(0.96NaNbO_(3)-0.04CaZrO_(3))-xFe_(2)O_(3)反铁电陶瓷的介电及储能性能研究

Dielectric and Energy Storage Property of(0.96NaNbO_(3)-0.04CaZrO_(3))-xFe_(2)O_(3)Antiferroelectric Ceramics

0.96NaNbO_(3)-0.04CaZrO_(3)(简称NNCZ)陶瓷在室温下展现出稳定的双电滞回线,但是其储能密度、储能效率和击穿强度都比较低,限制其成为储能材料。本工作通过掺杂Fe_(2)O_(3),利用Fe^(3+)离子变价的特点,实现NNCZ储能性能的优化。采用传统固相法制备了(0.96NaNbO_(3)-0.04CaZrO_(3))-xFe_(2)O_(3)(简称NNCZ-xFe)反铁电储能陶瓷,并对样品的相结构、微观形貌、电学性能和储能性能进行了表征,重点研究了Fe_(2)O_(3)掺杂量对NNCZ陶瓷介电和储能性能的影响规律。结果表明,样品均具有单一的钙钛矿结构,掺杂Fe_(2)O_(3)能明显降低NNCZ陶瓷的烧结温度,晶粒平均尺寸随着掺杂量增大先减小后增大,掺杂量x=0.02时,晶粒平均尺寸最小(5.04μm),且具有较好的储能性能。室温下,NNCZ-0.02Fe击穿强度为230kV/cm,击穿前的有效储能密度和储能效率分别为1.57J/cm^(3)和55.74%。在125℃和外加电场180kV/cm下,NNCZ-0.02Fe的储能密度为4.53J/cm^(3)。掺杂Fe_(2)O_(3)使NNCZ陶瓷的烧成温度降低,氧空位的迁移速率下降,抑制晶粒的长大,同时降低了介电损耗,使得击穿强度增加;适量氧空位钉扎使得反铁电相向铁电相相翻转变得困难,避免出现哑铃状双电滞回线,从而提高储能效率。本研究结果表明NNCZ-xFe在电介质储能领域具有潜在应用价值。

0.96NaNbO_(3)-0.04CaZrO_(3)(NNCZ) ceramic shows stable double hysteresis loops at room temperature,but the property of energy density,energy storage efficiency and breakdown strength of NNCZ are terrible,which limitNNCZ to be used as energy storage materials.In this work,Fe_(2)O_(3) was chosen to modify the energy storage property of NNCZ.(0.96NaNbO_(3)-0.04CaZrO_(3))-xFe_(2)O_(3)(NNCZ-x Fe) antiferroelectric ceramics were prepared by traditional solid reaction method.The phase,morphology,dielectric property and energy storage property of NNCZ-x Fe were characterized.The results indicated that the crystal structures of NNCZ-x Fe ceramics were pure perovskite structure.The sintering temperature of NNCZ ceramic was decreased with addition of Fe_(2)O_(3).With the increase of Fe_(2)O_(3) content,the grain size of NNCZ-x Fe was decreased firstly and then raised.The NNCZ-0.02Fe ceramic obtained the smallest grain size (5.04μm) and the best energy storage property.The breakdown strength of NNCZ-0.02Fe was230 k V/cm at room temperature (RT).The recoverable energy density and energy storage efficiency before breakdown were 1.57 J/cm^(3) and 55.74%respectively.At 125℃and 180 kV/cm,the energy density of NNCZ-0.02Fe was 4.53 J/cm^(3).Fe_(2)O_(3) doping decreased the sintering temperature of NNCZ ceramics,reduced the the migration rate of oxygen vacancies and inhibited the growth of grains.At the same time,it reduced the dielectric loss and improved the breakdown strength.The oxygen vacancies pinning made antiferroelectric phase switch to ferroelectric phase harder,avoided appearance of dumbbell-shaped double hysteresis loops,so the energy storage efficiency was improved.This research shows that NNCZ-x Fe has a good potential application in the field of dielectric energy storage.