Solid Oxide Cells with Phase-Inversion Tape-Casted Hydrogen Electrode and SrSc_0.175Nb_0.025Co_0.8O_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-(Y₂O₃)_0.08(ZrO₂)_0.92 (YSZ) cermet hydrogen electrode and La_0.8Sr_0.2MnO₃ 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_0.175Nb_0.025Co_0.8O_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 H₂O 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.