CaTiO3 linear dielectric ceramics with greatly enhanced dielectric strength and energy storage density
CaTiO3 linear dielectric ceramics with greatly enhanced dielectric strength and energy storage density
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DOI：
10.1111/jace.15371
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发表时间：
2018-05
影响因子：
3.9
通讯作者：
H. Zhou;X. Liu;Xiao Li Zhu;X. Chen
中科院分区：
文献类型：
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作者：
H. Zhou;X. Liu;Xiao Li Zhu;X. Chen
CaTiO_3是一种典型的高介电常数、低介电损耗、高电阻率的线性介质材料，有望成为高储能密度应用的候选材料。在前人的工作中，CaTiO_3陶瓷的能量密度为1.5×J/cm~3，介电强度仅为435×10~(-6)V/cm。事实上，CaTiO3的本征介电强度预计高达4.2 mV/cm。因此，如何通过优化CaTiO_3陶瓷的微观结构来提高其介电强度和储能密度是一个具有挑战性的问题。本文采用放电等离子烧结法制备了组织细小、均匀致密的CaTiO_3陶瓷，获得了较高的介电强度(910kV/cm)和储能密度(6.9kJ/cm3)。这可以归因于改善的电阻率和导热系数，与细小和均匀的组织有关。不同工艺制备的CaTiO_3陶瓷具有不同的击穿后特征，这很好地解释了SPS样品介电强度提高的原因。通过引入非晶态氧化铝薄膜作为电荷阻挡层，可以进一步将储能密度提高到11.8EJ/cm3，其介电强度为1188EKV/cm。
CaTiO3is a typical linear dielectric material with high dielectric constant, low dielectric loss, and high resistivity, which is expected as a promising candidate for the high energy storage density applications. In the previous work, an energy density of 1.5 J/cm3was obtained in CaTiO3ceramics, where the dielectric strength was only 435 kV/cm. In fact, the intrinsic dielectric strength of CaTiO3is predicted as high as 4.2 MV/cm. Therefore, it should be a challenge issue to enhance the dielectric strength and energy storage density of CaTiO3ceramics by optimizing the microstructures. In the present work, dense CaTiO3ceramics with fine and uniform microstructures are prepared by spark plasma sintering, and the greatly enhanced dielectric strength (910 kV/cm) and energy storage density (6.9 J/cm3) are obtained. This can be ascribed to the improved resistivity and thermal conductivity, associated with the fine and uniform microstructures. The different post‐breakdown features of CaTiO3ceramics prepared by different process well interpret why the enhanced dielectric strength is achieved in the SPS sample. The energy storage density can be further improved to 11.8 J/cm3by introducing the amorphous alumina thin films as the charge blocking layer, where the dielectric strength is 1188 kV/cm.