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<p>The escalating demand for long-term high-temperature microwave-absorbing materials (HTMAMs) in high-speed aerospace stealth is hindered by limitations such as magnetic loss degradation or oxidation risks. Herein, we introduce rare earth zirconate ceramics that exhibit air stability up to 1600 °C. Abundant oxygen vacancies significantly enhance permittivity and thus microwave-absorbing performance through activated thermionic migration at elevated temperatures. Moreover, the thermionic-facilitated permittivity can be meticulously modulated by electron delocalization, with the extent governed by lattice disorder. We demonstrate this concept through a dual-layer Er<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub>/Gd<sub>2</sub>Zr<sub>2</sub>O<sub>7</sub> structure to further optimize impedance matching, achieving an ultra-wide bandwidth (8.27 GHz) and strong absorption (−64.61 dB) at ultrathin thicknesses under 1.2 mm at 600 °C mainly by macroscopic interfacial resonance, alongside an ultralow thermal conductivity (1.61 W•m<sup>-1</sup>•K<sup>-1</sup>). This work presents an innovative approach to design high-performance and anti-oxidative HTMAMs through thermionic migration tuned by electron delocalization, advancing structural-functional integrated materials for extreme environments.</p>

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High-temperature oxide ceramic microwave absorber enabled by thermionic migration mediated by electron delocalization

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年10月16日

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  • Ruopeng Cui,
  • Zewen Duan,
  • Yi Li,
  • Xuefei Zhang,
  • Xiangyang Liu,
  • Guang Yang,
  • Lihong Yang,
  • Biao Zhao,
  • Chunlei Wan

摘要

The escalating demand for long-term high-temperature microwave-absorbing materials (HTMAMs) in high-speed aerospace stealth is hindered by limitations such as magnetic loss degradation or oxidation risks. Herein, we introduce rare earth zirconate ceramics that exhibit air stability up to 1600 °C. Abundant oxygen vacancies significantly enhance permittivity and thus microwave-absorbing performance through activated thermionic migration at elevated temperatures. Moreover, the thermionic-facilitated permittivity can be meticulously modulated by electron delocalization, with the extent governed by lattice disorder. We demonstrate this concept through a dual-layer Er2Zr2O7/Gd2Zr2O7 structure to further optimize impedance matching, achieving an ultra-wide bandwidth (8.27 GHz) and strong absorption (−64.61 dB) at ultrathin thicknesses under 1.2 mm at 600 °C mainly by macroscopic interfacial resonance, alongside an ultralow thermal conductivity (1.61 W•m-1•K-1). This work presents an innovative approach to design high-performance and anti-oxidative HTMAMs through thermionic migration tuned by electron delocalization, advancing structural-functional integrated materials for extreme environments.