High-Entropy Oxides Based on Valence Combinations: Design and Practice
19 Pages Posted: 3 Aug 2020
High-entropy oxides (HEOs) are a new class of materials promising for a wide range of applications. Designing HEOs needs to consider both geometric compatibility and electrical equilibrium. However, there is currently no available method to systematically consider these two factors when selecting constituent materials for making HEOs. Here we propose a two-step strategy, where a HEO system is first partitioned into multiple subsystems based on the valence combinations of substituted cations; the geometric compatibility is then considered in selecting suitable substituted cations. We demonstrate this strategy by using A(5B0.2)O3 perovskite as a model system. We show that the system can be partitioned into 12 subsystems. Ten of the subsystems have formed a single-phase cubic perovskite, while two have partially ordering structure. The formation of the ordering structure is mainly correlated to cation-valence difference. We anticipate that this strategy is applicable to other systems.
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