| 摘要 |
<p>A lithium-ion secondary battery 100 includes a positive electrode current collector 221 and a porous positive electrode active material layer 223 retained by the positive electrode current collector 221. The positive electrode active material layer 223 contains, for example, positive electrode active material particles 610, an electrically conductive material 620, and a binder 630. In this lithium-ion secondary battery 100, the positive electrode active material particles 610 have a shell portion 612 constituted by a lithium transition metal oxide, a hollow portion 614 formed inside the shell portion 612, and a through hole 616 penetrating the shell portion 612. In the lithium-ion secondary battery 100, in the positive electrode active material layer 223 on average, the hollow portion 614 accounts for 23% or higher of an apparent sectional area of the positive electrode active material particles 610. In addition, a thickness of the shell portion 612 in the positive electrode active material layer 223 on average is 2.2 µm or less.</p> |
