The concept of high-entropy has recently emerged as a promising strategy in the development of advanced thermal barrier coating (TBC) materials. By introducing mass and size disorder through the incorporation of multiple distinct cations at a single crystallographic site in mixed oxides, high-entropy oxides (HEOs) can be designed to exhibit stabilized single-phase structures with intrinsically low thermal conductivities. In this work, we report the successful solid state synthesis and comprehensive characterization of three novel single-phase high-entropy perovskites: Ba(Ti1/5Zr1/5Hf1/5Sn1/5Mn1/5)O3, Ba(Ti1/5Zr1/5Hf1/5Sn1/5Ce1/5)O3, and Sr(Ti1/4Zr1/4Hf3/20Sn1/4Mn1/10)O3. The compounds Ba(Ti1/5Zr1/5Hf1/5Sn1/5Mn1/5)O3, Ba(Ti1/5Zr1/5Hf1/5Sn1/5Ce1/5)O3, and Sr(Ti1/4Zr1/4Hf3/20Sn1/4Mn1/10) exhibit the low thermal conductivities of approximately 1.84 Wm−1 K−1, 1.72 Wm−1 K−1, and 0.72 Wm−1 K−1, respectively, at 800 K. The Sr-based compound exhibits an ultra-low average thermal conductivity of ~ 0.63 W·m⁻1·K⁻1, which remains nearly constant over the temperature range of 300–800 K. This value corresponds to an almost 68% reduction compared to the benchmark thermal barrier coating (TBC) material, 8 mol% yttria-stabilized zirconia (8YSZ), highlighting its strong potential as a next-generation TBC candidate. The observed ultra-low, amorphous-like thermal conductivity is primarily attributed to enhanced phonon scattering induced by severe lattice distortion and high configurational entropy. Moreover, electrical characterization reveals a highly stable dielectric constant up to 200 °C, accompanied by low dielectric loss, indicating additional potential for electronic and capacitive applications. The room temperature ac conductivity for sample Ba(Ti1/5Zr1/5Hf1/5Sn1/5Mn1/5)O3, Ba(Ti1/5Zr1/5Hf1/5Sn1/5Ce1/5)O3 and Sr(Ti1/4Zr1/4Hf3/20Sn1/4Mn1/10)O3 are 1.05 × 10–6 S/m, 1.01 × 10–6 S/m and 1.63 × 10–6 S/m, respectively, at 1 kHz frequency, which shows the highly insulating nature of the samples. These findings highlight the multifunctional character of high-entropy perovskites and position them as promising candidates for thermal barrier coatings, dielectric components, and a broad range of high-temperature applications. Further investigation is warranted to fully realize and optimize their multifunctional potential.

Ultra-low thermal conductivity and dielectric stability in novel high-entropy perovskite oxides for advanced thermal and electronic applications

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发表日期：

2026年1月27日

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Rupesh Kumar,
Raj Kumar Singh,
Kumari Mamta,
Sumit Kumar Roy,
Sushil Kumar Pandey

摘要

The concept of high-entropy has recently emerged as a promising strategy in the development of advanced thermal barrier coating (TBC) materials. By introducing mass and size disorder through the incorporation of multiple distinct cations at a single crystallographic site in mixed oxides, high-entropy oxides (HEOs) can be designed to exhibit stabilized single-phase structures with intrinsically low thermal conductivities. In this work, we report the successful solid state synthesis and comprehensive characterization of three novel single-phase high-entropy perovskites: Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Mn_1/5)O₃, Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Ce_1/5)O₃, and Sr(Ti_1/4Zr_1/4Hf_3/20Sn_1/4Mn_1/10)O₃. The compounds Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Mn_1/5)O₃, Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Ce_1/5)O₃, and Sr(Ti_1/4Zr_1/4Hf_3/20Sn_1/4Mn_1/10) exhibit the low thermal conductivities of approximately 1.84 Wm⁻¹ K⁻¹, 1.72 Wm⁻¹ K⁻¹, and 0.72 Wm⁻¹ K⁻¹, respectively, at 800 K. The Sr-based compound exhibits an ultra-low average thermal conductivity of ~ 0.63 W·m⁻¹·K⁻¹, which remains nearly constant over the temperature range of 300–800 K. This value corresponds to an almost 68% reduction compared to the benchmark thermal barrier coating (TBC) material, 8 mol% yttria-stabilized zirconia (8YSZ), highlighting its strong potential as a next-generation TBC candidate. The observed ultra-low, amorphous-like thermal conductivity is primarily attributed to enhanced phonon scattering induced by severe lattice distortion and high configurational entropy. Moreover, electrical characterization reveals a highly stable dielectric constant up to 200 °C, accompanied by low dielectric loss, indicating additional potential for electronic and capacitive applications. The room temperature ac conductivity for sample Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Mn_1/5)O₃, Ba(Ti_1/5Zr_1/5Hf_1/5Sn_1/5Ce_1/5)O₃ and Sr(Ti_1/4Zr_1/4Hf_3/20Sn_1/4Mn_1/10)O₃ are 1.05 × 10^–6 S/m, 1.01 × 10^–6 S/m and 1.63 × 10^–6 S/m, respectively, at 1 kHz frequency, which shows the highly insulating nature of the samples. These findings highlight the multifunctional character of high-entropy perovskites and position them as promising candidates for thermal barrier coatings, dielectric components, and a broad range of high-temperature applications. Further investigation is warranted to fully realize and optimize their multifunctional potential.