A novel high-entropy (Y0.2La0.2Er0.2Ho0.2Tm0.2)6MoO12 ceramic nanofibers with high near-infrared reflection and low thermal conductivity

In high temperature industrial applications, aerospace and building energy efficiency sectors, the thermal protection provided by insulation materials under extreme environmental conditions is critical. This study successfully prepared a novel rare earth high entropy molybdate (Y 0.2 La 0.2 Er 0.2 Ho 0.2 Tm 0.2 ) 6 MoO 12 ceramic nanofibers ((5RE) 6 MoO 12 ) whit high near-infrared reflectivity and low thermal conductivity by electrostatic spinning method. The spectral reflectance studies revealed that (5RE) 6 MoO 12 nanofibers exhibit a high reflectance of 99.2 % in the near-infrared wavelength range. The high entropy induced lattice distortion effect enhances phonon scattering, resulting in the thermal conductivity of (5RE) 6 MoO 12 nanofiber-based ceramics (0.0689 W/m·K, 25℃) being lower than that of single-phase Y 6 MoO 12 nanofiber-based ceramics (0.0832 W/m·K, 25℃). Additionally, upon heat treatment between 800 and 1100℃, the (5RE) 6 MoO 12 fibers demonstrated slower grain growth and better fiber structure retention than Y 6 MoO 12 fibers attributed to the hysteretic diffusion effect of high entropy, which allowed (5RE) 6 MoO 12 ceramic nanofibers to exhibit better thermal stability. These outstanding properties make high-entropy ceramic nanofibers a promising candidate for application in the field of thermal insulation materials.