Under the intermediate-to-low temperature conditions, the operational efficiency of solid oxide cells (SOCs) is considerably constrained by sluggish kinetics of the oxygen electrode reaction, particularly with respect to the bulk oxygen transport. To address this challenge, a trace introduction of high-valent vanadium ions at the B-site is carried out, which generates the additional bulk oxygen vacancies, thereby enhancing the oxygen ion transport pathways in the electrode. As a result, SrCo 0.7 Fe 0.275 V 0.025 O 3-δ (SCFV 0.025 ) demonstrates accelerated oxygen ion transport kinetics, which can be attributed to the reduced formation energy of bulk oxygen vacancies. It achieves an area-specific resistance of just 0.021 Ω cm 2 at 650 °C, as well as a peak power density of 1.3 W cm −2 and an electrolysis current density of −1.1 A cm −2 at 1.3 V for button cell. In addition, the large-area single cell exhibits the high power of 32.7 W and the electrolysis current of 58.5 A at 750 °C. The effective strategy reports in this work provides a novel perspective for improving oxygen electrodes for SOCs. Trace vanadium doping enhances the formation of additional oxygen vacancies in the bulk, promoting a more uniform distribution of oxygen vacancies that has high conductivity, modified thermal expansion behavior, and excellent oxygen transport capability. In addition, both the button and large-area single cell (10 × 10 cm 2 ) demonstrated superior electrochemical performance. • Trace vanadium doping increases additional oxygen vacancies. • Additional bulk oxygen vacancies enhance oxygen ion transport. • Lowering of the operating temperature for solid oxide cells. • Application of oxygen electrodes in button cell and large-area single cell.
Chen et al. (Fri,) studied this question.