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(K,Na)NbO_(3)-based lead-free piezoceramics:Phase transition,sintering and property enhancement

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Journal of Advanced Ceramics 2012年第1期1卷 24-37页

作者： Ke WANG jing-feng li State Key Laboratory of New Ceramic and Fine Processing Department of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Most widely used piezoelectric ceramics are based on Pb(Zr,Ti)O3(PZT)composition which has adverse environmental and health effects due to its high lead *** and safety concerns with respect to the utilization,recycling,and disposal of lead-based piezoelectric ceramics have induced a new surge in developing lead-free piezoelectric *** all the lead-free ceramics,(K,Na)NbO3(KNN)has drawn increasing attention because of its well-balanced piezoelectric properties and better environmental *** basis of the author’s work,this review summarizes the progress that has been made in recent years on development of KNN-based piezoelectric ceramics,including crystallographic structure and phase transition analysis,pressurized solid-state sintering as well as liquid-phase-assisted sintering process,and poling treatment for property *** in all,KNN is a promising lead-free system,but more research is still required both from academic and industrial interests.

关键词： electrical properties ferroelectric properties piezoelectric properties perovskites niobates lead-free

(K,Na)NbO_(3)-based lead-free ceramics with enhanced temperature-stable piezoelectricity and efficient red luminescence

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Journal of Advanced Ceramics 2023年第2期12卷 373-385页

作者： Qing liU Er PAN Fucai liU jing-feng li School of Optoelectronic Science and Engineering University of Electronic Science and Technology of ChinaChengdu 610054China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

There has been a surge of research interest in the promising lead-free potassium-sodium niobate(KNN)-based ceramics,applications of which could be significantly promoted by improving thermal stability of ***,endowing the KNN-based ceramics with photoluminescence property by rare-earth-ion doping can make them more completive lead-free counterparts in potential applications such as novel multifunctional sensing ***,a novel KNN-based ceramic material doped with Eu was elaborately designed to simultaneously obtain enhanced temperaturestable piezoelectricity and good luminescence *** the introduction of diffused phase transition and the modulation of unit cell distortion,a large piezoelectric strain coefficient(d^(*)_(33))with a small variation(590±59 pm/V)over a wide temperature range(from room temperature to 110℃)was *** optimal composition also exhibited a considerable piezoelectric coefficient(d_(33))with small fluctuation(330±33 pC/N)from 20 to 80℃.In addition to the enhanced temperature-stable piezoelectricity,the luminescence of these ceramics was slightly enhanced with the elevation of BaZrO_(3)(BZ)doping contents,which could be attributed to the increased compositional disorder and the decreased unit cell distortion of the matrix ***,an optical characteristic was more prominent at ultra-low *** work unprecedentedly provides a novel paradigm for the design of multifunctional KNN-based ceramics with enhanced temperature-stable piezoelectricity and good luminescence property,revealing the great potential of the rare-earth-element-doped KNN material for future applications in the novel multifunctional devices.

关键词： piezoelectric thermal stability rare-earth lead-free potassium-sodium niobate(KNN)

Evolutions of mechanical and thermal properties of TmNbO_(4)/Tm_(3)NbO_(7) composites as protective coating materials

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Journal of Advanced Ceramics 2024年第11期13卷 1771-1785页

作者： Jiankun Wang lin Chen Baihui li Hao Xu Xiang Jiang jing-feng li jing feng Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China Southwest United Graduate School Kunming 650092China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

High fracture toughness,low thermal conductivity,and thermal expansion coefficient(TEC)matching substrate are essential for thermal barrier coatings(TBCs)and abradable seal coatings(ASCs).In this work,TmNbO_(4)/Tm_(3)NbO_(7) composites are designed and synthesized to increase their fracture toughness(KIC)and thermal insulation *** with those of TmNbO_(4)(KIC=2.2±0.1 MPa·m^(1/2))and Tm3NbO7(KIC=1.7±0.2 MPa·m^(1/2)),the increments in fracture toughness are as high as 50.0%and 91.1%,*** highest toughness reaches 3.3±0.4 MPa·m1/2,which is attributed to the superior combination of grains between TmNbO4 and Tm3NbO7,as well as the simultaneous effects of microcracks and crack bridging and *** estimation of the effect of the interfacial thermal resistance on the thermal conductivity at low temperatures was achieved using the minimum interfacial thermal resistance model.A novel method is proposed to inhibit radiative heat transfer by utilizing oxides with glass-like thermal conductivity to suppress thermal ***,the TmNbO4/Tm3NbO7 composite maintains a low thermal conductivity(1.19–2.02 W·m^(−1)·K^(−1))at 1000°*** high TECs(10.4×10^(−6)–11.8×10^(−6)·K^(−1) at 1500°C)and excellent high-temperature stability ensure that the designed TmNbO_(4)/Tm_(3)NbO_(7) composites can be used at temperatures reaching 1500°***,simultaneous enhancement of fracture toughness and thermal insulation in TmNbO_(4)/Tm_(3)NbO_(7) composites is effective,and the revealed mechanisms are useful for various materials.

关键词： thermal barrier coatings(TBCs) toughening mechanisms composites thermal conductivity thermal expansion thermal radiation

Low-cost and environmentally benign selenides as promising thermoelectric materials

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Journal of Materiomics 2018年第4期4卷 304-320页

作者： Tian-Ran Wei Chao-feng Wu Fu li jing-feng li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China State Key Laboratory of High Performance Ceramics and Superfine Microstructure Shanghai Institute of CeramicsChinese Academy of ScienceShanghai200050China Shenzhen Key Laboratory of Advanced Thin Films and Applications College of Physics and EnergyShenzhen UniversityShenzhen518060China Advanced Materials Institute Graduate School at ShenzhenTsinghua UniversityShenzhen518055China

Developing high-efficiency materials with earth-abundant and low-toxicity elements has become a popular trend in the field of *** these compounds,oxides and sulfides,the lighter,cheaper and green analogies of tellurides,have been extensively investigated and summarized as well defined ***,the vast family of selenides with better electrical performance,lower thermal conductivity and higher thermoelectric efficiency have not been specially *** in this review,we present recent advances in binary and multinary selenide thermoelectric materials,covering traditional PbSe,liquid-like Cu_(2)Se,layered SnSe,diamond-like and disordered multinary *** features of selenides are discussed based on both environmental concerns and from the perspective of chemical bonding,transport properties and *** is put on the“compositionstructure-processing-performance”relationship,and some interesting issues are ***,challenges for thermoelectric selenides are discussed,and possible optimization strategies are also suggested.

关键词： Thermoelectric materials Selenides Transport properties

Bi2Te3-based applied thermoelectric materials:research advances and new challenges

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National Science Review 2020年第12期7卷 1856-1858页

作者： Jun Pei Bowen Cai Hua-Lu Zhuang jing-feng li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua University

Thermoelectric (TE) materials can directly exchange heat and electricity in the solid *** devices that do not contain moving parts or produce emissions have been commercialized as electronic coolers and temperature st...

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Room-temperature thermoelectric materials: Challenges and a new paradigm

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Journal of Materiomics 2022年第2期8卷 427-436页

作者： Zhijia Han jing-Wei li feng Jiang Jiating Xia Bo-Ping Zhang jing-feng li Weishu liu The Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing100083China Department of Materials Science and Engineering Southern University of Science and TechnologyShenzhen518055China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Shenzhen Engineering Research Center for Novel Electronic Information Materials and Devices Southern University of Science and TechnologyShenzhenGuangdong518055China

Room-temperature thermoelectric materials provide promising solutions for energy harvesting from the environment,and deliver a maintenance-free power supply for the internet-of-things(IoTs).The currently available Bi_(2)Te_(3) family discovered in the 1950s,still dominates industrial applications,however,it has serious disadvantages of brittleness and the resource shortage of tellurium(1×10^(-3) ppm in the earth's crust).The novel Mg_(3)Sb_(2) family has received increasing attention as a promising alternative for room-temperature thermoelectric *** this review,the development timeline and fabrication strategies of the Mg 3 Sb 2 family are ***,an insightful comparison between the crystal-linity and band structures of Mg_(3)Sb_(2) and Bi_(2)Te_(3) is *** outlook is presented to discuss challenges and new paradigms in designing room-temperature thermoelectric materials.

关键词： Thermoelectric materials Mg_(3)Sb_(2) Bi_(2)Te_(3) Chemical bond engineering

Delineating complex ferroelectric domain structures via second harmonic generation spectral imaging

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Journal of Materiomics 2023年第2期9卷 395-402页

作者： Wei li Yunpeng Ma Tianyi feng Ziwan Du Yixuan liu Sergei VKalinin jing-feng li Qian li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China Department of Materials Science and Engineering University of Tennessee KnoxvilleKnoxvilleTN37996USA

Understanding the mechanisms and spatial correlations of crystallographic symmetry breaking in ferroelectric materials is essential to tuning their functional *** optical second harmonic generation(SHG)has long been utilized in ferroelectric studies,its capability for probing complex polar materials has yet to be fully ***,we develop a SHG spectral imaging method implemented on a home-designed laser-scanning SHG microscope,and demonstrate its application for a model system of(K,Na)NbO3 single *** model fitting analysis produces comprehensive information about the polarization vector orientations and relative fractions of constituent domain variants as well as their thermal evolution across the polymorphic phase *** domains and phases are clearly delineated at different temperatures,suggesting the phase competitions in(K,Na)***,we show that unsupervised matrix decomposition analysis can quickly and faithfully reveal domain configurations without a priori knowledge about specific material *** SHG spectral imaging method can be readily extended to other ferroelectric materials with potentials to be further enhanced.

关键词： Second harmonic generation Ferroelectrics Domain structure Bayes linear unmixing

High thermoelectric figure of merit ZT>1 in SnS polycrystals

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Journal of Materiomics 2020年第1期6卷 77-85页

作者： Asfandiyar Bowen Cai li-Dong Zhao jing-feng li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China School of Materials Science and Engineering Beihang UniversityBeijing100191China

Eco-friendly tin sulfide(SnS)has attracted increasing attention in the thermoelectric community because of its elemental abundance and analogous crystal structure to SnSe as a new thermoelectric ***,so far no high dimensionless thermoelectric figure of merit ZT>1 was reported in SnS *** work found an effective strategy for enhancing the thermoelectric performance of ptype polycrystalline SnS by Ag doping and vacancy engineering,leading to three orders of magnitude increase in carrier concentration and optimized effective mass and carrier *** a result of the enhanced electrical conductivity,three times higher power factor ~3.85 μW/cm K^(2) at 877 K is realized in Sn_(0.995)Ag_(0.005)S ***,nanostructuring with Ag nano-precipitates were formed in the Agdoped SnS ***,with introducing Sn vacancies in the crystal structure of Sn_(0.995-vac)Ag_(0.005)S,the power factor further enhanced to~4.25 μW/cm K^(2).In addition to the low-frequency phonons scattering by Ag nano-precipitates,dislocations strengthens the scattering of mid-frequency phonon,leading to an ultralow lattice thermal conductivity <0.5 W/m K above 800 K and a record high ZT up to 1.1 at 877 K in Sn_(0.99)Ag_(0.005)S polycrystals.

关键词： Thermoelectric tin sulfide Spark plasma sintering Nanoprecipitation Dislocation

Components of Volatile Oil from Water-caltrop and Their Anti-tumor Effect in vitro

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Chemical Research in Chinese Universities 2009年第1期25卷 56-59页

作者： ZHAO Wen-jing NIU feng-lan li jing DONG Qing HUANG Zhan-you School of Public Health Jilin University Changchun 130021 P. R. China

The volatile oil was extracted from water caltrop by steam distillation; it was then analyzed by GC-MS to obtain 16 components, 8 of which were identified. Apocynin was the most abundant one, accounting for 81.41% of the total oil. The in vitro inhibitory effects of the volatile oil on SMMC-7721, MCF-7, Hela, HL-60 cells, and human peripheral blood mononuclear cells（PBMC） were investigated via the MTT method. The morphological changes of the tumor cells were observed and the apoptosis of HL-60 cells was detected by flow cytometry. The proliferation of the tumor cells could be significantly inhibited and the apoptosis of HL-60 cells could be induced by the volatile oil. The proliferation inhibition effect of the volatile oil on HL-60 tumor cells and the induction of the apoptosis of ilL-60 cells had dose-dependent feature.

关键词： Water caltrop Volatile oil Tumor Apoptosis