Entropy-Assisted High-Entropy Oxide with a Spinel Structure toward High-Temperature Infrared Radiation Materials

Developing advanced materials with a high-entropy concept is one of the hot trends in materials science. The configurational entropy of high-entropy materials can be tuned by introducing different atomic species, which can also impart a result in excellent physical and chemical properties. In this work, we synthesized a solid-solution oxide (Cu, Mn, Fe, Cr)₃O₄ by a simple and scalable solid-phase synthesis method. We extensively investigated the microstructure and chemical composition, indicating that (Cu, Mn, Fe, Cr)₃O₄ has a single-phase spinel structure. Simultaneously, we reasonably evaluated the position occupied by the elements of (Cu, Mn, Fe, Cr)₃O₄ in a spinel structure as (Cu_0.75Fe_0.25)(Fe_0.25Cr_0.375Mn_0.375)₂O₄. Here, we first evaluated the infrared radiation performance of (Cu, Mn, Fe, Cr)₃O₄. The new, high-entropy oxide (HEO) (Cu, Mn, Fe, Cr)₃O₄ powder exhibits high infrared emissivity values of 0.879 and 0.848 in the wavelengths of 0.78-2.5 and 2.5-16 μm, respectively, and has excellent thermal stability. More importantly, the infrared emissivity values of as-prepared HEO coating reach 0.955 (0.78-2.5 μm) at room temperature and 0.936 (3-16 μm) at 800 °C. This work provides a viable strategy toward the laboratory mass production of this HEO for infrared radiation materials, which shows great potential in the energy-related applications.