Enhanced Ni Exsolution in High-Entropy Perovskite Oxides with Broadening of Migration-Reduction Energy Landscapes.
basic_science · Level V
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- Record sourced from PubMed, PMID 42311001.
- Also identified by DOI 10.1021/acs.nanolett.6c01218.
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Abstract
While high-entropy perovskite oxides have recently emerged as promising hosts for exsolution-enabled catalysts and electrodes, a systematic understanding of how high-entropy compositions influence exsolution remains limited. Here, we compare Ni exsolution in a simpler perovskite oxide, (La<sub>0.6</sub>Sr<sub>0.4</sub>)<sub>0.95</sub>(Co<sub>0.19</sub>Fe<sub>0.76</sub>Ni<sub>0.05</sub>)O<sub>3-δ</sub> (LSCF-5Ni), and two high-entropy perovskite oxides, (La<sub>0.2</sub>Sr<sub>0.2</sub>Ca<sub>0.2</sub>Nd<sub>0.2</sub>Y<sub>0.2</sub>)<sub>0.95</sub>(Co<sub>0.19</sub>Fe<sub>0.76</sub>Ni<sub>0.05</sub>)O<sub>3-δ</sub> (CaNdY-5Ni) and (La<sub>0.2</sub>Sr<sub>0.2</sub>Ba<sub>0.2</sub>Nd<sub>0.2</sub>Y<sub>0.2</sub>)<sub>0.95</sub>(Co<sub>0.19</sub>Fe<sub>0.76</sub>Ni<sub>0.05</sub>)O<sub>3-δ</sub> (BaNdY-5Ni). The experiment reveals that the exsolved nanoparticle number density follows the order LSCF-5Ni < CaNdY-5Ni < BaNdY-5Ni, demonstrating that high-entropy configurations can enhance exsolution. To understand this trend, we develop a Monte Carlo-based modeling framework that combines a machine-learned interatomic potential to simulate representative atomic configurations and statistically evaluate possible exsolution pathways. The results show that high-entropy configurations with greater variations in A-site cation sizes (and thus greater lattice distortions) can broaden distributions of Ni migration and reduction energies, thereby creating more thermodynamically favorable exsolution pathways.