Solid Oxide Cells with Phase-Inversion Tape-Casted Hydrogen Electrode and SrSc 0.175 Nb 0.025 Co 0.8 O 3-δ Oxygen Electrode for High-Performance Reversible Power Generation and Hydrogen Production.

Solid oxide cells (SOCs) have been considered as a promising energy conversion and storage device. However, state-of-the-art cells' practical application with conventionally fabricated Ni-(Y 2 O 3 ) 0.08 (ZrO 2 ) 0.92 (YSZ) cermet hydrogen electrode and La 0.8 Sr 0.2 MnO 3 perovskite oxygen electrode is strongly limited by the unsatisfactory performance. Instead, new advances in cell materials and fabrication techniques that can lead to significant performance enhancements are urgently demanded. Here, we report a high-performance reversible SOC that consisted of a combination of SrSc 0.175 Nb 0.025 Co 0.8 O 3-δ (SSNC) and phase-inversion tape-casted Ni-YSZ, which served as the oxygen and hydrogen electrode, respectively. The hydrogen electrode synthesized from phase-inversion tape-casting showed a high porosity of 60.8%, providing sufficient active sites for hydrogen oxidation in the solid oxide fuel cell (SOFC) mode and H 2 O electrolysis in the solid oxide electrolysis cell (SOEC) mode. Accordingly, it was observed that the maximum power density of 2.3 W cm -2 was attained at 750 °C in SOFC mode and a current density of -1.59 A cm -2 was obtained at 1.3 V in SOEC mode. Hence, these results reveal that the simultaneous optimization of oxygen and hydrogen electrodes is a pragmatic strategy that improves the performance of SOCs, which may significantly accelerate the commercialization of such an attractive technology.