Steam Electrolysis Using LaGaO3 Based Perovskite Electrolyte for Recovery of Unused Heat Energy

Application of LaGaO 3 based electrolyte for steam electrolysis was studied for the useful utilization of unused heat energy from steelmaking process.It was found that the H 2 formation rate almost obeys the Faraday's law suggesting unity of oxide ion transport number in LaGaO 3 perovskite under an electrolysis condition up to 2.0 V applied potential.Among the examined cathode catalyst, nickel shows the smallest cathodic overpotential and the addition of Fe to Ni is highly effective for increasing the H 2 formation rate in the steam electrolysis at 873 K.The highest H 2 formation rate is obtained at the composition of Ni : Feϭ9 : 1.Short stack of the steam electrolysis cell consisting of 25 cells in series connection was also studied and the formation rate of H 2 was achieved as large as 70 L/min at 1.8 V applied potential.Heat balance was calculated based on the developed stack level.It became clear that the heat source of 223 K level is enough for sustaining cell temperature because of large Joule heat.