[1] [1] YANG L T, KONG X, LI F, et al. Perovskite lead-free dielectrics for energy storage applications[J]. Prog Mater Sci, 2019, 102: 72-108.

[2] [2] ZHANG L, PU Y P, CHEN M, et al. Design strategies of perovskite energy-storage dielectrics for next-generation capacitors[J]. J Eur Ceram Soc, 2023, 43(14): 5713-5747.

[3] [3] YANG Minzheng, JIANG Jianyong, SHEN Yang. J Chin Ceram Soc, 2021, 49(7): 1249-1262.

[4] [4] YANG Z T, DU H L, JIN L, et al. High-performance lead-free bulk ceramics for electrical energy storage applications: Design strategies and challenges[J]. J Mater Chem A, 2021, 9(34): 18026-18085.

[5] [5] HE Q F, SUN K, SHI Z C, et al. Polymer dielectrics for capacitive energy storage: From theories, materials to industrial capacitors[J]. Mater Today, 2023, 68: 298-333.

[6] [6] CHE Z Y, MA L, LUO G G, et al. Phase structure and defect engineering in (Bi0.5Na0.5)TiO3-based relaxor antiferroelectrics toward excellent energy storage performance[J]. Nano Energy, 2022, 100: 107484.

[7] [7] DU Jinhua, LI Yong, SUN Ningning, et al. J Chin Ceram Soc, 2022, 50(3): 608-624.

[8] [8] YANG D, GAO J, SHU L, et al. Lead-free antiferroelectric niobates AgNbO3 and NaNbO3 for energy storage applications[J]. J Mater Chem A, 2020, 8(45): 23724-23737.

[9] [9] WANG Zixuan, LI Zhuo, ZHANG Jiayong, et al. J Chin Ceram Soc, 2023, 51(6): 1530-1540.

[10] [10] CHEN J, FENG D. TEM study of phases and domains in NaNbO3 at room temperature[J]. Phys Status Solidi A, 1988, 109(1): 171-185.

[11] [11] XU Y H, HONG W, FENG Y J, et al. Antiferroelectricity induced by electric field in NaNbO3-based lead-free ceramics[J]. Appl Phys Lett, 2014, 104(5): 052903.

[12] [12] ZHANG M H, ZHAO C H, FULANOVI? L, et al. Revealing the mechanism of electric-field-induced phase transition in antiferroelectric NaNbO3 by in situ high-energy X-ray diffraction[J]. Appl Phys Lett, 2021, 118(13): 132903.

[13] [13] QI H, ZUO R Z. Evolving antiferroelectric stability and phase transition behavior in NaNbO3-BaZrO3-CaZrO3 lead-free ceramics[J]. J Eur Ceram Soc, 2019, 39(7): 2318-2324.

[14] [14] SHIMIZU H, GUO H Z, REYES-LILLO S E, et al. Lead-free antiferroelectric: xCaZrO3-(1-x)NaNbO3 system (0≤x≤0.10)[J]. Dalton Trans, 2015, 44(23): 10763-10772.

[15] [15] LIU Z Y, LU J S, MAO Y Q, et al. Energy storage properties of NaNbO3-CaZrO3 ceramics with coexistence of ferroelectric and antiferroelectric phases[J]. J Eur Ceram Soc, 2018, 38(15): 4939-4945.

[16] [16] CHEN Z G, MAO S F, MA L, et al. Phase engineering in NaNbO3 antiferroelectrics for high energy storage density[J]. J Materiomics, 2022, 8(4): 753-762.

[17] [17] LUO N N, HAN K, CABRAL M J, et al. Constructing phase boundary in AgNbO3 antiferroelectrics: Pathway simultaneously achieving high energy density and efficiency[J]. Nat Commun, 2020, 11(1): 4824.

[18] [18] ZHOU Mingxing. Study on preparation, structure and properties of sodium niobate-based lead-free ferroelectric ceramics[D]. Beijing: University of Chinese Academy of Sciences, 2020.

[19] [19] QI He. Study on dielectric relaxation regulation, electromechanical properties and structural mechanism of sodium niobate-based lead-free piezoelectric ceramics[D]. Hefei: Hefei University of Technology, 2017.

[20] [20] FU J, ZUO R Z, WANG X H, et al. Phase transition characteristics and piezoelectric properties of compositionally optimized alkaline niobate based ceramics[J]. J Alloys Compd, 2009, 486(1/2): 790-794.

[21] [21] GUO H Z, SHIMIZU H, MIZUNO Y, et al. Strategy for stabilization of the antiferroelectric phase (Pbma) over the metastable ferroelectric phase (P21ma) to establish double loop hysteresis in lead-free (1-x)NaNbO3-xSrZrO3 solid solution[J]. J Appl Phys, 2015, 117(21): 214103.

[22] [22] GAO L S, GUO H Z, ZHANG S J, et al. A perovskite lead-free antiferroelectric xCaHfO3-(1-x)NaNbO3 with induced double hysteresis loops at room temperature[J]. J Appl Phys, 2016, 120(20): 204102.

[23] [23] GAO L S, GUO H Z, ZHANG S J, et al. Stabilized antiferroelectricity in xBiScO3-(1-x)NaNbO3 lead-free ceramics with established double hysteresis loops[J]. Appl Phys Lett, 2018, 112(9): 092905.

[24] [24] YE J M, WANG G S, CHEN X F, et al. Effect of rare-earth doping on the dielectric property and polarization behavior of antiferroelectric sodium niobate-based ceramics[J]. J Materiomics, 2021, 7(2): 339-346.

[25] [25] ZHOU H Y, LIU X Q, ZHU X L, et al. CaTiO3 linear dielectric ceramics with greatly enhanced dielectric strength and energy storage density[J]. J Am Ceram Soc, 2018, 101(5): 1999-2008.

[26] [26] NIKOLI? J, PAVI? L, ?ANTI? A, et al. Novel insights into electrical transport mechanism in ionic-polaronic glasses[J]. J Am Ceram Soc, 2018, 101(3): 1221-1235.

[27] [27] KIM C, PILANIA G, RAMPRASAD R. From organized high- throughput data to phenomenological theory using machine learning: the example of dielectric breakdown[J]. Chem Mater, 2016, 28(5): 1304-1311.

[28] [28] TRIPATHI S, PANDEY D, MISHRA S K, et al. Morphotropic phase-boundary-like characteristic in a lead-free and non-ferroelectric (1-x)NaNbO3-xCaTiO3 system[J]. Phys Rev B, 2008, 77(5): 052104.

[29] [29] SHI R K, PU Y P, WANG W, et al. A novel lead-free NaNbO3- Bi(Zn0.5Ti0.5)O3 ceramics system for energy storage application with excellent stability[J]. J Alloys Compd, 2020, 815: 152356.

[30] [30] HUSSAIN A, NAWAZ S, JABEEN N, et al. Enhanced ferroelectric and piezoelectric response by MnO2 added Bi0.5(K0.2Na0.8)0.5TiO3 ceramics[J]. J Solid State Chem, 2022, 306: 122716.

[31] [31] LI Mingyang, CAO Jianing, WANG Mengkai, et al. J Huanghe S&T Coll, 2022, 24(11): 26-29.

[32] [32] LUO G G, ZHUANG D Y, YANG K H, et al. Enhanced comprehensive energy storage properties in NaNbO3-based relaxor antiferroelectric via MnO2 modification[J]. J Mater Sci Mater Electron, 2023, 34(18): 1444.

[33] [33] LI X H, JIANG M, LIU J, et al. Phase transitions and electrical properties of (1?x)(K0.5Na0.5)NbO3?xBiScO3 lead-free piezoelectric ceramics with a CuO sintering aid[J]. Phys Status Solidi A, 2009, 206(11): 2622-2626.

[34] [34] JAIN A, WANG Y G, WANG N, et al. Critical role of CuO doping on energy storage performance and electromechanical properties of Ba0.8Sr0.1Ca0.1Ti0.9Zr0.1O3 ceramics[J]. Ceram Int, 2020, 46(11): 18800-18812.

[35] [35] DOU M X, FU J, ZUO R Z. Electric field induced phase transition and accompanying giant poling strain in lead-free NaNbO3-BaZrO3 ceramics[J]. J Eur Ceram Soc, 2018, 38(9): 3104-3110.

[36] [36] QI H, XIE A W, FU J, et al. Emerging antiferroelectric phases with fascinating dielectric, polarization and strain response in NaNbO3-(Bi0.5Na0.5)TiO3 lead-free binary system[J]. Acta Mater, 2021, 208: 116710.

[37] [37] XIE A W, FU J, ZUO R Z, et al. NaNbO3-CaTiO3 lead-free relaxor antiferroelectric ceramics featuring giant energy density, high energy efficiency and power density[J]. Chem Eng J, 2022, 429: 132534.

[38] [38] TRIPATHI S, MISHRA S K, KRISHNA P S R, et al. Morphotropic phase transition in a lead-free system (1-x)NaNbO3-xCaTiO3[J]. Acta Cryst Sect A, 2011, 67(a1): C672.

[39] [39] SHAKHOVOY R A, RAEVSKAYA S I, SHAKHOVAYA L A, et al. Ferroelectric Q and antiferroelectric P phases’ coexistence and local phase transitions in oxygen-deficient NaNbO3 single crystal: Micro-Raman, dielectric and dilatometric studies[J]. J Raman Spectrosc, 2012, 43(8): 1141-1145.

[40] [40] GE G L, SHI C, CHEN C K, et al. Tunable domain switching features of incommensurate antiferroelectric ceramics realizing excellent energy storage properties[J]. Adv Mater, 2022, 34(24): 2201333.

[41] [41] WANG X J, WANG X Z, HUAN Y, et al. A combined optimization strategy for improvement of comprehensive energy storage performance in sodium niobate-based antiferroelectric ceramics[J]. ACS Appl Mater Interfaces, 2022, 14(7): 9330-9339.

[42] [42] WEI K, DUAN J H, ZHOU X F, et al. Achieving ultrahigh energy storage performance for NaNbO3-based lead-free antiferroelectric ceramics via the coupling of the stable antiferroelectric R phase and nanodomain engineering[J]. ACS Appl Mater Interfaces, 2023, 15(41): 48354-48364.

[43] [43] HUANG Jiajia, ZHANG Yong, CHEN Jichun. Mater Rep, 2009, 23(Suppl 1): 307-312.

[44] [44] LIU W F, REN X B. Large piezoelectric effect in Pb-free ceramics[J]. Phys Rev Lett, 2009, 103(25): 257602.

[45] [45] LIU W B, ZHENG T, RUAN X Z, et al. Synergy of lead vacancies and morphotropic phase boundary to promote high piezoelectricity and temperature stability of PBZTN ceramics[J]. J Mater Sci Technol, 2023, 137: 1-7.

[46] [46] XU R, XU Z, FENG Y J, et al. Evaluation of discharge energy density of antiferroelectric ceramics for pulse capacitors[J]. Appl Phys Lett, 2016, 109(3): 032903.