摘要 |
To provide an all-solid lithium ion secondary battery having a high voltage, a small internal resistance, and a discharge capacity close to a theoretical capacity and being able to be produced at low cost, and therefore, even in the case of collective sintering, generation of an inactive material due to interface reaction at the interface between an electrode active material and a solid electrolyte is reduced. An all-solid lithium ion secondary battery including a positive electrode layer, a negative electrode layer, and a solid electrolyte layer disposed between the positive electrode layer and the negative electrode layer, wherein an electrode active material included in the positive electrode layer is a phosphate having an olivine structure; and a solid electrolyte crystal included in the solid electrolyte layer includes polyphosphoric acid and the content of Li2O is 16 mol % to 25 mol % in terms of mol % on an oxide basis. |