High-entropy rare earth stannate ceramics: Acid corrosion resistant radiative cooling materials with high atmospheric transparency window emissivity and high near-infrared solar reflectivity

In response to the development of the concepts of “carbon neutrality” and “carbon peak”, it is critical to developing materials with high near-infrared (NIR) solar reflectivity and high emissivity in the atmospheric transparency window (ATW; 8–13 μm) to advance zero energy consumption radiative cooling technology. To regulate emission and reflection properties, a series of high-entropy rare earth stannate ceramics (HE-RE2Sn2O7: (Y0.2La0.2Nd0.2Eu0.2Gd0.2)2Sn2O7, (Y0.2La0.2Sm0.2Eu0.2Lu0.2)2Sn2O7, and (Y0.2La0.2Gd0.2Yb0.2Lu0.2)2Sn2O7) with severe lattice distortion were prepared using a solid phase reaction followed by a pressureless sintering method for the first time. Lattice distortion is accomplished by introducing rare earth elements with different cation radii and mass. The as-synthesized HE-RE2Sn2O7 ceramics possess high ATW emissivity (91.38%–95.41%), high NIR solar reflectivity (92.74%–97.62%), low thermal conductivity (1.080–1.619 W·m−1·K−1), and excellent chemical stability. On the one hand, the lattice distortion intensifies the asymmetry of the structural unit to cause a notable alteration in the electric dipole moment, ultimately enlarging the ATW emissivity. On the other hand, by selecting difficult excitation elements, HE-RE2Sn2O7, which has a wide band gap (Eg), exhibits high NIR solar reflectivity. Hence, the multi-component design can effectively enhance radiative cooling ability of HE-RE2Sn2O7 and provide a novel strategy for developing radiative cooling materials.