[1] ZHENG T, WU J G, XIAO D Q, et al. Recent development in lead-free perovskite piezoelectric bulk materials［J］. Progress in Materials Science, 2018, 98: 552-624.
[2] SEKHAR M C, VEENA E, KUMAR N S, et al. A review on piezoelectricmaterialsand their applications［J］. Crystal Research and Technology, 2023, 58(2): 2200130.
[3] JAFFE B, ROTH R S, MARZULLO S. Piezoelectric properties of lead zirconate-lead titanate solid-solution ceramics［J］. Journal of Applied Physics, 1954, 25(6): 809-810.
[4] DAMJANOVIC D. Contributions to the piezoelectric effect in ferroelectric single crystals and ceramics［J］. Journal of the American Ceramic Society, 2005, 88(10): 2663-2676.
[5] HENNINGS D. Barium titanate based ceramic materials for dielectric use［J］. International Journal of High Technology Ceramics, 1987, 3(2): 91-111.
[6] BECHMANN R. Elastic, piezoelectric, and dielectric constants of polarized Barium titanate ceramics and some applications of the piezoelectric equations［J］. The Journal of the Acoustical Society of America, 1956, 28(3): 347-350.
[7] LIU Y C, CHANG Y F, LI F, et al. Exceptionally high piezoelectric coefficient and low strain hysteresis in grain-oriented (Ba,Ca)(Ti,Zr)O3 through integrating crystallographic texture and domain engineering［J］. ACS Applied Materials & Interfaces, 2017, 9(35): 29863-29871.
[8] YIN H M, XU W J, ZHOU H W, et al. Effects of phase composition and grain size on the piezoelectric properties of HfO2-doped barium titanate ceramics［J］. Journal of Materials Science, 2019, 54(19): 12392-12400.
[9] RAWAT S, AGARWAL S, SINGH K C. Lead-free (Ba0.88Ca0.12)(Ti0.94Sn0.06)O3 piezoceramics: a comprehensive analysis of the phase evolution and enhancement of electrical properties induced by high energy ball milling［J］. Materials Chemistry and Physics, 2022, 279: 125735.
[10] ZHANG Y M, YU Y G, ZHANG N, et al. Simultaneous realization of good piezoelectric and strain temperature stability via the synergic contribution from multilayer design and rare earth doping［J］. Advanced Functional Materials, 2023, 33(11): 2211439.
[11] LIU W F, REN X B. Large piezoelectric effect in Pb-free ceramics［J］. Physical Review Letters, 2009, 103(25): 257602.
[12] ZHAO C L, WU H J, LI F, et al. Practical high piezoelectricity in Barium titanate ceramics utilizing multiphase convergence with broad structural flexibility［J］. Journal of the American Chemical Society, 2018, 140(45): 15252-15260.
[13] WU J G. Perovskite lead-free piezoelectric ceramics［J］. Journal of Applied Physics, 2020, 127(19): 190901.
[14] BIJALWAN V, HUGHES H, POOLADVAND H, et al. The effect of sintering temperature on the microstructure and functional properties of BCZT-xCeO2 lead free ceramics［J］. Materials Research Bulletin, 2019, 114: 121-129.
[15] WANG X J, HUAN Y, ZHU Y X, et al. Defect engineering of BCZT-based piezoelectric ceramics with high piezoelectric properties［J］. Journal of Advanced Ceramics, 2022, 11(1): 184-195.
[16] KOU Q W, YANG B, SUN Y, et al. Tetragonal (Ba,Ca)(Zr,Ti)O3 textured ceramics with enhanced piezoelectric response and superior temperature stability［J］. Journal of Materiomics, 2022, 8(2): 366-374.
[17] JAIBAN P, THEETHUAN T, KHUMTRONG S, et al. The effects of donor (Nb5+) and acceptor (Cu2+, Zn2+, Mn2+, Mg2+) doping at B-site on crystal structure, microstructure, and electrical properties of (Ba0.85Ca0.15)Zr0.1Ti0.9O3 ceramics［J］. Journal of Alloys and Compounds, 2022, 899: 162909.
[18] ZHOU C, ZHANG Q W, CAI W, et al. Cooling rate-dependent microstructure and electrical properties of BCZT ceramics［J］. Materials Science in Semiconductor Processing, 2022, 150: 106950.
[19] HUANG Y L, ZHAO C L, WU B, et al. Grain size effects and structure origin in high-performance BaTiO3-based piezoceramics with large grains［J］. Journal of the European Ceramic Society, 2022, 42(6): 2764-2771.
[20] BIJALWAN V, TOFEL P, SPOTZ Z, et al. Processing of 0. 55(Ba0.9Ca0.1)TiO3-0. 45Ba(Sn0.2Ti0.8)O3 lead-free ceramics with high piezoelectricity［J］. Journal of the American Ceramic Society, 2020, 103(8): 4611-4624.
[21] GAIED A I, DAHRI A, PERRIN V, et al. Synergistic effects of Zn B-site substitution in lead-free Ba0.95Ca0.05Ti0.92Sn0.08O3 ferroelectric ceramics for enhancing piezoelectric properties in energy harvesting applications［J］. Journal of Alloys and Compounds, 2023, 958: 170419.
[22] LAISHRAM R, RAJPUT S, SINGH K C. Particle-size-induced high piezoelectricity in (Ba0.88Ca0.12)(Ti0.94Sn0.06)O3 piezoceramics prepared from nanopowders［J］. Journal of Alloys and Compounds, 2020, 812: 152128.
[23] HU X H, GAO J H, WANG Y, et al. Reversible domain-wall-motion-induced low-hysteretic piezoelectric response in ferroelectrics［J］. The Journal of Physical Chemistry C, 2019, 123(25): 15434-15440.
[24] WANG S F, LIU Q B, CAI E P, et al. Relaxor behavior and superior ferroelectricity of Y2O3-doped (Ba0.98Ca0.02)(Ti0.94Sn0.04Zr0.02)O3 lead-free ceramics［J］. Journal of Rare Earths, 2022, 40(6): 942-951.
[25] ZHAO T X, QIU J H, MA M G, et al. Electrical properties of Ba0.96Ca0.04Ti0.90Sn0.10O3 lead-free ceramics with the addition of nano-CeO2［J］. Journal of Nanoscience and Nanotechnology, 2019, 19(9): 5661-5666.
[26] BAEK J S, KOH J H. Distortion control of (1-x)Ba(Hf, Ti)O3-x(Ba,Ca)TiO3 piezoelectric ceramics to improved piezoelectric properties and related Curie temperature［J］. Journal of Alloys and Compounds, 2022, 898: 162811.
[27] WANG W, MA Y B, JING R Y, et al. Concentration-driving pinning effect in lead-free Mn-substituted BCZT ferroelectric ceramics［J］. Ceramics International, 2023, 49(20): 33324-33332.
[28] LIU C, MAO R Y, WU Q Y, et al. Modification of BCZT piezoelectric ceramics by modulating oxygen vacancies in different sintering atmospheres［J］. AIP Advances, 2023, 13(6): 065217.
[29] WANG X J, HUAN Y, JI S J, et al. Ultra-high piezoelectric performance by rational tuning of heterovalent-ion doping in lead-free piezoelectric ceramics［J］. Nano Energy, 2022, 101: 107580.
[30] LI C, BAEK J S, KOH J H. Ce and Y Co-doping effects for (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 lead-free ceramics［J］. Coatings, 2021, 11(10): 1248.
[31] TIAN Y S, MA M Y, LI S Y, et al. Piezoelectricity and thermophysical properties of Ba0.90Ca0.10Ti0.96Zr0.04O3 ceramics modified with amphoteric Nd3+ and Y3+ dopants［J］. Materials, 2023, 16(6): 2369.
[32] FU J, XIE A W, LI T Y, et al. Ultrahigh piezoelectricity in (Ba,Ca)(Ti,Sn)O3 lead-free compounds with enormous domain wall contribution［J］. Acta Materialia, 2022, 230: 117862.
[33] PENG S Q, ZENG F F, WANG Y Y, et al. Structure and electrical properties in Sb-doped Ba0.93Ca0.07Ti0.92Sn0.08O3 ceramics near the phase coexistence point［J］. Journal of Materials Science: Materials in Electronics, 2020, 31(19): 16235-16246.
[34] GUO F Y, CAI W, GAO R L, et al. Microstructure, enhanced relaxor-like behavior and electric properties of (Ba0.85Ca0.15)(Zr0.1-xHfxTi0.9)O3 ceramics［J］. Journal of Electronic Materials, 2019, 48(5): 3239-3247.
[35] CHEN K, MA J, WU J, et al. Large piezoelectric performance in zirconium doped Ba0.86Sr0.14TiO3 lead-free ceramics through utilizing multiphase coexistence［J］. Journal of Materials Science: Materials in Electronics, 2019, 30(20): 18336-18341.
[36] WANG D W, FAN Z M, RAO G H, et al. Ultrahigh piezoelectricity in lead-free piezoceramics by synergistic design［J］. Nano Energy, 2020, 76: 104944.
[37] SHI J K, LIU J Y, XIE S X, et al. Dopant tuned multi-functionality in Barium titanate based lead-free piezoceramics［J］. Journal of Alloys and Compounds, 2023, 942: 169092.
[38] ZHAO C L, WU B, THONG H C, et al. Improved temperature stability and high piezoelectricity in lead-free Barium titanate-based ceramics［J］. Journal of the European Ceramic Society, 2018, 38(16): 5411-5419.
[39] WU W J, MA J, WANG N N, et al. Electrical properties, strain stability and electrostrictive behavior in 0.5BaZr0.2Ti0.8O3-(0. 5-x)Ba0.7Ca0.3TiO3-xBa0.7Sr0.3TiO3 lead-free ceramics［J］. Journal of Alloys and Compounds, 2020, 814: 152240.
[40] CAI E P, LIU Q B, GU H Z. Optimization of the electrical properties on lead-free Barium titanate-based piezoelectric by combining grain growth with orthorhombic-tetragonal phase boundary［J］. Journal of Alloys and Compounds, 2023, 948: 169775.
[41] LV X, ZHU J G, XIAO D Q, et al. Emerging new phase boundary in potassium sodium-niobate based ceramics［J］. Chemical Society Reviews, 2020, 49(3): 671-707.
[42] TAO H, WU H J, LIU Y, et al. Ultrahigh performance in lead-free piezoceramics utilizing a relaxor slush polar state with multiphase coexistence［J］. Journal of the American Chemical Society, 2019, 141(35): 13987-13994.
[43] WU L J, ZHENG T, WU J G. Structural origin of excellent fatigue resistance in KNN-based ceramics with multiphase coexistence［J］. Journal of the European Ceramic Society, 2024, 44(1): 205-214.
[44] SAITO Y, TAKAO H, TANI T, et al. Lead-free piezoceramics［J］. Nature, 2004, 432(7013): 84-87.
[45] ZHANG N, ZHENG T, WU J G. Lead-free (K,Na)NbO3-based materials: preparation techniques and piezoelectricity［J］. ACS Omega, 2020, 5(7): 3099-3107.
[46] WANG X P, WU J G, XIAO D Q, et al. Giant piezoelectricity in potassium-sodium niobate lead-free ceramics［J］. Journal of the American Chemical Society, 2014, 136(7): 2905-2910.
[47] XU K, LI J, LV X, et al. Superior piezoelectric properties in potassium-sodium niobate lead-free ceramics［J］. Advanced Materials, 2016, 28(38): 8519-8523.
[48] WU J G. Advances in lead-free piezoelectric materials［M］. Singapore: Springer, 2018.
[49] QI X C, REN P R, TONG X Q. Effect of heterovalent-ion doping and oxygen-vacancy regulation on piezoelectric properties of KNN based lead-free ceramics［J］. Ceramics International, 2023, 49(22): 34795-34804.
[50] LIU Q, PAN E, DENG H, et al. Enhanced piezoelectricity and non-contact optical temperature sensing performance in Er3+ ion modified (K,Na)NbO3-based multifunctional ceramics
[51] LIU T, CHEN Y, ZHENG Z S, et al. The high nano-domain improves the piezoelectric properties of KNN lead-free piezo-ceramics［J］. Ceramics International, 2023, 49(15): 25035-25042.
[52] LI R C, ZENG Y S, SUN X X, et al. Multidimensional synergy-induced high piezoelectricity and reliability KNN piezoceramics for high-frequency ultrasonic transducers［J］. Science China Materials, 2023, 66(2): 686-695.
[53] CEN Z Y, CAO F Z, FENG M Y, et al. Simultaneously improving piezoelectric strain and temperature stability of KNN-based ceramics via defect design［J］. Journal of the European Ceramic Society, 2023, 43(3): 939-946.
[54] HUAN Y, WANG X J, YANG W Y, et al. Optimizing energy harvesting performance by tailoring ferroelectric/relaxor behavior in KNN-based piezoceramics［J］. Journal of Advanced Ceramics, 2022, 11(6): 935-944.
[55] JIA P W, ZHENG Z S, LI Y L, et al. The achieving enhanced piezoelectric performance of KNN-based ceramics: decisive role of multi-phase coexistence induced by lattice distortion［J］. Journal of Alloys and Compounds, 2023, 930: 167416.
[56] HE B, LIU W P, ZHOU B W, et al. Softening effect of trace Fe-substituted potassium-sodium niobate-based lead-free piezoceramics［J］. Journal of Alloys and Compounds, 2022, 909: 164718.
[57] CHEN K, MA J, SHI C Y, et al. Enhanced temperature stability in high piezoelectric performance of (K,Na)NbO3-based lead-free ceramics trough co-doped antimony and tantalum［J］. Journal of Alloys and Compounds, 2021, 852: 156865.
[58] XIE Y N, XING J, TAN Z, et al. High mechanical quality factor and piezoelectricity in potassium sodium niobate ceramics［J］. Ceramics International, 2022, 48(5): 6565-6573.
[59] XIE L X, CHEN H, XIE Y N, et al. The roles of Sn4+ in affecting performance of Potassium Sodium Niobate ceramics［J］. Journal of Alloys and Compounds, 2022, 899: 163290.
[60] SHI C Y, MA J, WU J, et al. Coexistence of excellent piezoelectric performance and high Curie temperature in KNN-based lead-free piezoelectric ceramics［J］. Journal of Alloys and Compounds, 2020, 846: 156245.
[61] QIAO L, LI G, TAO H, et al. Full characterization for material constants of a promising KNN-based lead-free piezoelectric ceramic［J］. Ceramics International, 2020, 46(5): 5641-5644.
[62] WU B, ZHAO L, MA J, et al. Insights into the correlation between ionic characteristics and microstructure and multiferroic properties in KNN-based ceramics with BiMO3 modification［J］. Journal of Alloys and Compounds, 2023, 966: 171568.
[63] SALMANOV S, KOBLAR M, KMET B, et al. Structure and electrical properties of cold-sintered strontium-doped potassium sodium niobate［J］. Journal of the European Ceramic Society, 2023, 43(16): 7516-7523.
[64] TRIPATHY D, CHAKROBORTY S, GADTYA A S, et al. Enhanced dielectric and electrical performance of phosphonic acid-modified tantalum (Ta)-doped potassium sodium niobate (KNaNbO3)-P(VDF-HFP) composites［J］. The European Physical Journal E, 2023, 46(3): 21.
[65] TAN L M, WANG X C, ZHU W J, et al. Excellent piezoelectric performance of KNNS-based lead-free piezoelectric ceramics through powder pretreatment by hydrothermal method［J］. Journal of Alloys and Compounds, 2021, 874: 159770.
[66] LV X, ZHANG N, MA Y C, et al. Coupling effects of the A-site ions on high-performance potassium sodium niobate ceramics［J］. Journal of Materials Science & Technology, 2022, 130: 198-207.
[67] ZHOU J S, WANG K, YAO F Z, et al. Multi-scale thermal stability of niobate-based lead-free piezoceramics with large piezoelectricity［J］. Journal of Materials Chemistry C, 2015, 3(34): 8780-8787.
[68] ZHANG M H, ZHANG Q H, YU T T, et al. Enhanced electric-field-induced strains in (K,Na)NbO3 piezoelectrics from heterogeneous structures［J］. Materials Today, 2021, 46: 44-53.
[69] LV X, WU J G, ZHANG X X. A new concept to enhance piezoelectricity and temperature stability in KNN ceramics［J］. Chemical Engineering Journal, 2020, 402: 126215.
[70] HUANG Y L, ZHAO C L, WU B, et al. Diffused and successive phase transitions of (K,Na)NbO3-based ceramics with high strain and temperature insensitivity［J］. Journal of the American Ceramic Society, 2019, 102(5): 2648-2657.
[71] YAO F Z, WANG K, JO W, et al. Diffused phase transition boosts thermal stability of high-performance lead-free piezoelectrics［J］. Advanced Functional Materials, 2016, 26(8): 1217-1224.
[72] HUO X T, WANG F C, ZHANG T H, et al. A dispersed polycrystalline phase boundary constructed in CaZrO3 modified KNN based ceramics with both excellent piezoelectric properties and thermal stability［J］. Ceramics International, 2023, 49(10): 15751-15760.
[73] ZHOU C M, ZHANG J L, YAO W Z, et al. Highly temperature-stable piezoelectric properties of 0. 96(K0.48Na0.52)(Nb0.96Sb0.04)O3-0. 03BaZrO3-0. 01(Bi0.50Na0.50)ZrO3 ceramic in common usage temperature range［J］. Scripta Materialia, 2019, 162: 86-89.
[74] YANG W W, LI P, LI F, et al. Enhanced piezoelectric performance and thermal stability of alkali niobate-based ceramics［J］. Ceramics International, 2019, 45(2): 2275-2280.
[75] LIU Q, ZHANG Y C, ZHAO L, et al. Simultaneous enhancement of piezoelectricity and temperature stability in (K,Na)NbO3-based lead-free piezoceramics by incorporating perovskite zirconates［J］. Journal of Materials Chemistry C, 2018, 6(39): 10618-10627.
[76] DONG Z H, ZHAO P Y, MA X, et al. Excellent strain properties in (K,Na)NbO3-based piezoceramics induced by lamination composite strategy［J］. Chemical Engineering Journal, 2023, 472: 144763.
[77] YI S L, ZHANG W K, GAO G P, et al. Structural design and properties of fine scale 2-2-2 PZT/epoxy piezoelectric composites for high frequency application［J］. Ceramics International, 2018, 44(9): 10940-10944.
[78] CHEN Z W, LI Z Y, LI J J, et al. 3D printing of ceramics: a review［J］. Journal of the European Ceramic Society, 2019, 39(4): 661-687.
[79] HE Z X, GONG X T, LIU C L, et al. Preparation and properties of (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 lead-free ceramics via vat photopolymerization［J］. Additive Manufacturing, 2022, 59: 103170.
[80] RENTERIA A, BALCORTA V H, MARQUEZ C, et al. Direct ink write multi-material printing of PDMS-BTO composites with MWCNT electrodes for flexible force sensors［J］. Flexible and Printed Electronics, 2022, 7(1): 015001.
[81] MARIANI M, BELTRAMI R, MIGLIORI E, et al. Additive manufacturing of lead-free KNN by binder jetting［J］. Journal of the European Ceramic Society, 2022, 42(13): 5598-5605.
[82] WEI X X, LIU Y H, ZHAO D J, et al. 3D printing of piezoelectric Barium titanate with high density from milled powders［J］. Journal of the European Ceramic Society, 2020, 40(15): 5423-5430.
[83] CHEN W C, WANG F F, YAN K, et al. Micro-stereolithography of KNN-based lead-free piezoceramics［J］. Ceramics International, 2019, 45(4): 4880-4885.
[84] SUFIIAROV V, KANTYUKOV A, POPOVICH A, et al. Structure and properties of barium titanate lead-free piezoceramic manufactured by binder jetting process［J］. Materials, 2021, 14(16): 4419.
[85] ZHANG D C, YANG Y D, RAO W F. Parameter optimization for printing Barium titanate piezoelectric ceramics through digital light processing［J］. Micromachines, 2023, 14(6): 1146.
[86] CIOMAGA C E, CURECHERIU L P, LUKACS V A, et al. Optimization of processing steps for superior functional properties of (Ba,Ca)(Zr,Ti)O3 ceramics［J］. Materials, 2022, 15(24): 8809.
[87] SHI S F, HASHIMOTO H, SEKINO T. Optimizing the piezoelectric properties of Ba0.85Ca0.15Zr0.10Ti0.90O3 lead-free ceramics via two-step sintering［J］. Ceramics International, 2023, 49(8): 12293-12300.
[88] LPEZ-BLANCO S, OCHOA D A, AMORN H, et al. Fine-grained high-performance Ba0.85Ca0.15 Zr0.1Ti0.9O3 piezoceramics obtained by current-controlled flash sintering of nanopowders［J］. Journal of the European Ceramic Society, 2023, 43(16): 7440-7445.
[89] BIJALWAN V, TOFEL P. Synthesis of high density sub-10 μm (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3-xCeO2 lead-free ceramics using a two-step sintering technique［J］. Journal of Asian Ceramic Societies, 2019, 7(4): 536-543.
[90] ORLIK K, LORGOUILLOUX Y, MARCHET P, et al. Influence of microwave sintering on electrical properties of BCTZ lead free piezoelectric ceramics［J］. Journal of the European Ceramic Society, 2020, 40(4): 1212-1216.
[91] YAO W Z, ZHANG J L, WANG X M, et al. High piezoelectric performance and domain configurations of (K0.45Na0.55)0.98Li0.02Nb0.76Ta0.18Sb0.06O3 lead-free ceramics prepared by two-step sintering［J］. Journal of the European Ceramic Society, 2019, 39(2/3): 287-294.
