NEGATIVE ELECTRODE ACTIVE MATERIAL LAYER AND METHOD FOR MANUFACTURING NEGATIVE ELECTRODE ACTIVE MATERIAL LAYER, ELECTRODE MIXTURE PASTE FOR POWER STORAGE DEVICE NEGATIVE ELECTRODE, POWER STORAGE DEVICE NEGATIVE ELECTRODE, AND POWER STORAGE DEVICE

A power storage device including a negative electrode active material layer which contains carbon particles, silicon-based particles and a polyimide-based binder, in which the negative electrode active material layer has a porosity of more than 40%. The power storage device has a high charge/discharge capacity and excellent cycle characteristics.