Dielectric ceramic capacitors are critical components in modern electronics and pulsed power systems, prized for their ultra-fast charge–discharge capabilities and high-power density. However, their real-world application has been constrained by modest recoverable energy storage density (Wrec) and energy efficiency (η), especially under extreme operating conditions.
Now, a research team led by Professor Changzheng Hu from the College of Materials Science and Engineering at Guilin University of Technology has developed a new class of lead-free relaxor ferroelectric ceramics that overcome these limitations. By integrating high-entropy design with bandgap engineering, the researchers synthesized a series of tungsten bronze-structured ceramics with the composition Ba2.38Sr2.12Sm0.5Gd0.5Ti1Zr1Nb8-xTaxO30.
The high-entropy approach introduces multiple cations into the crystal lattice, creating significant atomic-scale disorder. This disrupts long-range ferroelectric order and promotes the formation of polar nanoregions (PNRs), which reduce energy loss and enhance polarization reversal. Simultaneously, the incorporation of tantalum (Ta) widens the material's bandgap, increasing its resistance to electrical breakdown.
The team published their work in Journal of Advanced Ceramics on February 8, 2026.
"The synergy between high-entropy effects and bandgap engineering allows us to finely tune the microstructure and electronic properties," said Professor Hu. "We observed grain refinement, increased resistivity, and a broader bandgap—all of which contribute to a significantly enhanced breakdown electric field."
The results are striking: the Ta-0.5 composition achieved a recoverable energy density of 7.93 J·cm-3 and an energy efficiency of 94.25% at an electric field of 830 kV·cm-1. Under over-damped discharge conditions, the ceramic delivered an ultrafast discharge time of just 1.56 µs, with a discharge energy density of 5.20 J·cm-3. In under-damped mode, it reached a current density of 971.34 A·cm-2 and a power density of 155.41 MW·cm-3.
Moreover, the material demonstrated exceptional thermal stability: its discharge energy density varied by less than 10% across a temperature range of 30 °C to 180 °C, highlighting its suitability for harsh environments.
"Our work demonstrates that high-entropy tungsten bronze ceramics, when combined with bandgap engineering, offer a powerful and versatile platform for next-generation energy storage applications," added Professor Hu. "This strategy opens new avenues for developing high-performance dielectric materials for pulsed power systems, electric vehicles, and aerospace technologies."
About Author
Changzheng Hu is a professor at the College of Materials Science and Engineering, Guilin University of Technology, China. His research focuses on the ferroelectric, dielectric, and catalytic properties of tungsten bronze-structured ceramics. He has served as principal investigator for two projects funded by the National Natural Science Foundation of China and three projects supported by the Guangxi Natural Science Foundation. He has received two Second-Class Prizes for Natural Science from the Guangxi Zhuang Autonomous Region. Professor Hu has published over 40 SCI-indexed papers as first author or corresponding author in prestigious journals such as Nano Energy, Journal of Advanced Ceramics, and Materials Today Chemistry. He has also authored one academic monograph and holds more than ten authorized Chinese invention patents.
Funding
This work was supported by the National Natural Science Foundation of China (12164012), Guangxi Science and Technology Program (AA25069001, AD25069100)
About Journal of Advanced Ceramics
Journal of Advanced Ceramics (JAC) is an international academic journal that presents the state-of-the-art results of theoretical and experimental studies on the processing, structure, and properties of advanced ceramics and ceramic-based composites. JAC is Fully Open Access, monthly published by Tsinghua University Press, and exclusively available via SciOpen . JAC's 2024 IF is 16.6, ranking in Top 1 (1/34, Q1) among all journals in "Materials Science, Ceramics" category, and its 2024 CiteScore is 25.9 (5/130) in Scopus database. ResearchGate homepage: https://www.researchgate.net/journal/Journal-of-Advanced-Ceramics-2227-8508
