Mechanism of enhanced energy storage density in AgNbO3-based lead-free antiferroelectrics
Mechanism of enhanced energy storage density in AgNbO3-based lead-free antiferroelectrics
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DOI：
10.1016/j.nanoen.2020.105423
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发表时间：
2021-01-01
期刊：
影响因子：
17.6
通讯作者：
Reaney, Ian M.
中科院分区：
文献类型：
--
作者：
Lu, Zhilun;Bao, Weichao;Reaney, Ian M.
研究了无铅Ag_（1 - 3）Nd_xTayNb_（1-y）O_3反铁电陶瓷的高储能密度的机理。Rietveld对原位同步辐射X射线数据的改进表明，该结构在电场（E）下保持四倍和正交晶系，但采用非中心对称空间群Pmc 21，其中阳离子表现出铁电构型。Nd和Ta掺杂都稳定了AFE结构，从而将AFE铁电开关场从150 kV cm（-1）增加到350 kV cm（-1）。畴尺寸和AFE/铁电体耦合的相关长度随着Nd掺杂而减小，从而导致更细的磁滞回线。最大极化（P-max）通过A位异价掺杂来优化，这也降低了电导率，允许应用更大的E。这些效应联合收割机提高了能量存储密度，对于Ag 0.97 Nd 0.01 Ta 0.20 Nb 0.80 O3，W-rec = 6.5 J cm（-3）。
The mechanisms underpinning high energy storage density in lead-free Ag1-3xNdxTayNb1-yO3 antiferroelectric (AFE) ceramics have been investigated. Rietveld refinements of in-situ synchrotron X-ray data reveal that the structure remains quadrupled and orthorhombic under electric field (E) but adopts a non-centrosymmetric space group, Pmc21, in which the cations exhibit a ferrielectric configuration. Nd and Ta doping both stabilize the AFE structure, thereby increasing the AFE-ferrielectric switching field from 150 to 350 kV cm(-1). Domain size and correlation length of AFE/ferrielectric coupling reduce with Nd doping, leading to slimmer hysteresis loops. The maximum polarization (P-max) is optimized through A-site aliovalent doping which also decreases electrical conductivity, permitting the application of a larger E. These effects combine to enhance energy storage density to give W-rec = 6.5 J cm(-3) for Ag0.97Nd0.01Ta0.20Nb0.80O3.