Abstract: [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.

Abstract: Provided is an electrochemical cell, a power generation method using the electrochemical cell, and a manufacturing method of a hydrogen gas using the electrochemical cell that are suitable for the use in a temperature range between 200° C. and 600° C. A fuel cell 1 (electrochemical cell) includes a proton conductor 5 represented by (Li, H)14?2xZn1+x(GeO4)4 where a portion of lithium ions of Li14?2xZn1+x(GeO4)4 where x is a number equal to or more than 0 is substituted with protons, the proton conductor having electric conductivity of 0.01 S/cm or more at 300° C., an anode 6 provided on one side of the proton conductor, a cathode 7 provided on another side of the proton conductor, a first separator 9 provided on an anode side of the proton conductor to define an anode chamber 8, and a second separator 12 provided on a cathode side of the proton conductor to define a cathode chamber 11.