To provide a power storage device with improved cycle characteristics. In the power storage device, a conductive catalyst layer is provided in contact with a surface of an active material layer formed of silicon or the like and a carbon layer is provided over the conductive catalyst layer. The carbon layer is formed by a CVD method using an effect of the catalyst layer. The carbon layer formed by a CVD method is crystalline and helps prevent an impurity such as an SEI from being attached to a surface of an electrode of the power storage device, leading to improvements in cycle characteristics of the power storage device.