High entropy oxides are one of the research topicalities in the field of SOFC. However, the relationship between configuration entropy and the electrochemical properties of these materials is not well understood. Here, a medium entropy material (La 0.2 Pr 0.2 Nd 0.2 Sm 0.2 Eu 0.2 ) 2 CuO 4 ((Ln 0.2 ) 2 CuO 4 ) derived from Nd 2 CuO 4 material is designed. It was found that increasing the configuration entropy of the A-site promotes the production of highly reactive/concentrated non-stoichiometric oxygen and increases the covalency of the Cu3d-O2p orbital. The polarization impedance of (Ln 0.2 ) 2 CuO 4 is 0.92 Ω cm 2 at 700 °C, which is smaller than that of Nd 2 CuO 4 (1.8 Ω cm 2 at 700 °C). The peak power density of single cells NiO-YSZ|YSZ|GDC|cathode is 526 mW cm −2 at 700 °C within 60 h of stable operation at 0.5 V. First-principles calculations demonstrate that (Ln 0.2 ) 2 CuO 4 has lower charge transfer energy, which promotes the electronic conduction. Furthermore, the dissociation energy of adsorbed oxygen (O ad ) on the surface of (Ln 0.2 ) 2 CuO 4 is 2.24 eV, which is smaller than that of Nd 2 CuO 4 (2.26 eV). These results suggest that the entropy-increasing strategy can enhance the electrocatalytic performance.
Nie Yujia,Qian Guangren,Chen Youdong,He Jia,Zhou Wei,Xiao Hanning
The proton ceramic fuel cell (PCFC) is a cutting-edge technology for achieving carbon-free and efficient energy conversion. It has garnered significant attention in the clean energy sector due to its environmental adaptability and fuel compatibility in the low to medium temperature range of 500 to 700 °C. The intrinsic properties of cathode materials significantly affect the electrochemical performance of PCFC. In this study, a novel Sc-doped La 0.6 Sr 0.4 CoO 3−δ cathode was designed and synthesized using the sol–gel method, and its electrochemical performance in the PCFC was systematically investigated. Test results under hydrogen fuel conditions demonstrated that the single cell using the La 0.6 Sr 0.4 Sc 0.4 Co 0.6 O 3−δ cathode exhibited a respectable power output capability at 700 °C, achieving a peak power density (PPD) of 556 mW cm −2 and polarization impedance of 0.217 Ω cm 2 . Notably, the cell exhibited a performance degradation rate as low as 0.013% h −1 after 100 h of operation at a constant current discharge of 342 mA cm −2 , with the open-circuit voltage and PPD maintaining 98.5% and 107% of their initial values, respectively. This study provides valuable reference for the design of perovskite cathodes for PCFC.
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