Electrochemically Assisted Construction of a La₂NiO_4+δ@Pt Core–Shell Structure for Enhancing the Performance and Durability of La₂NiO_4+δ Cathodes

Ruddlesden–Popper oxide La2NiO4+δ (LNO) has a high ionic conductivity and good thermal match with the electrolyte of solid oxide fuel cells (SOFCs); however, LNO suffers from performance decay owing to the La surface segregation under the operation conditions of SOFCs. Herein, we report an in situ electrochemical decoration strategy to improve the electrocatalytic activity and durability of LNO cathodes. We show that the electrochemical polarization leads to in situ construction of the LNO@Pt core–shell structure, significantly suppressing the detrimental effect of La surface segregation on the LNO cathode. The initial peak power density of a single cell with the LNO cathode is 0.71 W cm–2 at 750 °C, increasing to 1.39 W cm–2 by the in situ construction of the LNO@Pt core–shell structure after polarization at 0.5 A cm–2 for 20 h. The LNO@Pt core–shell structure is also highly durable without noticeable performance degradation over the duration of the test for 180 h. The findings shed light on the design and fabrication of highly active and durable LNO-based cathodes for SOFCs

Ultrafine, Dual-Phase, Cation-Deficient PrBa_0.8Ca_0.2Co₂O_5+δ Air Electrode for Efficient Solid Oxide Cells

Nanostructured air electrodes play a crucial role in improving the electrocatalytic activity of oxygen reduction and evolution reactions in solid oxide cells (SOCs). Herein, we report the fabrication of a nanostructured BaCoO3-decorated cation-deficient PrBa0.8Ca0.2Co2O5+δ (PBCC) air electrode via a combined modification and direct assembly approach. The modification approach endows the dual-phase air electrode with a large surface area and abundant oxygen vacancies. An intimate air electrode–electrolyte interface is in situ constructed with the formation of a catalytically active Co3O4 bridging layer via electrochemical polarization. The corresponding single cell exhibits a peak power density of 2.08 W cm–2, an electrolysis current density of 1.36 A cm–2 at 1.3 V, and a good operating stability at 750 °C for 100 h. This study provides insights into the rational design and facile utilization of an active and stable nanostructured air electrode of SOCs