Patent ID: 7955530

Claim:
An ionic conductor characterized by comprising oxygen defects and metal defects in a cryolite lattice, wherein the ionic conductor comprises a metal composite oxide represented by the following Formula 1 or the following Formula 2: [Formula 1] Sr 12−x B 4 O 21±δ C z (I) wherein B is at least one element selected from the group consisting of Ta and Nb; C is at least one anion selected from the group consisting of S and halogen atoms, or H + cation; x is a decimal ranging from 0.8 to 1.2 (0.8≦x≦1.2); δ is a decimal ranging from 0 to 3 (0.1≦δ≦3); and z is a decimal ranging from 0 to 7 (0≦z≦7), [Formula 2] Sr 11−x+y A x B 4 O 24-δ C z (II) wherein A is at least one element selected from the group consisting of La, Ba and Y; B is at least one element selected from the group consisting of Ta and Nb; C is at least one anion selected from the group consisting of S and halogen atoms, or H + cation; x is a decimal greater than 0 and less than or equal to 3 (0<x≦3); y is a decimal ranging from −1 to 1 (−1≦x≦1); δ is a decimal ranging from 0 to 3 (0≦δ≦3); and z is a decimal ranging from 0 to 7 (0≦z≦7).