不同结晶时间对PbO-BaO-Na_2O-Nb_2O_5-SiO_2体系玻璃陶瓷介电性能与储能性能的影响研究

Dielectric Properties and Energy Storage Properties of PbO-BaO-Na_2O-Nb_2O_5-SiO_2 Glass-Ceramics with Different Crystallization Time

玻璃陶瓷材料具有优异的介电特性与耐击穿特性,是一种极具潜力的高储能密度介电材料。介电陶瓷的微观结构尤其是纳米尺度的陶瓷晶粒对材料的介电特性有着显著影响。本文利用可控结晶技术,通过改变结晶时间(1~1000 min),制备一系列微观结构逐渐改变的玻璃陶瓷纳米复合材料。X射线衍射(XRD)与透射电镜(TEM)结果表明,随着结晶时间由1 min增加至1000 min,Pb O-Ba O-Na2O-Nb2O5-Si O2(PBNNS)体系玻璃陶瓷的晶粒尺寸由几十纳米增大到几百纳米,但结晶相几乎没有变化。介电特性研究结果表明,PBNNS玻璃陶瓷的介电常数及其温度稳定性、电场稳定性均强烈依赖于结晶时间;PBNNS玻璃陶瓷的极化曲线随着结晶时间增加呈现铁电极化趋势。此外,对极化曲线的计算结果表明,样品的能量密度随结晶时间逐渐增加,而能量释放效率逐渐降低;结晶时间为1 min的样品能量释放效率最高,达到87.8%,这可能是由于PBNNS玻璃陶瓷中存在较弱的界面极化行为所致。

Glass-ceramic is a kind of excellent candidate materials for high energy storage application,which has outstanding dielectric properties and high breakdown strength.Recent reports indicated that the microstructures of dielectric ceramics especially their nano-scale ceramic grains influenced the dielectric properties significantly.In this paper,a series of PbO-BaO-Na2O-Nb2O5-SiO2（PBNNS） glass-ceramics were prepared via controlled crystallization by varying the crystallization time from 1 to 1000 min.X-ray diffraction（XRD） and transmission electron microscope（TEM） indicated that grain sizes of crystallized ceramic phases increased from dozens to hundreds of nanometers,but the ceramic phases were not changed.Dielectric properties of PBNNS glass-ceramics were investigated.The permittivity and their stability of temperature and electric field were all dependent on crystallization time strongly,and the polarization curves gradually changed with the time increasing.In addition,the energy density increased with the crystallization time increasing and the energy efficiency decreased gradually.The maximum energy efficiency of 87.8% was obtained in the sample with crystallization time of 1 min,which might be attributed to low interfacial polarization in PBNNS glass-ceramics.