Feng Wenbin, Ding Lele, Zhang Jiajia, Zhu Chunyi, Song Shenzhenyi
Jiangsu Key Laboratory of Zero-Carbon Energy Development and System Integration, School of Environmental Science, Nanjing Xiaozhuang University Nanjing 211171 China
RSC Adv. 2024 Nov 4;14(47):35064-35073. doi: 10.1039/d4ra06275b. eCollection 2024 Oct 29.
Dielectric capacitors are widely used in the field of pulsed power systems owing to their ultra-fast charge and discharge capacity; however, considering the complex environment they face in practical applications, how to further improve their thermal stability is an urgent issue that needs to be solved. Tungsten bronzes have the potential to broaden the temperature stability range owing to their unique structure, but only few studies have focused on them. Herein, lead-free Sr La NaHf Nb O ceramics with a tungsten bronze structure were synthesized, and their energy storage properties were comprehensively characterized. With proper Hf substitution in the B site and rare earth substitution in the A site, significantly enhanced relaxor behavior is induced, leading to a broad plateau of the dielectric curve, slim polarization-electric field loop, high energy storage efficiency and stable capacitive performance over a wide temperature range. In addition, an improved microstructure with fewer defects, decreased average grain size, increased band gap and resistance were obtained, which benefit to the increase in breakdown strength and energy storage density. Finally, improved energy storage performance and thermal stability were achieved for the compounds, with = 3.6 J cm, = 2.9 J cm, = 80% and stable temperature range = 20-160 °C. Thus, the current system is a promising candidate for application in temperature-stable dielectric capacitors.
介电电容器因其超快的充放电能力而在脉冲功率系统领域得到广泛应用；然而，考虑到它们在实际应用中面临的复杂环境，如何进一步提高其热稳定性是一个亟待解决的问题。钨青铜因其独特的结构有潜力拓宽温度稳定范围，但仅有少数研究关注它们。在此，合成了具有钨青铜结构的无铅SrLaNaHfNbO陶瓷，并对其储能性能进行了全面表征。通过在B位进行适当的Hf取代和在A位进行稀土取代，诱导出显著增强的弛豫行为，导致介电曲线出现宽平台、极化-电场回线变窄、储能效率高且在宽温度范围内电容性能稳定。此外，获得了缺陷更少、平均晶粒尺寸减小、带隙和电阻增加的改进微观结构，这有利于提高击穿强度和储能密度。最终，该化合物实现了改进的储能性能和热稳定性，其中=3.6J/cm，=2.9J/cm，=80%，稳定温度范围为20-160°C。因此，当前体系是应用于温度稳定介电电容器的有前途的候选材料。
