[1] [1] YAN Xiaodong,ZHENG Mupeng,HOU Yudong,et al.Composition-driven phase boundary and its energy harvesting performance of BCZT lead-free piezoelectric ceramic［J］.J Eur Ceram Soc,2017,37(7):2583-2589.

[2] [2] TSUJI K,FAN Zhongming,BANG S H,et al.Cold sintering of the ceramic potassium sodium niobate,(K0.5Na0.5)NbO3,and influences on piezoelectric properties［J］.J Eur Ceram Soc,2022,42(1):105-111.

[3] [3] MATTHIAS B T,REMEIKA J P.Dielectric properties of sodium and potassium niobates［J］.Physical Review,1951,82(5):727-729.

[5] [5] ZHANG Yang,SHEN Bo,ZHAI Jiwei,et al.New insight on sintering progress of KNN-based lead-free ceramics［J］.J Am Ceram Soc,2016,99(3):752-755.

[6] [6] KIM J H,KIM J S,HAN S H,et al.Low-temperature sintering and piezoelectric properties of CuO-doped (K,Na)NbO3 ceramics［J］.Mater Res Bull,2017,96(2):121-125.

[7] [7] LI Jingfeng,WANG Ke,ZHU Fangyuan,et al.(K,Na)NbO3-based lead-free piezoceramics:fundamental aspects,processing technologies,and remaining challenges［J］.J Am Ceram Soc,2013,96(12):3677-3696.

[8] [8] LIU Baihui,LI Peng,SHEN Bo,et al.Enhanced piezoelectric properties and temperature-insensitive strain behavior of -textured KNN-based ceramics［J］.Ceram Int,2017,43(11):8004-8009.

[9] [9] WU Jiagang,XIAO Dingquan,ZHU Jianguo. Potassium-sodium niobate lead-free piezoelectric materials:past,present,and future of phase boundaries［J］.Chem Rev,2015,115(7):2559-2595.

[10] [10] FENG Y,LI W L,XU D,et al.Defect engineering of lead-free piezoelectrics with high piezoelectric properties and temperature-stability［J］.ACS Appl Mater Inter,2016,8(14):9231-9241.

[11] [11] LV Xiang,ZHANG Xixiang,WU Jiagang.Nano-domains in lead-free piezoceramics:a review［J］.J Mater Chem A,2020,8(20):10026-10073.

[12] [12] YANG Zetian,GAO Feng,DU Hongliang,et al.Grain size engineered lead-free ceramics with both large energy storage density and ultrahigh mechanical properties［J］.Nano Energy,2019,58(1): 768-777.

[13] [13] TAO H,WU H,LIU Y,et al.Ultrahigh performance in lead-free piezoceramics utilizing a relaxor slush polar state with multiphase coexistence［J］.J Am Chem Soc,2019,141(35):13987-13994.

[14] [14] YAO Weizeng,ZHANG Jialiang,ZHOU Chunming,et al.Giant piezoelectricity,rhombohedral-orthorhombic-tetragonal phase coexistence and domain configurations of (K,Na)(Nb,Sb)O3-BiFeO3-(Bi,Na)ZrO3 ceramics［J］.J Eur Ceram Soc,2020,40(4):1223-1231.

[15] [15] CHEN Kui,MA Jian,SHI Caiyun,et al.Enhanced temperature stability in high piezoelectric performance of (K,Na)NbO3-based lead-free ceramics trough co-doped antimony and tantalum［J］.J Alloys Compd,2021,852(1): 156865-156872.

[16] [16] WANG X,WU J,XIAO D,et al.Giant piezoelectricity in potassium-sodium niobate lead-free ceramics［J］.J Am Chem Soc,2014,136(7):2905-2910.

[17] [17] TAN Zhi,ZHU Jianguo,ZHANG Yuxing,et al.Effects of Mo2/3Bi1/3 doping on the phase structure,microstructure,and piezoelectric properties of KNNS-BNZ ceramics［J］.Ceram Int,2015,41(10):14610-14614.

[18] [18] WU Bo,MA Jian,WU Wenjuan,et al.Enhanced electrical properties,phase structure,and temperature-stable dielectric of (K0.48Na0.52)NbO3-Bi0.5Li0.5ZrO3 ceramics［J］.Ceram Int,2018,44(1):1172-1175.

[19] [19] LV X,LI J,MEN T L,et al.High-performance 0-3 type niobate-based lead-free piezoelectric composite ceramics with ZnO inclusions［J］.ACS Appl Mater Inter,2018,10(36):30566-30573.

[20] [20] LIU Qing,LI Jingfeng,ZHAO Lei,et al.Niobate-based lead-free piezoceramics:A diffused phase transition boundary leading to temperature-insensitive high piezoelectric voltage coefficients［J］.J Mater Chem C,2018,6(5):1116-1125.

[22] [22] LI P,CHEN X,WANG F,et al.Microscopic insight into electric fatigue resistance and thermally stable piezoelectric properties of (K,Na)NbO3-based ceramics［J］.ACS Appl Mater Inter,2018,10(34):28772-28779.

[23] [23] QUAN Y,REN W,NIU G,et al.Large piezoelectric strain with superior thermal stability and excellent fatigue resistance of lead-free potassium sodium niobate-based grain orientation-controlled ceramics［J］.ACS Appl Mater Inter,2018,10(12):10220-10226.

[24] [24] LI Yingwei,LIU Yixuan,CHSNER P E,et al.Temperature dependent fracture toughness of KNN-based lead-free piezoelectric ceramics［J］.Acta Mater,2019,174(1):369-378.

[25] [25] XING J,HUANG Y,XU Q,et al.Realizing high comprehensive energy storage and ultrahigh hardness in lead-free ceramics［J］.ACS Appl Mater Inter,2021,13(24):28472-28483.

[26] [26] TAN Zhi,XIE Shaoxiong,JIANG Laiming,et al.Oxygen octahedron tilting,electrical properties and mechanical behaviors in alkali niobate-based lead-free piezoelectric ceramics［J］.J Materiomics,2019,5(3):372-384.

[28] [28] WENG Chungming,TSAI Chengche,HONG Chengshong,et al.Effects of LiNbO3-doping on properties of (Na0.535K0.48)NbO3 piezoelectric ceramics with high electromechanical coupling coefficient for application in surface acoustic wave devices［J］.Ceram Int,2017,43(14):11324-11330.

[30] [30] KIM D H,LEE T G,CHO S H,et al.Piezoelectric properties of (Na1-xKx)NbO3-based lead-free piezoelectric ceramics and their application in knocking sensor［J］.J Am Ceram Soc,2017,100(12):5367-5373.

[31] [31] ZHENG Mupeng,HOU Yudong,YAN Xiaodong,et al.A highly dense structure boosts energy harvesting and cycling reliabilities of a high-performance lead-free energy harvester［J］.J Mater Chem C,2017,5(31):7862-7870.

[32] [32] LIN Jinfeng,CAO Yingbo,ZHU Kun,et al.Ultrahigh energy harvesting properties in temperature-insensitive eco-friendly high-performance KNN-based textured ceramics［J］.J Mater Chem A,2022,10(14):7978-7988.

[35] [35] HONG Changhyo,HAN Hyoungsu,LEE Jaeshin,et al.Ring-type rotary ultrasonic motor using lead-free ceramics［J］.J Senso Scien Techn,2015,24(4):228-231.

[36] [36] WU Lang,XIAO Dingquan,WU Jiagang,et al.Good temperature stability of K0.5Na0.5NbO3 based lead-free ceramics and their applications in buzzers［J］.J Eur Ceram Soc,2008,28(15):2963-2968.

[37] [37] KIM Insung,JOO Hyeonkyu,SONG Jaesung,et al.Piezoelectric properties of rosen type piezoelectric transformer using 0.01Pb(Ni1/3Nb2/3)O3-0.08Pb(Mn1/3Nb2/3)O3-0.91Pb(Zr0.505Ti0.495)O3 ceramics［J］.J Korean Phys Soc,2010,56(1/2):374-377.

[38] [38] GUO Mingsen,LAM K H,LIN D M,et al.A Rosen-type piezoelectric transformer employing lead-free K0.5Na0.5NbO3 ceramics［J］.J Mater Sci,2007,43(2):709-714.