[Task] Provided is a proton conductor and a manufacturing method thereof that are suitable for the use in a temperature range between 200° C. and 600° C.
[Solution] A proton conductor has electric conductivity of 0.01 S/cm or more at 300° C., wherein a portion of lithium ions of Li14−2xZn1+x(GeO4)4 is substituted with protons. The x is a number equal to or more than 0. 40% to 70% inclusive of movable lithium ions contained in Li14−2xZn1+x(GeO4)4 may be substituted with the protons. 50% to 60% inclusive of movable lithium ions contained in Li14−2xZn1+x as (GeO4)4 may be substituted with the protons. A manufacturing method of a proton conductor comprises a process of substituting a portion of lithium ions with protons by immersing Li14−2xZn1+x(GeO4)4 in a non-aqueous organic solvent containing acid.