| 摘要 |
Provided is a complex oxide that exhibits suitable proton conductivity, has a high hydrogen content, and contains almost no impurity phase. The complex oxide is represented by chemical formula Li7-xHxLa3M2O12 (M represents Zr and/or Hf, 3.2<x≤7), and is a monophase of a garnet-type structure belonging to the cubic crystal system. The method for producing this complex oxide involves an exchange step in which a starting-material complex oxide represented by chemical formula Li7-xHxLa3M2O12 (M represents Zr and/or Hf, 0≤x≤3.2) contacts a compound having a hydroxy group or a carboxyl group, and at least some of the lithium in the starting-material complex oxide is exchanged for hydrogen from the compound having the hydroxy or carboxyl group. |
