Novel A(Mn0.2Fe0.2Co0.2Ni0.2Cu0.2)O3 (A=La,Y) high-entropy perovskite ceramics with infrared radiation properties at high temperature

Infrared radiation materials occupy an important position in energy saving of industrial furnaces and thermal protection of spacecraft, but the existing IR radiation materials can hardly satisfy the dual requirements of high emissivity in a wide band and excellent thermal stability at the same time. Here, high-entropy perovskite oxides A(Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 )O 3 (A = La, Y) are prepared using solid-phase synthesis. The introduction of the high-entropy design provides the cationic valence behavior, increases oxygen vacancy concentration and reduces the symmetry of the lattice vibration, thus narrowing the band gap, increasing the free carrier concentration, and improving the lattice vibration. This enhances the material's intrinsic absorption, carrier absorption, and lattice vibration absorption, ultimately resulting in a material with high emissivity in a wide band. Among them, La(Mn 0.2 Fe 0.2 Co 0.2 Ni 0.2 Cu 0.2 )O 3 shows an emissivity of 0.864 at 0.78–3 μm and 0.855 at 3–8 μm, respectively. Moreover, it exhibits stronger thermal stability, and its emissivity shows an upward trend with the increase of temperature, which highlights the key role of A-site cations in regulating lattice distortion and defect dynamics. This work provides a new paradigm for designing materials with IR radiation performance for service in high-temperature environments.