POWER STORAGE DEVICE

To provide a power storage device capable of securing an output while reducing diffusion of lithium ions that do not involved in charging and discharging.SOLUTION: A power storage device includes, in order, a positive electrode layer, an electrolyte layer, and a negative electrode layer. The positive electrode layer, the electrolyte layer, and the negative electrode layer each include an electrolyte having lithium ion conductivity. The electrolyte of the positive electrode layer includes a solid electrolyte and the positive electrode layer further includes an active material in contact with the electrolyte. The atomic number concentration of Li in the electrolyte of the positive electrode layer is higher than the atomic number concentration of Li in the electrolyte of the electrolyte layer and higher than the atomic number concentration of Li in the electrolyte of the negative electrode layer.SELECTED DRAWING: Figure 2 【課題】充放電に関わらないリチウムイオンの拡散を低減しつつ出力を確保できる蓄電デバイスを提供する。【解決手段】蓄電デバイスは、順に、正極層、電解質層、負極層を含み、正極層、電解質層および負極層は、それぞれリチウムイオン伝導性を有する電解質を含む。正極層の電解質は固体電解質を含み、正極層は、さらに電解質に接する活物質を含む。正極層の電解質におけるＬｉの原子数濃度は、電解質層の電解質におけるＬｉの原子数濃度よりも高く、かつ、負極層の電解質におけるＬｉの原子数濃度よりも高い。【選択図】図２