| 摘要 |
It is difficult to obtain discharge capacity as high as the theoretical capacity in the case where silicon is used as a negative electrode active material. Therefore, objects are to provide a negative electrode active material capable of increasing discharge capacity and to provide a high-performance power storage device including the negative electrode active material. As the negative electrode active material with which the objects are achieved, a silicon crystal body including a plurality of crystalline regions is provided. The silicon crystal body has one extension direction. The plurality of crystalline regions have respective crystal orientations that are substantially the same (also referred to as a preferred orientation). The extension direction and the preferred direction are substantially the same. |
