 The electrolyte must be dense enough that the steam and hydrogen gas cannot diffuse through and lead to the recombination of the H2 and O2−.At the electrolyte-anode interface, the oxygen ions are oxidized to form pure oxygen gas, which is collected at the surface of the anode.Solid oxide electrolyzer cells follow the same construction of a solid-oxide fuel cell, consisting of a fuel electrode (cathode), an oxygen electrode (anode) and a solid-oxide electrolyte.