Solid Oxide Electrolysis for Hydrogen Production: From Oxygen Ion to Proton Conducting Cells

Electrochemical splitting of water, using solid oxide electrolysis cells (SOEC), offers an economic and efficient pathway for large-scale hydrogen production that not only utilizes renewable energy but also allows both distributed and centralized hydrogen production to accelerate and enable hydrogen infrastructure for mobility. In this technical contribution, two types of electrochemical systems using conventional oxygen ion conducting (O-SOEC) and newly developed proton conducting (P-SEOC) has been compared in terms of hydrogen purity, electrochemical performance, and stability (structural and electrochemical). The observations on dopant exsolution, solid-solid (electrode/electrolyte interface) and solid-gas (electrode-H2O, O2, and H2) interactions have been presented. The composition, structure, and morphology changes and their roles on electrochemical performance and electrode stability in oxidizing (O2) and reducing (H2) atmospheres has been discussed.