摘要
高功率、高能量密度的介质储能电容器在脉冲功率系统小型化和轻量化的过程中具有重要意义。采用固相反应法制备了无铅改性的Sr_(0.7)Bi_(0.2)TiO_(3)(SBT)基储能陶瓷,研究了掺杂不同含量ZrO_(2)对该陶瓷的相结构、微观结构、介电性能、铁电性能、击穿机制的影响。结果表明:Zr元素部分以Zr^(4+)形式溶解于SBT晶格中,其余以ZrO_(2)形式存在晶界和晶粒表面;储能密度的提升主要依赖于介电击穿强度(Eb)的增强,可能的物理机制,包括晶粒尺寸、带隙、阻抗和激活能等,协同促进了Eb的提高。在所研究的材料中,SBT–2%(质量分数)ZrO_(2)陶瓷具有最好的储能性能,可恢复储能密度Wrec=5.57 J/cm^(3),能量效率η=88.97%;即使在经过5×10^(4)次循环后也能表现出良好的性能稳定性(W_(rec)变化幅度<1%),是一种非常有前景的脉冲功率储能电容器候选材料。
Introduction Dielectric ceramic capacitors are essential components in next-generation advanced pulse power systems due to their ultra-fast charging/discharging rates and remarkable power density.As a typical lead-free perovskite material,Sr_(0.7)Bi_(0.2)TiO_(3)(SBT)has a larger permittivity rather than SrTiO3 because Bi modification favors producing a high polarization due to the intense hybridization between the 6s2 orbitals of Bi^(3+)and O 2p orbitals.Moreover,it also has a superior ferroelectric relaxor behavior with a diffused maximum dielectric constant in a wide temperature range,benefiting from Bi^(3+)off centering and Sr site vacancies.However,SBT ceramic still has a critical challenge for improving dielectric breakdown strength(Eb).Some previous studies indicate that adding some oxides can effectively inhibit grain growth and increase Eb.In this paper,the SBT ceramics were synthesized by a conventional solid-state sintering method with ZrO_(2)as an additive.A part of Zr^(4+)was deposited on the grain boundary in the form of oxides to inhibit grain growth.The breakdown strength and the energy storage density of the ceramics with different ZrO_(2)contents were analyzed.Materials and method Bi2O3(99.5%,in mass.The same below),SrCO_(3)(99.5%),TiO_(2)(99.8%),and ZrO_(2)(99.9%)were used as raw materials.The raw materials were weighed according to the stoichiometric ratio.The materials were mixed with anhydrous ethanol and ground in a ball mill with zirconium balls for 12 h.The slurry was dried in an oven.After pre-firing at 850℃for 5 h,the powder was further ground for 24 h according to the corresponding mass ratio Sr_(0.7)Bi_(0.2)TiO_(3)+xZrO_(2)(SBT–xZr,x=0,0.5%,1.0%,2.0%,5.0%,in mass fraction).The dried ground powder was pressed into sheets with a thickness of 0.8 mm and a diameter of 12 mm,and then sintered at a rate of 4℃/min at 1200–1250℃for 3 h,and then cooled down naturally.Results and discussion Based on the XRD patterns and mapping energy spectra,element Zr partially dissolves in the SBT l
作者
刘建博
郑鹏
白王峰
盛林生
LIU Jianbo;ZHENG Peng;BAI Wangfeng;SHENG Linsheng(Lab for Nanoelectronics and Nanoelectronic Devices,Department of Electronics Science and Technology,Hangzhou Dianzi University,Hangzhou 310018,China;Key Laboratory of Novel Materials for Sensor of Zhejiang Province,Hangzhou Dianzi University,Hangzhou 310012,China;College of Information Engineering,Jiaxing Nanhu University,Jiaxing 314001,Zhejiang,China)
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2024年第4期1345-1354,共10页
Journal of The Chinese Ceramic Society
基金
浙江省自然科学基金(LY22E020006,LQ22A040012)。
关键词
钛酸锶铋基陶瓷
储能
介电击穿强度
物理机制
strontium bismuth titanate based ceramics
energy storage
dielectric breakdown strength
physical mechanisms
