Publication近日，廣東以色列理工學院材料科學與工程系譚啟教授（共同通訊作者）與四川大學合作在國際頂級期刊《自然-通訊》上發表題為“Excellent Hardening Effect in Lead-Free Piezoceramics by Embedding Local Cu-doped Defect Dipoles in Phase Boundary Engineering”的高水平論文，采用新策略實現無鉛壓電陶瓷的優異硬化效果，有望推動其在高功率應用中的發展。該研究獲MATEC重點實驗室開放研究項目資助，彰顯了廣以學者在國際材料研究領域的前沿地位。《自然-通訊》是國際頂尖學術期刊《自然》旗下的子刊，也是材料化學等領域公認的高水平期刊，以嚴格的同行評審和學術影響力著稱。該期刊在JCR分區中常年位列Q1， 2024年影響因子為14.7。研究背景與問題壓電陶瓷是一種特殊的陶瓷材料，它可以實現機械能與電能的相互轉換，在工業和科技領域有著廣泛應用，包括聲波傳感器、聲波發生器、電子點火器、壓力傳感器等。傳統含鉛壓電陶瓷（如PZT）因性能優異且大規模工業化生產，在市場中占據主導地位。然而，鉛的毒性對環境有害，因此開發無鉛壓電陶瓷以替代含鉛材料成為研究的重要趨勢。其中，基于鉀鈉鈮酸鹽（KNN）的無鉛壓電陶瓷因其在相界工程、織構化、缺陷工程和復合陶瓷等方面取得的顯著進展而備受關注，展現出較高的壓電系數（d??）、電致應變和溫度穩定性。
譚啟教授發表、聯合發表超過120篇期刊文章、2本大學教材、3本書籍章節及50份企業內部報告。作為一個創新者，他在陶瓷、聚合物、儲能和電子器件領域擁有60項專利及商業秘密。作為企業及美國政府科技項目的首席科學家，率先開發了納米絕緣介電復合材料、高溫高能量密度電容器。譚啟教授獲得多個獎項，包括中國科學院自然科學獎一等獎，通用電氣全球研究中心創新獎，2022年廣東以色列理工學院最佳教學獎，2023年中國創新創業成果交易會最具投資價值科技成果獎等獎項。他同時還是MRS, ACERS, SPIE, iMAPS and IEEE等學術機構的成員及多家期刊的評審人。
PublicationRecently, Professor Daniel Q. Tan from the Department of Materials Science and Engineering at Guangdong Technion-Israel Institute of Technology (GTIIT) co-published a high-impact paper as a corresponding author in the top journal Nature Communications by collaborating with Sichuan University. The study, titled "Excellent Hardening Effect in Lead-Free Piezoceramics by Embedding Local Cu-doped Defect Dipoles in Phase Boundary Engineering," proposed a new strategy to achieve excellent hardening effect in lead-free piezoceramics, paving the way for their application in high-power devices. The study was supported by the MATEC open research program, reinforcing GTIIT scholars’ leading role in international materials research.Nature Communications is a sub-journal of the renowned and international journal Nature, widely recognized as a high-impact publication in fields such as materials science and chemistry. Known for its rigorous peer-review process and strong academic influence, it consistently ranks in the JCR Q1 category, with a 2024 impact factor of 14.7.Research backgroundPiezoelectric ceramics are a type of ceramic materials capable of interconverting mechanical and electrical energy, with extensive industrial applications such as ultrasonic transducers, acoustic generators, electronic igniters, and pressure sensors. Piezoceramics, represented by lead zirconate titanate (Pb(Zr, Ti)O?, PZT) family, dominate the piezoelectric market due to excellent electrical properties and large-scale industrial production. Considering the toxicity of lead (Pb) and the need for environmental protection, research on lead-free piezoceramics to replace Pb-based ones is imperative. Among these, potassium sodium niobate ((K, Na)NbO?, KNN)-based lead-free piezoceramics stand out due to the significant progress in their piezoelectric coefficient (d??), electro-strain, and temperature stability achieved through phase boundary engineering (PBE), texturing, defect engineering, and composite ceramics.
To make KNN achieve the?industrial-scale production of high-power applications, piezoceramics are expected to have both high d?? and mechanical quality factor (Q?) (also known as hard piezoceramics) as they operate in resonant mode. High d?? ensures the good electromechanical properties, while high Q? reduces the heat generation caused by dissipated energy. However, achieving a balance between d?? and Q? is highly challenging because they have different preferences for extrinsic contributions. This imbalance is more pronounced in KNN-based piezoceramics. Traditional acceptor doping (i.e., copper Cu and manganese Mn) and the newly-proposed isolatedoxygen-vacancy strategy greatly improve Q? but fail to ensure high d??, which compromises the mechanical properties, rendering mass production unfeasible. Additionally, traditional acceptor doping is mainly implemented on pristine KNN ceramics with low d?? values (e.g., <150 pC/N), resulting in even worse d?? after acceptor doping as expected.
Solutions and resultsThis study proposed a new strategy to study potassium sodium niobate (KNN)-based lead-free piezoelectric ceramics and achieved important results in many aspects. By embedding local copper acceptor defect dipoles in orthogonal-tetragonal phase boundary engineering (O-T PBE), the d?? and Q? balance of KNN-based ceramics was achieved. This strategy retains the room temperature O-T phase boundary and introduces dimer (CuNb′′′-Vo??)' and trimer (Vo??-CuNb′′′-Vo??)? defects. The existence of trimer defects was confirmed by X-ray absorption fine structure (XAFS) spectroscopy and first-principles calculations. The retained O-T phase boundary and the local structural inhomogeneity caused by the defects ensure high d33, and the defect dipoles formed by the dimer defects polarize the PD pinning domain wall motion and improve Q?. The KNN-BNH-1Cu sample was made better than other typical KNN-based piezoelectric ceramics.
Mesoscopic ferroelectric domain structure?
and polarization hysteresis behavior
Electromechanical properties?
and domain evolution model
?
ConclusionBased on O-T PBE, by introducing copper acceptor doping, dimer (????????′′′???????)′ and trimer (???????????????′′′???????)? defects are formed. Dimer defects form defect dipole polarization and pin domain wall motion; trimer defects introduce local structural heterogeneity, resulting in nanoscale multiphase coexistence and rich nanodomains. Experimental results show that when the copper doping amount x=1, Q? increases by 4 times, while d?? only decreases by 1/5 (reaching 340 pC/N, Q? is 256). This strategy provides a new paradigm for the balance between d?? and Q? in lead-free piezoelectric ceramics, which is expected to promote their development in high-power applications and promote the practical application of lead-free piezoelectric ceramics in more fields.Paper linkhttps://www.nature.com/articles/s41467-025-58269-5PROFILE譚啟(Daniel Tan)Professor and Deputy Head
of Materials Science
and Engineering Program
Daniel Tan was recruited and appointed by Technion - Israel Institute of Technology as the professor of Guangdong Technion - Israel Institute of Technology in August 2018. Dr. Tan received a Ph. D. in Materials Science and Engineering from University of Illinois at Urbana-Champaign (UIUC) in 1998, and a Ph.D in Solid State Physics from Chinese Academy of Science in 1989 following Academician T.S.Ke. He used to?teach?at the University of Science and Technology of China. In 1994, he moved to the United States as a visiting scientist (Argonne National Laboratory and UIUC). He joined Honeywell Corp. in 1998 as a Sr. Scientist to develop high-K ferroelectric materials for semiconductor industry. In 2000, he was recruited to CTS Corp. as a Sr. Staff Engineer to develop high performance piezoelectric transducers and cell phone antenna materials. In the following 12 years, he dedicated his passion, innovation and pioneering efforts in Nanodielectrics and Energy Storage to General Electric. In 2016, he joined W.L. Gore as a Sr. Polymer Dielectric Scientist to further the high performance polymer investigations for capacitor and membrane technology.
Dr. Tan has authored/co-authored over 120 journal papers, 2 college teaching textbooks, 3 book chapters, and 50 corporate internal reports. As an innovator, he holds 60 patents and trade secrets in the field of ceramics, polymers, energy storage and electronic components. He has pioneered development in nanodielectric composites, high temperature and high energy density capacitors as a principal scientist for industry and US government. He is the recipient of various awards including the First Place Prize of Natural Science Award of Chinese Academy of Science, GE Global Research Innovation Award, 2022 Best Teaching Award of Guangdong Technion - Israel Institute of Technology, and The Most Worthy Technology Investment Award from the China Innovation and Entrepreneurship Fair 2023. He is a member of MRS, ACERS, SPIE, iMAPS and IEEE and reviewers of several journals.
