Modified by Sm0.2Ce0.8O2−δ (SDC) nanoparticles (NPs), SmBaCo2O5+δ (SBCO) double perovskite oxide is evaluated as a promising cathode material for intermediate temperature solid oxide fuel cells. The SDC NPs are epitaxially grown on the surface of SBCO with (220) planes of SDC aligning smoothly to (020) or (100) planes of SBCO, forming a tight, coherent connection at the interface. The influence of this modification on thermal expansion, oxygen diffusion, electrical conductivity and electrochemical properties is investigated thoroughly in this work. The designed SBCO–SDC cathode material demonstrates a lower thermal expansion coefficient (TEC), ∼16.4 × 10−6 K−1, than that of the unmodified SBCO, ∼20.9 × 10−6 K−1. While SDC coating results in a decreased total electrical conductivity, it facilitates oxygen bulk diffusion and improves the surface exchange reaction kinetics. Coating with SDC NPs can accelerate the rate-determining process of dissociation of the absorbed molecular oxygen, especially at intermediate temperatures. Accordingly, the constructed symmetrical cell with the La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) electrolyte shows lower polarization resistance values, if the SBCO–SDC cathode is utilized. Also, the LSGM electrolyte-supported (300 μm) full cell is found to deliver a high power density of 800 mW cm−2 at 800 °C. Owing to the strong and coherent interfacial connection, the developed cathode demonstrates a relatively steady electrochemical performance.
Yi Lu,Tianyi Dai,Chunhua Lu,Cancan Cao,Weijie Zhang,Weifeng Xu,Huihua Min,Xiaofei Yang
As a promising solar-thermal energy conversion system, solar-driven vapor generation has been considered as a potential strategy to mitigate freshwater shortage and water contamination . Although remarkable advances have been achieved in this emerging field, the majority of solar evaporators that have been explored suffer from high cost, tedious synthetic protocols, and low robustness. Herein we demonstrate a facile two-step strategy for the synthesis of doped SmBaCo 2 O 5+δ double perovskites by combining a sol-gel approach with high-temperature annealing. It is noteworthy that as-prepared double perovskites exhibit an outstanding broadband solar absorption of 93% as well as a relatively low thermal radiation loss compared to conventional carbon-based sunlight absorbers. The constructed double perovskite-based interfacial solar steam device reveals an impressive evaporation efficiency of 86% at a power density of 2 W/cm 2 . Therefore, the explored solar evaporation system based on double perovskites Sm 0.7 Sr 0.3 BaCo 2 O 5+δ offers a complementary approach for large-scale fabrication, high-reliability, and superior performance solar-to-thermal energy conversion systems.
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