State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China.
Institute for Superconducting and Electronic Materials, Australian Institute of Innovative Materials, University of Wollongong, NSW, 2500, Australia.
Adv Mater. 2017 Aug;29(31). doi: 10.1002/adma.201701824. Epub 2017 Jun 19.
Antiferroelectric materials that display double ferroelectric hysteresis loops are receiving increasing attention for their superior energy storage density compared to their ferroelectric counterparts. Despite the good properties obtained in antiferroelectric La-doped Pb(Zr,Ti)O -based ceramics, lead-free alternatives are highly desired due to the environmental concerns, and AgNbO has been highlighted as a ferrielectric/antiferroelectric perovskite for energy storage applications. Enhanced energy storage performance, with recoverable energy density of 4.2 J cm and high thermal stability of the energy storage density (with minimal variation of ≤±5%) over 20-120 °C, can be achieved in Ta-modified AgNbO ceramics. It is revealed that the incorporation of Ta to the Nb site can enhance the antiferroelectricity because of the reduced polarizability of B-site cations, which is confirmed by the polarization hysteresis, dielectric tunability, and selected-area electron diffraction measurements. Additionally, Ta addition in AgNbO leads to decreased grain size and increased bulk density, increasing the dielectric breakdown strength, up to 240 kV cm versus 175 kV cm for the pure counterpart, together with the enhanced antiferroelectricity, accounting for the high energy storage density.
反铁电材料具有双铁电滞后回线，相比于铁电材料具有更高的储能密度，因此受到越来越多的关注。尽管掺镧的 Pb(Zr,Ti)O 基陶瓷中获得了良好的性能，但由于环境问题，人们非常希望使用无铅替代品，而 AgNbO 作为铁电/反铁电钙钛矿已被突出强调，可用于储能应用。在 Ta 改性的 AgNbO 陶瓷中可以实现增强的储能性能，具有可恢复的能量密度为 4.2 J cm，以及在 20-120°C 范围内储能密度的高热稳定性（变化最小为±5%）。研究表明，由于 B 位阳离子的极化率降低，Ta 掺入到 Nb 位可以增强反铁电性，这可以通过极化滞后、介电可调谐性和选区电子衍射测量来证实。此外，AgNbO 中 Ta 的添加会导致晶粒尺寸减小和体密度增加，从而提高介电击穿强度，从纯相的 175 kV cm 提高到 240 kV cm，同时增强反铁电性，从而实现高储能密度。
