SOLID ELECTROLYTE LAYER, ALL-SOLID-STATE SECONDARY BATTERY, AND MANUFACTURING METHOD OF SAME

A solid electrolyte layer includes a solid electrolyte and a compound represented by a composition formula MZr(PO). In the composition formula, M represents at least one selected from the group consisting of Na, K, Mg, Ca, Sr, Ba, Cu, Zn, and Ni, x satisfies 0