With the rapid development of the Internet of Things (IoT) and intelligent sensing technologies, high-sensitivity sensing materials have become critical for next-generation electronic systems. However, conventional piezoelectric ceramics face a long-standing challenge: the strong intrinsic coupling between the piezoelectric charge coefficient (d₃₃) and the dielectric constant (εᵣ). Although various strategies can enhance d₃₃, they are typically accompanied by a simultaneous increase in εᵣ, thereby limiting improvements in the piezoelectric voltage coefficient (g₃₃) and overall sensing sensitivity. This fundamental trade-off has significantly constrained the application of piezoelectric materials in weak-signal detection, wearable electronics, and self-powered systems.
To address this issue, a research team from Northwestern Polytechnical University and collaborators has proposed a novel structural design strategy: three-dimensionally interconnected porous piezoceramics (3D-PPCs). Using an innovative foam-gelcasting approach, the team successfully fabricated PZT-PZN-PNN-based porous ceramics with fully open-cell, three-dimensional interconnected architectures.
The key to this method lies in the precise control of slurry rheology and foam stability. By introducing surfactants to modify particle wettability, ceramic particles self-assemble at the gas–liquid interface to form stable foams. Meanwhile, a temperature-responsive gelatin network is employed to solidify the structure, enabling the retention of complex three-dimensional architectures. During sintering, this framework evolves into a highly interconnected ceramic skeleton, while suppressing abnormal grain growth and promoting the formation of multiscale domain structures.
"We are not simply reducing the dielectric constant by introducing porosity," said the project leader. "Instead, we use the three-dimensional interconnected architecture to actively regulate local stress and electric field distributions, fundamentally altering the electromechanical coupling mechanism. This provides a new pathway to break the conventional performance trade-off."
The team published their work in Journal of Advanced Ceramics on March 11, 2026.
Experimental results demonstrate that the material maintains a high d₃₃ of approximately 470 pC/N even at an ultrahigh porosity of 92%, which is about 90% of that of dense ceramics. At the same time, the dielectric constant is significantly reduced to ~140 (a decrease of ~94%), resulting in an approximately 14-fold enhancement in g₃₃. Multiscale characterization and finite element simulations reveal that this performance originates from synergistic effects: stress concentration within the interconnected skeleton enhances load transfer, electric field distortion at air–ceramic interfaces promote polarization, and multiscale domain structures combined with reduced oxygen vacancy concentration improve domain wall mobility.
In terms of performance validation, the material exhibits outstanding sensing capability. Under low-frequency, weak mechanical excitation, it generates output voltages up to 200 V—an order-of-magnitude improvement over dense ceramics—and achieves a sensitivity of 38.7 V/kPa, about 18 times higher than the reference sample. Moreover, stable output is maintained over 5000 loading cycles, demonstrating good preliminary reliability.
Importantly, comparative analysis with other porous architectures (e.g., 3–0, 2–2, and 3–1 types) shows that the three-dimensional interconnected structure achieves a superior balance between stress transfer and polarization efficiency, overcoming performance degradation caused by phase discontinuity or mechanical clamping in conventional systems.
From an application perspective, this novel porous piezoceramic shows great promise in health monitoring, environmental sensing, precision positioning, and self-powered microelectromechanical systems (MEMS). Its high sensitivity and high output make it particularly suitable for detecting weak signals, such as human pulse monitoring or micro-vibration sensing in structures.
Overall, this work not only introduces a scalable strategy for designing three-dimensional porous architectures but also reveals the active role of structural engineering in tuning piezoelectric performance. It provides important insights for the development of next-generation high-performance piezoelectric sensing materials.
About Author
Jie Xu (corresponding author) is an Associate Professor at the School of Materials Science and Engineering, Northwestern Polytechnical University, where he also serves as Director of the Department of Materials Science and Engineering. He is a council member of the Testing Technology Division of the Chinese Ceramic Society and a member of the Youth Committee of the Special Ceramics Division. He serves as a Assistant Editorial Board Member for Journal of Advanced Ceramics, Journal of Materiomics, and Rare Metals. His research focuses on the preparation of advanced inorganic powders, colloidal processing of advanced ceramics, and porous functional ceramic materials.
Mupeng Zheng (corresponding author) is an Associate Professor at the School of Materials Science and Engineering, Beijing University of Technology. He received his Ph.D. from Beijing University of Technology in 2015, and his doctoral dissertation was selected for the First Excellent Doctoral Dissertation Award of the Chinese Materials Research Society. He has led more than ten research projects, including those funded by the National Natural Science Foundation of China, the Beijing Natural Science Foundation, and the China Postdoctoral Science Foundation. He has been recognized as an Outstanding Young Talent by the Beijing Natural Science Foundation and selected for several talent programs at Beijing University of Technology.
Feng Gao (corresponding author) is a Professor in the School of Materials Science and Engineering at Northwestern Polytechnical University (NPU) in China. He received degrees of B.E., M.E. and Ph.D. in Materials Science and Engineering from NPU in Xi'an from 1992 to 2002. Following postdoctoral work at Postdoctoral mobile station of Aerospace Science and Technology in NPU from 2003 to 2005, he worked in Pennsylvania State University of America as visiting scholar. He is currently Chief-scientist of QMUL-NPU Joint Research Institute of Advanced Materials and Structures (AMAS JRI). His main research interests are development of advanced functional ceramics and composite materials, particular those intended for energy, microwave tunable and communication devices.
Shujun Zhang (corresponding author) is Chair Professor of Ceramics in the Department of Chemistry at City University of Hong Kong. He received his B.Sc. (1994) and Ph.D. (2000) in Solid State Chemistry from Shandong University. From 2000 to 2015, he held various academic and research positions in the Materials Research Institute and Department of Materials Science and Engineering at The Pennsylvania State University, USA. In 2015, he joined the University of Wollongong, Australia, as a professor and was later appointed Distinguished Professor. In 2025, he became Chair Professor of Ceramics in the Department of Chemistry at City University of Hong Kong. Prof. Zhang's research focuses on electronic materials, with particular emphasis on dielectric and ferroelectric materials for applications in transducers, sensors, electrocaloric, energy harvesting, and energy storage. He has been recognized as a Clarivate Highly Cited Researcher in either Cross-Field or Materials Science since 2021. He has received many awards and honours, including election as an Academician of the World Academy of Ceramics, IEEE Fellow, Fellow of the American Ceramic Society and ARC Future Fellowship.
Funding
This work has been supported by National Natural Science Foundation of China (No. 52472078, 52072301, 52272123), the Outstanding Scholar Foundation for Technology Innovation of Shaanxi Province (2024), National Key R&D Program of China (No. 2022YFB3504901) and the '111' Project (No. B20028).
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
