b) a surface-coated carbon material that can occlude and release lithium ions, characterized by having a 0.78 or greater average value of circularity of the aforementioned metal and/or metal oxide particles, defined by expression (1) below: (1) Circularity = 4πS/L2 (here, S: surface area of projected particle image, L: circumferential length of projected particle image). A lithium ion secondary battery having said electrode has improved cycle characteristics. |
