Scholarlink

<p>This work highlighted the effect of microstructure on the dielectric, ferroelectric, and energy storage properties of NaNbO<sub>3</sub> ceramics. The microstructure of NaNbO<sub>3</sub> ceramics is tailored by varying the sintering time (S<sub>T</sub>) from 2 to 10&#xa0;h and an optimum relative density of 97% is obtained for S<sub>T</sub> of 8&#xa0;h. The X-ray diffraction (XRD) analysis confirms the formation of pure NaNbO<sub>3</sub> with an orthorhombic structure. The Raman analysis further revealed the coexistence of the ferroelectric (FE) Q phase (P2<sub>1</sub>ma) and the anti-FE (AFE) P phase (Pbma) at room temperature. Scanning electron microscopy micrographs revealed the presence of uniform grains with optimum and relatively large grain size of 9.14&#xa0;μm at S<sub>T</sub> of 8&#xa0;h and the energy dispersive X-ray spectroscopy analysis confirmed the stoichiometric ratio of NaNbO<sub>3</sub> ceramics. The variation in grain size with S<sub>T</sub> is explained based on mechanism of coalescence and Ostwald ripening. The temperature-dependent dielectric measurements exhibited a small peak in the region of 140–180&#xa0;°C that corresponds to the phase transition from FE Q phase to AFE P phase and a sharp peak in the range of 360–390&#xa0;°C that corresponds to the Curie temperature. The optimum dielectric properties such as dielectric constant &#xa0;of&#xa0;~ 398 and dielectric loss of 0.0467 were obtained in the ceramics sintered at 8&#xa0;h and are attributed to high bulk density. The P–E hysteresis of NaNbO<sub>3</sub> ceramics exhibited a typical ferroelectric loop due to the field-induced AFE-FE phase transition as evidenced from XRD analysis of poled and un-poled ceramics. The saturation polarization (P<sub>s</sub>) and remnant polarization (P<sub>r</sub>) increased with increasing S<sub>T</sub> in the range 2 to 8&#xa0;h, and maximum P<sub>s</sub> of 30.61 μC/cm<sup>2</sup> was obtained for 8&#xa0;h sintered NaNbO<sub>3</sub> ceramic and is attributed to optimum grain size and relative high density. Further, lower coercive field (E<sub>c</sub>) of 41.25&#xa0;kV/cm and low back switching ratio at S<sub>T</sub> = 8&#xa0;h confirm the&#xa0;presence of more 180° domains. Moreover, the NaNbO<sub>3</sub> ceramics exhibited an optimal energy storage performance with a recoverable energy density (W<sub>rec</sub>) of 457.7&#xa0;mJ/cm<sup>3</sup>. Additionally, they exhibited an excellent frequency stability up to 500&#xa0;Hz, thermal stability up to 270&#xa0;°C, and fatigue-free P–E loops up to 10<sup>5</sup> cycles.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effect of microstructure tailoring on dielectric, ferroelectric, and energy storage properties of NaNbO3 ceramics

  • 期刊论文

  • 发表日期：

    2025年9月22日

查看全文
  • P. Madhushree,
  • N. S. Kiran Kumar,
  • B. D. S. Chandana,
  • Fabrício Luiz Faita,
  • Navneet Dabra,
  • K. C. Sekhar

摘要

This work highlighted the effect of microstructure on the dielectric, ferroelectric, and energy storage properties of NaNbO3 ceramics. The microstructure of NaNbO3 ceramics is tailored by varying the sintering time (ST) from 2 to 10 h and an optimum relative density of 97% is obtained for ST of 8 h. The X-ray diffraction (XRD) analysis confirms the formation of pure NaNbO3 with an orthorhombic structure. The Raman analysis further revealed the coexistence of the ferroelectric (FE) Q phase (P21ma) and the anti-FE (AFE) P phase (Pbma) at room temperature. Scanning electron microscopy micrographs revealed the presence of uniform grains with optimum and relatively large grain size of 9.14 μm at ST of 8 h and the energy dispersive X-ray spectroscopy analysis confirmed the stoichiometric ratio of NaNbO3 ceramics. The variation in grain size with ST is explained based on mechanism of coalescence and Ostwald ripening. The temperature-dependent dielectric measurements exhibited a small peak in the region of 140–180 °C that corresponds to the phase transition from FE Q phase to AFE P phase and a sharp peak in the range of 360–390 °C that corresponds to the Curie temperature. The optimum dielectric properties such as dielectric constant  of ~ 398 and dielectric loss of 0.0467 were obtained in the ceramics sintered at 8 h and are attributed to high bulk density. The P–E hysteresis of NaNbO3 ceramics exhibited a typical ferroelectric loop due to the field-induced AFE-FE phase transition as evidenced from XRD analysis of poled and un-poled ceramics. The saturation polarization (Ps) and remnant polarization (Pr) increased with increasing ST in the range 2 to 8 h, and maximum Ps of 30.61 μC/cm2 was obtained for 8 h sintered NaNbO3 ceramic and is attributed to optimum grain size and relative high density. Further, lower coercive field (Ec) of 41.25 kV/cm and low back switching ratio at ST = 8 h confirm the presence of more 180° domains. Moreover, the NaNbO3 ceramics exhibited an optimal energy storage performance with a recoverable energy density (Wrec) of 457.7 mJ/cm3. Additionally, they exhibited an excellent frequency stability up to 500 Hz, thermal stability up to 270 °C, and fatigue-free P–E loops up to 105 cycles.