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: (Y_0.2La_0.2Nd_0.2Eu_0.2Gd_0.2)₂Sn₂O₇, (Y_0.2La_0.2Sm_0.2Eu_0.2Lu_0.2)₂Sn₂O₇, and (Y_0.2La_0.2Gd_0.2Yb_0.2Lu_0.2)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 (E_g), 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.