Superior Energy Storage Performance up to 200°C in a Self-organized Trirelaxor-antiferroelectric Nanocomposite

Superior Energy Storage Performance up to 200°C in a Self-organized Trirelaxor-antiferroelectric Nanocomposite | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Superior Energy Storage Performance up to 200°C in a Self-organized Trirelaxor-antiferroelectric Nanocomposite Jinghui Gao, Jingzhe Xu, Yongbin Liu, Dong Wang, Li He, Lisheng Zhong, and 6 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3926354/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Despite extensive efforts over the past decade in enhancing the energy storage properties of dielectric materials, a challenging issue has remained unsolved that a material with good room-temperature-performance usually degrades significantly at higher temperatures. This issue renders many otherwise promising dielectric energy storage materials unusable because significant temperature rise of the energy storage devices is inevitable during their service and some applications are in high temperature environment. The challenge at high temperatures arises from the physical inevitability of vanishing ferroelectric domains that lead to drop in polarization, and exponentially increased charge transport activity which leads to charge leakage and electrical breakdown. Here we report a material strategy to meet this challenge by designing a self-organized nanocomposite (1-x)(Ba,Sr)(Ti,Sn)O 3 -xBi 1.5 ZnNb 1.5 O 7 composed of nano-sized antiferroelectric particles embedded into a trirelaxor matrix through a nanoscale phase separation process. At the optimal composition of x=0.11, the antiferroelectric-trirelaxor nanocomposite ceramic exhibits an outstanding energy storage performance from room temperature (energy density=8.5 J/cm 3 , efficiency=94.8% and a high figure of merit of 167 J/cm 3 ) up to a high temperature of 200°C (energy density ~4.85 J/cm 3 , efficiency>90% and figure of merit of 49 J/cm 3 ), which outperforms existing Pb-free dielectric materials. High-resolution transmission electron microscopy (TEM) and synchrotron x-ray diffractometry reveal that the coherent nanometric antiferroelectric particles and the trirelaxor nanodomains sustain over a wide temperature range. In-situ piezoresponse force microscopy (PFM) observation and phase-field simulations show that the nearly hysteresis-free switching of trirelaxor nanodomains is responsible for enhanced polarization (and hence energy density) and low hysteretic loss. Resistivity shows a 2~3 order of magnitude increase in electrical resistivity accompanying significant increase in breakdown strength up to high temperatures. Thermally stimulated depolarization current (TSDC) measurements suggest that the suppression of charge transport or leakage up to high temperature stems from charge trapping effect at high-density nanointerfaces between antiferroelectric and trirelaxor phases. These favorable effects in the nano-composite are responsible for its high energy storage performance up to high temperatures. Our research may provide a generic approach to achieving advanced dielectrics with outstanding performance at high temperatures. Physical sciences/Materials science/Nanoscale materials/Nanoparticles Physical sciences/Energy science and technology/Energy storage/Supercapacitors energy storage relaxor ferroelectric high-temperature performance tricritical effect antiferroelectricity Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Electric energy storage underpins many modern technologies from electric vehicles to advanced pulse power sources. There is a strong demand for an electric energy storage solution that can store large amount of electric energy (i.e., high energy-density) and simultaneously allows for high charging/discharging rate (i.e., high power-density). However, high energy-density and high power-density usually do not go hand in hand. Electric energy storage using electrochemical batteries such as lithum-ion batteries and fuel-cell batteries stores the input electrical energy in the form of chemical energy and thus can achieve high energy density but at the expense of low charging/discharging rate, being limited by the slow electrochemical reaction. To circumvent the low charging/discharging rate issue of electrochemical batteries, there has been a revived interest in electric energy storage by using dielectric capacitors 1–3 , because such capacitors store the electric energy as it is, i.e., in the form of electric charges; thus in theory the charging/discharging rate is commensurate with the speed of light and the actual rate is limited only by the electrical impedance of the charging/discharging circuit. However, conventional dielectric capacitors can store merely 3-4 order of magnitude smaller amount of energy when compared with electrochemical batteries 4,5 . Thus to make dielectric capacitors a viable solution for high energy-density storage, a leap in its energy-density is required. Over the last decade thin film ceramic capacitors have been shown to significantly enhance the energy density of ceramic capacitors by 1-2 order of magnitude 1,6 owing mostly to their exceedingly high breakdown strength as compared with that of bulk ceramics. These encouraging results have provided new impetus for exploring the potentials of dielectric capacitors 7–10 . However, since existing thin film capacitors are composed of a single-layer film (nanometer in thickness) deposited on a bulk substrate (~1 mm in thickness), the averaged energy-density of the film+substrate system is reduced by 4-5 orders of magnitude despite the high energy density within the film 10 . This issue renders the existing thin film capacitors technologically unviable for energy storage at present. For this reason, there is increasing interest in high-performance dielectric bulk capacitors 3,11 because bulk capacitors and its derivative – multi-layer ceramic capacitors (MLCC) can be mass-produced with mature ceramics technology and advances in dielectric materials can be easily scalable to industrial lines. Bulk ceramic capacitors and MLCC are mostly based on relaxor ferroelectrics because their relaxor transition temperature can be easily tailered to occur around room temperature where a mediocre and broad permittivity peak (i.e., temperature-insensitive) is achieved together with low loss 9,12,13 . However, a major challenge for this type of materials is to maintain high energy-density and low loss up to sufficiently high ambient temperatures (e.g., 200℃), because energy storage devices usually experience self-heating due to the heat dissipation of the system and sometimes the devices need to work in high-temperature environment. This challenge arises from the inevitable vanishing of polar nano-regions (PNRs, which contribute to high polarization) and the occurrence of charge transport (which leads to high loss and low electrical breakdown strength) at high temperatures. Consequently these detrimental effects at high temperatures render low energy storage ability and low efficiency of ceramic capacitors at high temperatures. Despite significant efforts in recent years 14 , an effective strategy that can simultaneously maintain high-polarization state and reduce charge transport at high temperatures is lacking. In recent years, a special type of relaxor materials called trirelaxor has been found to demonstrate outstanding permittivity around their trirelaxor transition temperature as compared with the normal relaxors 15 . Being different from a relaxor which is characterized by a single type of PNRs, a trirelaxor is a mixture state of PNRs with different polar symmetries of tetragonal, orthorthombic, rhombohedral; it is reminiscent of a tricritical point (TCP) modified by relaxor-forming dopants. Compared with a normal relaxor, a trirelaxor exhibits much high permittivity around its trirelaxor transition temperature yet maintaining temperature-insensitivity like a common relaxor. Therefore, trirelaxor materials may become a promising solution to energy storage demand due to their higher permittivity as compared with normal relaxors. However, trirelaxors also suffer from similar thermal degradation issues with those of common relaxors due to leakage current and dielectric breakdown. Thus trirelaxor alone cannot guarantee high energy storage ability and high storage efficiency up to high temperatures. Here we propose a strategy to achieve simultaneously excellent room-temperature energy-storage ability and outstanding resistance against thermal degradation by forming a self-organized nanocomposite composed of trirelaxor (TRE) matrix and antiferroelectric (AFE) nanoscale phases. A TRE/AFE nanocomposite based on (1-x)(Ba,Sr)(Ti,Sn)O 3 -xBi 1.5 ZnNb 1.5 O 7 (BSTS-BZN) system (x=0~20%) shows not only excellent room-temperature energy storage performance (energy density U e =8.5 J/cm 3 , efficiency η=94.8%, figure of merit Q F =167 J/cm 3 ) but also strong resistance against performance deterioration at high temperature: the material exhibits superior high energy storage performance (U e =4.85 J/cm 3 and η=90.3%, Q F =49 J/cm 3 ) even at 200°C, which outperforms existing Pb-free dielectric materials. The material design strategy is illustrated in Fig.1. Suitable starting materials (oxides and carbonates) are selected so as to form to a mixture consisting of tricritical ferroelectric material (Ba,Sr)(Ti,Sn)O 3 composition and the AFE inducer (Bi 1.5 ZnNb 1.5 O 7 ) composition (in Fig. 1(a1)). By controlling the calcining and sintering conditions, the dissolved Bi 3+ , Zn 2+ and Nb 5+ ions undergo a nanoscale phase separation which leads to a self-organized nanocomposite composed of nano-sized AFE particles (BZN-rich) embedded into a TRE matrix BST (BZN-poor) shown in Fig. 1(a2)-(a3). The tricriticality of BST has been reported to flatten the energy barriers which overcome the energy loss and high energy barriers issues in conventional relaxor (in Fig. 1(b1)) and thus leading to high polarization response and high energy storage efficiency, and strong random fields by BZN changes the tri-critical ferroelectric matrix into a TRE matrix with highly stable TRE nanodomains that can persist to high temperatures (shown in Fig. 1(b2)). As the result, the BZN-doped TRE matrix can ensure high polarization response of the system up to high temperatures. On the other hand, the formation of coherent AFE nanoparticles introduces high-density nanointerfaces between AFE and TRE matrix, which act as deep traps to charge carriers (holes and electrons) and thus lead to low leakage and high breakdown strength at both room temperature and high temperatures. As the result, high energy storage efficiency (i.e., low loss) and high breakdown strength can be achieved up to high temperatures in our system when compared with conventional ferroelectrics and relaxors. 2. Results And Discussion 2.1. Energy storage performance from room temperature up to 200℃ To characterize the energy storage performance of BSTS- x BZN, the energy density, charging/discharging energy efficiency and figure of merit (Q F = U e /(1-η) reflects how good a capacitor can store electrical energy against lossy dissipation 1,1 1,13 ) are obtained by P - E measurement at the highest electric field prior to breakdown and the test was performed up to 200℃. The energy storage performance of BSTS- x BZN with different BZN content x=0~0.15 is given in Supporting Materials A. The optimal performance occurs at BSTS-0.11BZN, which exhibits an outstanding combination of excellent room-temperature energy storage performance (U e ~8.5 J/cm 3 ,η>90%) with high thermal stability up to 200℃ (at which a high U e ~4.85 J/cm 3 , η>90% is maintained) (Fig.2a). The thermal-stability-weighted energy storage performance outperforms existing dielectric materials reported in the literature. The excellent energy storage performance of BSTS-0.11BZN is manifested in its P - E loop (the inset of Fig.2(b)) which is characterized by a slim hysteresis an ultra-high breakdown strength of 690 kV/cm and high polarization up to 27 μC/cm 2 at 60℃, and consequently, the maximum energy density reaches 8.5 J/cm 3 with an efficiency of 94.8% (energy storage performance at other temperatures are shown in the Fig. S2). The combination of high energy-density and high efficiency yields an outstanding figure of merit for BSTS-0.11BZN from room temperature up to 200℃ as compared with existing materials reported in the literature (Fig.2c). The existing Pb-free material systems show a modest Q F ~50 J/cm 3 over a temperature range from 25℃ to 200℃. At room temperature a high Q F material requires a high polarization, high breakdown strength with small hysteresis loss due to domain switching. At high tempeatures Q F tends to have a lower value due to significant loss and lowering of breakdown strength caused by charge transport/leakage, and thus maintaining high Q F requires the suppression of charge transport/leakage at high temperatures, which is challenging. Our BSTS-0.11BZN nanocomposite exhibits a record-high Q F =167 J/cm 3 at room temperature and maintains a fairly high Q F =49 J/cm 3 at 200℃ (obtained from P-E loops in Fig. 2 (d)), which outperforms existing Pb-free materials reported in the literature. Hence, our TRE/AFE nanocomposite may provide a viable solution for the application of energy storage capacitors at stringent temperatures. 2.2. Microstructure characterization In order to understand the origin of the superior energy storage performance of the BSTS-0.11BZN, we made a systematic microscopic investigation by SEM, TEM, XRD and energy-dispersive spectrometer (EDX) over the whole composition range of BSTS- x BZN. The results are depicted in Fig.S1 and Fig.3. The SEM images of BSTS- x BZN (Fig.S1) show clean grain boundaries for x =0~0.13, indicating no macroscopic segregation of BZN between grain interior and boundary. In Fig.3(a), the rhomboid-like stripe nanodomains denoted by dotted circles distributing in TRE matrix are observed in TEM images, which seems the distinguishing appearance of AFE 53,54 . Atomic-resolution TEM micrograph in Fig.3(b) and (c) show that the nano-precipitates are AFE and the matrix phase is TRE nanodomains with a mixture of T, O/R polar symmetries, and the interface between AFE and TRE is coherent. The polar directions associated with each nanoregion in Fig.3(b) are denoted by arrows, which is determined by the shift of the B-site ion as revealed in the enlarged images Fig.3(c1)-(c4). The TRE character of matrix is also evidenced by line-scanning convergent beam electron diffraction (CBED) as shown in Fig.S3. The TRE character of the samples is also consistent with enhanced dielectric permittivity shown in Fig.S4, which stems from easy domain rotation due to tricriticality, as reported in our previous work 15 . The nature of the nano-precipitates being AFE is directly revealed by atomic-resolution TEM image shown in Fig.3(c4) where the anti-phase ionic shift is shown with arrows. The AFE nature is further verified by TEM diffraction pattern and synchrotron-XRD as shown in Fig.3(d-e), which reveal characteristic 1/2(310) AFE superlattice reflections in both electron diffraction (Fig.3(d)) and synchrotron XRD spectrum (Fig.3(e)). Such a unique nanocomposite structure originates from nanoscale compositional segregation as shown by local elemental mapping using high-angle annular dark field and corresponding EDX (HADDF-EDX) in Fig.3(f), which reveals that Bi 3+ and Zn 2+ are richer in AFE regions than in TRE matrix. Therefore, the self-organizing nanocomposite structure is caused by the nanoscale chemical inhomogeneity. The formation of AFE nanoparticles occurs in Bi 3+ and Zn 2+ enriched nano-regions where favorable conditions to form AFE (smaller A site ion (Bi 3+ ) and larger B-site ion (Zn 2+ )) 55,56 is satisfied. The AFE nano-precipitate serve as nanofillers into the TRE matrix, which can form charge traps at AFE/TRE interfaces. This situation resembles that in another nano-composite made of nano-inorganic fillers and polymer matrix. According to muliticore model and potential barrier model, nanointerfaces between fillers and matrix would form charge traps to capture mobile charges 57–61 . Moreover, the band gap increases with a decrease in tolerance factor 60,62 . These effects lead to a high resistivity and high breakdown strength of the AFE-TRE nanocomposite. The interfacial trapping effect explains the increase of breakdown strength E b with increasing AFE fraction up to x =0.11 (AFE fraction is calculated from XRD results shown in Fig.S5). Nevertheless, further increase in x causes E b to decrease due to inhomogeneous precipitation of BZN at grain boundaries (Fig.S1). Therefore, the outstanding breakdown strength of BSTS-0.11BZN and its low conductive loss originate from the AFE-TRE nanocomposite which reduces mobile charge carriers – the source of conductive loss and electrical breakdown; these contribute to a higher electric storage performance at both room temperature and high temperature. Furthermore, the thermal stability of the peculiar microstructure was investigated by in-situ heating TEM observation, and the weak beam (the direction selected (002) which marked in red circle at Fig.4 (a4) bottom right) dark field images at 25℃, 100℃, 150℃ and 200℃ were presented in Fig.4 (a1-a4), respectively. It is evident that the AFE nanoparticles (green arrow pointed area) and TRE nanodomains (red arrow pointed area) remain unchanged within the test temperature range, indicating an impressive thermal stability of these microstructures. The thermal insensitivity should be ascribed to the random local field confining the high-temperature phase transition. It is also confirmed by the broadened temperature-dependence of dielectric permittivity as presented in Fig.S4. 2.3. Evolution of domain structures in response to electric field To further explore the evolution of multiple types of nanodomains with external electric field, we did PFM measurements and phase-field modeling for the BSTS-0.11BZN specimens. The local polarization states are mapped by PFM phase images with the voltage applied between conductive tip and substrate as presented in Fig.5(a). The TRE nanodomains are sensitive to external field that they were poled to one orientation under low tip voltage (10 V). The TRE nanodomains are also highly recoverable under the decreasing tip voltage process as shown in Fig.S6, which rationalize the slim polarization hysteresis and high efficiency performance. On the other hand, the AFE nanoparticles remain inert to external field up to 50 V (approximately equal to 580 kV/cm as calculated in Fig. S7), contributing to stable AFE/TRE nanointerface 63,64 . Fig.5(b-d) shows the calculated microstructural evolution of BSTS-0.11BZN under external electric field by phase field modeling. Microstructure of polarization in self-organizing TRE/AFE nanocomposites are presented in Fig.5(b), in which the gray color describes the paraelectric phase without spontaneous polarization, and chromatic colors show the ferroelectric phase with different spontaneous polarization alignments with arrows describing the polarization direction. The nanodomain configuration evolution upon electric field loading (①-④) and unloading (④-⑦) are shown in Fig.5(c) with corresponding P-E loop in Fig.5(d). The results indicate that the TRE nanodomains are polarized and AFE nanodomains remaining inert; the microstructure also shows large degree of recoverability after unloading electric field, which is the origin of the high polarization, breakdown strength with high energy storage efficiency. 2.4. Charge transportation behavior At high temperatures and high electric fields, charge transport (manifested by a low resistivity) becomes severe due to thermal activation and field-enhanced charge transport 65,66 . These effects cause conductive loss through leakage and even electrical breakdown due to impact ionization, thereby deteriorating energy storage performance in particular at high temperatures and high fields. Therefore, to achieve excellent energy storage performance it is essential to overcome the inevitable detrimental effects caused by charge transport. The resistivity (at 20 kV/cm (DC)) and breakdown strength of BSTS-0.11BZN and BSTS are compared from 50℃ to 200℃. As shown in Fig.6(a), BSTS-0.11BZN maintains a high resistivity of ~2.07×10 11 Ω·cm, being 3~5 orders of magnitude higher than that of undoped BSTS over the whole test temperature range. The high resistivity of BSTS-0.11BZN leads to low conduction loss and thus contributes to not only high discharging efficiency 67 (as shown in Fig.2(a1)) but also high breakdown strength. It is imperative to highlight that the exceptionally high resistivity induces a breakdown strength that surpasses BSTS by a factor of three throughout a broad temperature range as shown in Fig. 6 (a). The greatly enhanced resistivity is caused by a significant increase in charge traps in the BSTS-0.11BZN as compared with undoped BSTS. The charge trap density of both materials is assessed by thermally stimulated depolarization current (TSDC) measurement, by which trap energy level ( E a ) and trap density ( N t ) are obtained as presented in supporting materials I. As shown in Fig. 6 (b1) and (b2), shallow traps with E a of 0.33 eV and N t of about 2×10 7 m -3 are observed in both materials, while new deep traps (detrapping current peak at 180℃) with E a of 1.08 eV and N t of about 9×10 6 m -3 emerge in BSTS-0.11BZN. The resistivity and breakdown strength and trap density of BSTS-xBZN with varying BZN contents were further compared at 200℃ in Fig.6 (c). Both the resistivity, breakdown strength and trap density display a notable increase and reach maximum at x=0.11, and then followed by a subsequent decrease with BZN contents addition from 0 to 0.2. These results substantiate that the emerged deep traps are induced by AFE/TRE nanointerfaces, which are able to capture charge carriers like electrons and holes within 180℃, and accordingly are responsible for the enhanced resistivity and breakdown strength at elevated temperatures. With BZN content increasing beyond x=0.11, the AFE phase no longer precipitates homogeneously within grain interior and it begins to distribute preferentially along grain boundaries, as shown in Fig.S1; this causes a reduction of the total AFE/TRE interfaces and thus leading to a decrease in resistivity and breakdown strength. The above results suggest that introducing deep traps induced by the nanocomposite microstructure is an effective approach to control charge transport and improve breakdown strength, particularly at high temperatures. This implies that constructing self-organized nanocomposite with deep traps in other solid solution materials could be a general approach for high temperature energy storage. 3. Conclusion In this work, a self-organized TRE/AFE nanocomposite is designed in BSTS- x BZN relaxors which exhibit superior energy storage performance up to high temperatures. At optimal composition of BSTS-0.11BZN the energy density reaches 8.5 J/cm 3 with a high efficiency η =94.8% (Figure of merit = 167 J/cm 3 ) at 60℃, and a stable energy density about 4.85 J/cm 3 with η >90% (Figure of merit = 49 J/cm 3 ) over a wide temperature range from -10℃ to 200℃. The TRE/AFE nanocomposite is characterized by the coexistence of TRE and coherent AFE nanodomains persisting up to 200℃. The high polarization and low hysteresis loss arise from TRE matrix state and the high resisitivity and high breakdown strength up to high temperatures stem from deep charge traps from the coherent interfaces between AFE and TRE. Therefore, self-organized TRE/AFE nanocomposite may become an effective approach to achieving advanced ceramics with excellent high-temperature energy storage ability. 4. Experimental 4.1. Sample preparation Solid phase sintering method was used to synthesize (1- x )Ba 0.9 Sr 0.05 Ti 0.895 Sn 0.105 O 3 - x Bi 1.5 ZnNb 1.5 O 7 ceramics. Raw materials of BaCO 3 , SrCO 3 , TiO 2 , SnO 2 , Bi 2 O 3 , ZnO, and Nb 2 O 5 powders were well-mixed by ball-milling for 6 h. Then the powders were calcined at 1100℃ for 4 h. After further milling with polyvinyl alcohol (PVA) binder for 1 h, the powders were pressed into green pellets at 2 MPa. The green pellets were sintered at 1200℃ for 2~3 h after burning out the PVA binder at 550℃ for 4 h. The grain size of the samples is around 4 μm as revealed by scanning electron microscopy shown in Fig.S1. Silver electrodes were applied by using silver paste fired at 850°C for 30 min. 4.2. Characterization The temperature dependence of dielectric permittivity was measured using an LCR meter (HIOKI IM3536) connected to a controlled temperature chamber (Delta 9023). The polarization-electric field loops ( P - E loops) were measured at a frequency of 100 Hz by using a ferroelectric workstation (Radiant Precision Multiferroric). Resistivity was measured through a high voltage DC system (with current meter Keithley 6517B) connected with a temperature chamber at an applied electric field of 20 kV/cm. TSDC measurements were performed to characterize charge traps of materials (concept 90). The samples for TSDC measurements were poled at 20℃ for 10 min under a DC electric field of 10 kV/cm, and then rapidly cooled to -100℃ while maintaining electric field, followed by short-circuited and heated at a rate of 2℃/min to 200℃. The structural properties were characterized by synchrotron X-ray diffraction (XRD) and atomic-resolution transmission electron microscopy (TEM). Before the XRD measurements, both surfaces of the samples were polished to a thickness about 500 µm. The synchrotron XRD experiments were carried out at beamline 02U of Shanghai Synchrotron Radiation Facility using Cu Kα X-ray radiation with the wavelength l=0.9538 nm, and the 2D patterns were transformed to 1D curves by Fit2D. The bright field images of morphology and their diffraction patterns were characterized by TEM (FEI, Themis Z), and the local crystal structure were detected by convergent beam electron diffraction (CBED) technique. The local polarization states and their evolution with external electric field are mapped using piezoelectric force microscopy (PFM) (Asylum Research, Cypher ES, Oxford) with conductive probes (Nanoworld, EFM). All the PFM scanning are performed around the resonance frequency (tip‐sample resonance) in DARTSSPFM mode, with the driven AC voltage amplitude of 10 V. Before measurements, the specimens were polished to optical standard. 4.3. Phase-field simulation Phase-field simulations were employed to clarify the microstructural evolution for the self-organized nanocomposite. The total free energy includes the following terms: The term f bulk in Equation (1) describes the bulk free energy density, which can be expressed by Landau free energy term in Equation (2) from the previous study 68–70 . It should be noticed that the multiple terms in Equation (2) decide the stability of ferroelectric phases (T, O, or R) and barriers between different ferroelectric phases, the coefficients of these multiply terms will be zero when the system is at the triple point 71 . The global field effect can be described by the associated coefficients referred 72–78 . The terms f elas , f elec and f grad in Equation(1) reflect the long-range elastic and electrostatic interaction energies and the short-range exchange interaction energy of gradient term respectively. The term f elec = f dipole + f depola + f appl 79–81 , here f dipole is the dipole-dipole interaction caused by polarization, f depola is the depolarization energy density and f appl is the energy density caused by applied electric field. The term f LFE represents the local field effect caused by doped defects, where a random number with different polarization directions have been considered in our simulation 79 . The temporal evolution of the spontaneous polarization field can be obtained by solving the time-dependent Ginzburg-Landau (TDGL) function as Equation (3): The domain structure is described by a distribution of spontaneous polarization P = ( P 1 , P 2 , P 3 ). Further mathematical transformation was employed to obtain the symmetry contours from the calculated vector maps. Declarations Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. Acknowledgements Y. Liu and J. Xu contributed equally to this work. The authors are thankful for the kindly help on synchrotron XRD measurements from Xingmin Zhang in Shanghai Synchrotron Radiation Facility. The authors acknowledge the help on experiments of TEM from Andong Xiao, the help on experiments of sample preparation from Siyan Yu and the help on PFM from Tianzi Yang and Guanqi Wang. J. Gao acknowledges the Fundamental Research Funds for the Central Universities of China (xtr042019002) and the Natural Science Foundation of Ordos (2021EEDSCXQDFZ014) for financial support. Y. Liu acknowledges the National Natural Science Foundation of China (Grant No. 52207031) and the Fundamental Research Funds of Xian Jiaotong University (xzy012021022). References Pan, H. et al. 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Strong electrocaloric effect in lead-free 0.65Ba(Zr 0.2 Ti 0.8 )O 3 -0.35(Ba 0.7 Ca 0.3 )TiO 3 ceramics obtained by direct measurements. Appl. Phys. Lett. 106 , 062901 (2015). Luo, Z. et al. Enhanced electrocaloric effect in lead-free BaTi 1 − x Sn x O 3 ceramics near room temperature. Appl. Phys. Lett. 105 , 102904 (2014). Additional Declarations There is NO Competing Interest. Supplementary Files supportingmaterials240203.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3926354","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":271352761,"identity":"eafafda5-e1d7-4996-a29e-d910ece468af","order_by":0,"name":"Jinghui Gao","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+klEQVRIiWNgGAWjYJACgwQGhgQGZuYDDBJgfgLRWtgSGCQSiNQCVcZjAFVNQIu8++EDBQ931OYZHOf5JmH54zADP3uOAcPPHbi1GJ5JSzBIPHO82OAw72YDiYTDDJI9bwwYe8/g0dKQY2CQ2HYsccNh3o0PQFoMbuQYMDO24dHS/wamhefBAZAWe0Ja5CXAttSAtDBCbJEgoMVA4hnQL20HEmceZjM2kEhL55E486zgYC8+W/qTjxn+bKtL7Dt/+Jm0hI21HH978sYHP/HZcoCBDRgfh8EcZmDs84AYB3BrANrSwMD8gIGhDsxh/IBP6SgYBaNgFIxYAADsMlSidp5tVwAAAABJRU5ErkJggg==","orcid":"","institution":"State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China","correspondingAuthor":true,"prefix":"","firstName":"Jinghui","middleName":"","lastName":"Gao","suffix":""},{"id":271352762,"identity":"67e80481-597c-4a70-ab73-806a85199faf","order_by":1,"name":"Jingzhe Xu","email":"","orcid":"","institution":"State Key Laboratory of Electrical Insulation, Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Jingzhe","middleName":"","lastName":"Xu","suffix":""},{"id":271352763,"identity":"3e2f3c7d-6c35-419b-9cd5-cf0f6422d8c2","order_by":2,"name":"Yongbin Liu","email":"","orcid":"https://orcid.org/0000-0001-8358-7342","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yongbin","middleName":"","lastName":"Liu","suffix":""},{"id":271352764,"identity":"c786d038-442d-477b-9a56-b6b2f88ca783","order_by":3,"name":"Dong Wang","email":"","orcid":"https://orcid.org/0000-0001-6009-166X","institution":"Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Dong","middleName":"","lastName":"Wang","suffix":""},{"id":271352765,"identity":"034ede26-4b0c-4e2c-bc12-dfdd9205c8c4","order_by":4,"name":"Li He","email":"","orcid":"","institution":"School of Automation and Information Engineering, Xi’an University of Technology","correspondingAuthor":false,"prefix":"","firstName":"Li","middleName":"","lastName":"He","suffix":""},{"id":271352766,"identity":"fba9e3e6-1171-4c89-9436-0aa3a0d9ce2e","order_by":5,"name":"Lisheng Zhong","email":"","orcid":"","institution":"State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China","correspondingAuthor":false,"prefix":"","firstName":"Lisheng","middleName":"","lastName":"Zhong","suffix":""},{"id":271352767,"identity":"554e1db8-696c-488f-ae8a-b43d8002e20a","order_by":6,"name":"Ming Wu","email":"","orcid":"","institution":"State Key Laboratory of Electrical Insulation, Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Ming","middleName":"","lastName":"Wu","suffix":""},{"id":271352768,"identity":"f37364d2-dfed-4750-b171-45c63d28ab8f","order_by":7,"name":"Ruifeng Yao","email":"","orcid":"","institution":"State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China","correspondingAuthor":false,"prefix":"","firstName":"Ruifeng","middleName":"","lastName":"Yao","suffix":""},{"id":271352769,"identity":"3a7451a8-e086-4d93-84d7-159383ab9967","order_by":8,"name":"Nan Zhang","email":"","orcid":"https://orcid.org/0000-0002-8515-429X","institution":"Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Nan","middleName":"","lastName":"Zhang","suffix":""},{"id":271352770,"identity":"679f1ce5-4268-4356-89e1-effe8d735b45","order_by":9,"name":"Xiaojie Lou","email":"","orcid":"https://orcid.org/0000-0002-0603-8451","institution":"Xi'an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Xiaojie","middleName":"","lastName":"Lou","suffix":""},{"id":271352771,"identity":"139ced9b-5db3-45b8-b489-5ed449358d95","order_by":10,"name":"Shengtao Li","email":"","orcid":"","institution":"State Key Laboratory of Electrical Insulation, Xi’an Jiaotong University","correspondingAuthor":false,"prefix":"","firstName":"Shengtao","middleName":"","lastName":"Li","suffix":""},{"id":271352772,"identity":"1df92516-45e2-4a25-8ed6-732947acd3b1","order_by":11,"name":"Xiaobing Ren","email":"","orcid":"https://orcid.org/0000-0002-4973-2486","institution":"National Institute for Materials Science","correspondingAuthor":false,"prefix":"","firstName":"Xiaobing","middleName":"","lastName":"Ren","suffix":""}],"badges":[],"createdAt":"2024-02-04 05:25:28","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-3926354/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-3926354/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":51334024,"identity":"298bbe13-d606-4ea2-bcba-646ca855948c","added_by":"auto","created_at":"2024-02-19 18:25:24","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":186327,"visible":true,"origin":"","legend":"\u003cp\u003eThe design strategy of self-organized trirelaxor(TRE)/antiferroelectric(AFE) nanocomposite with enhanced energy performance. (a1) Mixing tricritical ferroelectric former and AFE inducer. (a2) Composition segregation of AFE inducer ions during calcining/sintering. (a3) The formation of self-organized TRE/AFE nanocomposite through nanoscale phase separation. (b1) Conventional relaxor showing thermal degradation issues of high energy barrier and charge transportation, which results in low energy storage performance at high temperature. (b2) Material design strategy of self-organized TRE/AFE nanocomposite. TRE matrix ensures high polarization and high energy efficiency due to flat energy landscape from tricriticality and these high performance can persist to high temperatures due to large random local fields by dissolved AFE in the TRE matrix. The formation of AFE nano-particles significantly increases breakdown strength through creating high-density AFE/TRE interfaces, which act as deep traps for charge carriers; this contributes to high energy-density and high efficiency (low loss).\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/04eb71f93b63d6ae84f73f4c.png"},{"id":51334026,"identity":"d89adb63-0466-464f-adaf-47e388a8124a","added_by":"auto","created_at":"2024-02-19 18:25:24","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":323638,"visible":true,"origin":"","legend":"\u003cp\u003eEnergy storage performance of 0.89Ba\u003csub\u003e0.9\u003c/sub\u003eSr\u003csub\u003e0.05\u003c/sub\u003eTi\u003csub\u003e0.895\u003c/sub\u003eSn\u003csub\u003e0.105\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-0.11Bi\u003csub\u003e1.5\u003c/sub\u003eZnNb\u003csub\u003e1.5\u003c/sub\u003eO\u003csub\u003e7 \u003c/sub\u003e(BSTS-0.11BZN). (a) 3D Locations for the performance of a series of energy storage ceramics\u003csup\u003e11,16–52\u003c/sup\u003e, suggesting BSTS-0.11BZN is superior on the energy storage performance than other counterparts in a wide temperature range. (b) The optimal energy storage performance shows 8.5J/cm\u003csup\u003e3\u003c/sup\u003e in energy density (red) and 94.8% in efficiency (blue) at 60℃ at 100 Hz. (c) Comparison of high temperature energy storage performance for ceramics\u003csup\u003e11,16–52\u003c/sup\u003e. Our BSTS-0.11BZN system shows a record-high figure of merit (c.a. 167) and thermal stability over a wide temperature range (-10℃~200℃). (d) Thermal stable P-E loops of BSTS-0.11BZN over -10℃ to 200℃ at 530 kV/cm.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/4113d8ead991fa81c94d72e8.png"},{"id":51334027,"identity":"ab7a8e75-883b-4281-8594-b14752e1debb","added_by":"auto","created_at":"2024-02-19 18:25:25","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":683513,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructure of self-organized TRE/AFE nanocomposite. (a) TEM bright field image of BSTS-0.11BZN reveals coherent nano-AFE particles (manifested as Moire stripes) distributing in TRE matrix. (b) Atomic-resolution TEM image with [001] incident beam of the coherent AFE-particle/TRE-matrix interface and its enlarged images on (c1)-(c4), the shift of the B-site atomic columns is directly measured to obtain the polar vectors (arrows). (d) Selected area diffraction pattern of AFE regions with [013] incident beam shows 1/2(310) superlattice spots which is characteristic of the AFE phase. (e1) and (e2) Synchrotron XRD spectra for BSTS-0.11BZN; and the 1/2(310) peak reveals the oxygen octahedron tilt associated with the AFE structure. (f1)-(f2) Morphology of an individual AFE nanoparticle in TRE matrix and Bi and Zn content along point 1-7 shown in (f1), suggesting the segregation of Bi and Zn in AFE regions.\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/bb44d5ddee22ea9948423ce0.png"},{"id":51334030,"identity":"6d4a806a-b9e1-4ee8-a903-75af983f4967","added_by":"auto","created_at":"2024-02-19 18:25:26","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1000328,"visible":true,"origin":"","legend":"\u003cp\u003eIn-situ TEM images of BSTS-0.11BZN from 25℃ to 200℃. (a1-a4) AFE nanocomposite coexist with TRE nanodomains at room temperature up to 200°C, signifying an impressive thermal stability of the microstructure.\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/8e16923485ab72d9ebaf7564.png"},{"id":51334028,"identity":"e43412e9-9f50-4468-88aa-9e6e85f0bd56","added_by":"auto","created_at":"2024-02-19 18:25:25","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":723005,"visible":true,"origin":"","legend":"\u003cp\u003eMicrostructural evolution of self-organized TRE/AFE nanocompostie. (a) TRE/AFE domain structure evolution with increasing tip voltages, in which the TRE nanodomains(dark area) switching to external field direction and dark antiferroelectric nanodomains(dotted white area) remain inert even under high electric field. (b) Phase-field modeling of microstructure of TRE/AFE nano-composite, in which gray color represents paraelectric phase without zero polarization, and chromatic colors represent nano polar regions of different spontaneous polarization directions. (c) Evolution of domain configuration during electric field loading (①-④) and unloading (④-⑦) process, which shows high reversibility. (d) The corresponding low hysteretic \u003cem\u003eP\u003c/em\u003e-\u003cem\u003eE\u003c/em\u003eloop calculated from the microstructures.\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/2cf1514741e7df701cef8637.png"},{"id":51334023,"identity":"2ecdd423-55b4-4fd5-8319-0d72c98d06b2","added_by":"auto","created_at":"2024-02-19 18:25:24","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":151334,"visible":true,"origin":"","legend":"\u003cp\u003eCharge transport behavior and charge trap evaluation in TRE/antiferroelectric nanocomposite BSTS-0.11BZN in comparison with undoped BSTS. (a) Temperature dependence of resistivity and breakdown strength. BSTS-0.11BZN exhibits 3-5 orders of magnitude higher resistivity than BSTS, and its breakdown strength was three times higher than BSTS over a temperature range from 50℃ to 200℃. (b) Thermally stimulated depolarization current (TSDC) curves and the corresponding charge traps, showing a deep trap appears at 180℃ caused by nanointerface in BSTS-0.11BZN. (c) Correlation of resistivity and breakdown strength at 200℃ with trap density for different BZN contents suggests that increasing charge traps (i.e., AFE/TRE interface) can effectively increase resistivity and breakdown strength.\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/5aa50bdda04d6d9da5a3ba3f.png"},{"id":74573314,"identity":"6a3db2e9-be74-4eec-8ec0-2d38a0f77ce0","added_by":"auto","created_at":"2025-01-23 14:44:34","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4242694,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/7a35bc70-87d6-45b6-8d93-049b296d2651.pdf"},{"id":51334022,"identity":"2f24ff91-b3ea-41c3-8cda-214215f15a02","added_by":"auto","created_at":"2024-02-19 18:25:23","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":7857743,"visible":true,"origin":"","legend":"","description":"","filename":"supportingmaterials240203.docx","url":"https://assets-eu.researchsquare.com/files/rs-3926354/v1/43b1d241c3ccce6df396e294.docx"}],"financialInterests":"There is \u003cb\u003eNO\u003c/b\u003e Competing Interest.","formattedTitle":"Superior Energy Storage Performance up to 200°C in a Self-organized Trirelaxor-antiferroelectric Nanocomposite","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eElectric energy storage underpins many modern technologies from electric vehicles to advanced pulse power sources. There is a strong demand for an electric energy storage solution that can store large amount of electric energy (i.e., high energy-density) and simultaneously allows for high charging/discharging rate (i.e., high power-density). However, high energy-density and high power-density usually do not go hand in hand. Electric energy storage using electrochemical batteries such as lithum-ion batteries and fuel-cell batteries stores the input electrical energy in the form of chemical energy and thus can achieve high energy density but at the expense of low charging/discharging rate, being limited by the slow electrochemical reaction. To circumvent the low charging/discharging rate issue of electrochemical batteries, there has been a revived interest in electric energy storage by using dielectric capacitors\u003csup\u003e1\u0026ndash;3\u003c/sup\u003e, because such capacitors store the electric energy as it is, i.e., in the form of electric charges; thus in theory the charging/discharging rate is commensurate with the speed of light and the actual rate is limited only by the electrical impedance of the charging/discharging circuit. However, conventional dielectric capacitors can store merely 3-4 order of magnitude smaller amount of energy when compared with electrochemical batteries\u003csup\u003e4,5\u003c/sup\u003e. Thus to make dielectric capacitors a viable solution for high energy-density storage, a leap in its energy-density is required.\u003c/p\u003e\n\u003cp\u003eOver the last decade thin film ceramic capacitors have been shown to significantly enhance the energy density of ceramic capacitors by 1-2 order of magnitude\u003csup\u003e1,6\u003c/sup\u003e owing mostly to their exceedingly high breakdown strength as compared with that of bulk ceramics. These encouraging results have provided new impetus for exploring the potentials of dielectric capacitors\u003csup\u003e7\u0026ndash;10\u003c/sup\u003e. However, since existing thin film capacitors are composed of a single-layer film (nanometer in thickness) deposited on a bulk substrate (~1 mm in thickness), the averaged energy-density of the film+substrate system is reduced by 4-5 orders of magnitude despite the high energy density within the film\u003csup\u003e10\u003c/sup\u003e. This issue renders the existing thin film capacitors technologically unviable for energy storage at present. For this reason, there is increasing interest in high-performance dielectric bulk capacitors\u003csup\u003e3,11\u003c/sup\u003e because bulk capacitors and its derivative \u0026ndash; multi-layer ceramic capacitors (MLCC) can be mass-produced with mature ceramics technology and advances in dielectric materials can be easily scalable to industrial lines.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eBulk ceramic capacitors and MLCC are mostly based on relaxor ferroelectrics because their relaxor transition temperature can be easily tailered to occur around room temperature where a mediocre and broad permittivity peak (i.e., temperature-insensitive) is achieved together with low loss\u003csup\u003e9,12,13\u003c/sup\u003e. However, a major challenge for this type of materials is to maintain high energy-density and low loss up to sufficiently high ambient temperatures (e.g., 200℃), because energy storage devices usually experience self-heating due to the heat dissipation of the system and sometimes the devices need to work in high-temperature environment. This challenge arises from the inevitable vanishing of polar nano-regions (PNRs, which contribute to high polarization) and the occurrence of charge transport (which leads to high loss and low electrical breakdown strength) at high temperatures. Consequently these detrimental effects at high temperatures render low energy storage ability and low efficiency of ceramic capacitors at high temperatures. Despite significant efforts in recent years\u003csup\u003e14\u003c/sup\u003e, an effective strategy that can simultaneously maintain high-polarization state and reduce charge transport at high temperatures is lacking.\u003c/p\u003e\n\u003cp\u003eIn recent years, a special type of relaxor materials called trirelaxor has been found to demonstrate outstanding permittivity around their trirelaxor transition temperature as compared with the normal relaxors\u003csup\u003e15\u003c/sup\u003e. Being different from a relaxor which is characterized by a single type of PNRs, a trirelaxor is a mixture state of PNRs with different polar symmetries of tetragonal, orthorthombic, rhombohedral; it is reminiscent of a tricritical point (TCP) modified by relaxor-forming dopants. Compared with a normal relaxor, a trirelaxor exhibits much high permittivity around its trirelaxor transition temperature yet maintaining temperature-insensitivity like a common relaxor. Therefore, trirelaxor materials may become a promising solution to energy storage demand due to their higher permittivity as compared with normal relaxors. However, trirelaxors also suffer from similar thermal degradation issues with those of common relaxors due to leakage current and dielectric breakdown. Thus trirelaxor alone cannot guarantee high energy storage ability and high storage efficiency up to high temperatures.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eHere we propose a strategy to achieve simultaneously excellent room-temperature energy-storage ability and outstanding resistance against thermal degradation by forming a self-organized nanocomposite composed of trirelaxor (TRE) matrix and antiferroelectric (AFE) nanoscale phases. A TRE/AFE nanocomposite based on (1-x)(Ba,Sr)(Ti,Sn)O\u003csub\u003e3\u003c/sub\u003e-xBi\u003csub\u003e1.5\u003c/sub\u003eZnNb\u003csub\u003e1.5\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e (BSTS-BZN) system (x=0~20%) shows not only excellent room-temperature energy storage performance (energy density U\u003csub\u003ee\u003c/sub\u003e=8.5 J/cm\u003csup\u003e3\u003c/sup\u003e, efficiency \u0026eta;=94.8%, figure of merit Q\u003csub\u003eF\u003c/sub\u003e=167 J/cm\u003csup\u003e3\u003c/sup\u003e) but also strong resistance against performance deterioration at high temperature:\u0026nbsp;the material exhibits superior high energy storage performance (U\u003csub\u003ee\u003c/sub\u003e=4.85 J/cm\u003csup\u003e3\u003c/sup\u003e and \u0026eta;=90.3%, Q\u003csub\u003eF\u003c/sub\u003e=49 J/cm\u003csup\u003e3\u003c/sup\u003e) even at 200\u0026deg;C, which outperforms existing Pb-free dielectric materials.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe material design strategy is illustrated in Fig.1. Suitable starting materials (oxides and carbonates) are selected so as to form to a mixture consisting of tricritical ferroelectric material (Ba,Sr)(Ti,Sn)O\u003csub\u003e3\u003c/sub\u003e composition and the AFE inducer (Bi\u003csub\u003e1.5\u003c/sub\u003eZnNb\u003csub\u003e1.5\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e) composition (in Fig. 1(a1)). By controlling the calcining and sintering conditions, the dissolved Bi\u003csup\u003e3+\u003c/sup\u003e, Zn\u003csup\u003e2+\u003c/sup\u003e and Nb\u003csup\u003e5+\u003c/sup\u003e ions undergo a nanoscale phase separation which leads to a self-organized nanocomposite composed of nano-sized AFE particles (BZN-rich) embedded into a TRE matrix BST (BZN-poor) shown in Fig. 1(a2)-(a3). The tricriticality of BST has been reported to flatten the energy barriers which overcome the energy loss and high energy barriers issues in conventional relaxor (in Fig. 1(b1)) and thus leading to high polarization response and high energy storage efficiency, and strong random fields by BZN changes the tri-critical ferroelectric matrix into a TRE matrix with highly stable TRE nanodomains that can persist to high temperatures (shown in Fig. 1(b2)). As the result, the BZN-doped TRE matrix can ensure high polarization response of the system up to high temperatures. On the other hand, the formation of coherent AFE nanoparticles introduces high-density nanointerfaces between AFE and TRE matrix, which act as deep traps to charge carriers (holes and electrons) and thus lead to low leakage and high breakdown strength at both room temperature and high temperatures. As the result, high energy storage efficiency (i.e., low loss) and high breakdown strength can be achieved up to high temperatures in our system when compared with conventional ferroelectrics and relaxors.\u003c/p\u003e"},{"header":"2. Results And Discussion","content":"\u003cp\u003e\u003cstrong\u003e2.1. Energy storage performance from room temperature up to 200℃\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo characterize the energy storage performance of BSTS-\u003cem\u003ex\u003c/em\u003eBZN, the energy density, charging/discharging energy efficiency and figure of merit (Q\u003csub\u003eF\u003c/sub\u003e= U\u003csub\u003ee\u003c/sub\u003e/(1-\u0026eta;) reflects how good a capacitor can store electrical energy against lossy dissipation\u003csup\u003e1,1\u003c/sup\u003e\u003csup\u003e1,13\u003c/sup\u003e) are obtained by \u003cem\u003eP\u003c/em\u003e-\u003cem\u003eE\u003c/em\u003e measurement at the highest electric field prior to breakdown and the test was performed up to 200℃. The energy storage performance of BSTS-\u003cem\u003ex\u003c/em\u003eBZN with different BZN content x=0~0.15 is given in Supporting Materials A. The optimal performance occurs at BSTS-0.11BZN, which exhibits an outstanding combination of excellent room-temperature energy storage performance (U\u003csub\u003ee\u003c/sub\u003e ~8.5 J/cm\u003csup\u003e3\u003c/sup\u003e,\u0026eta;\u0026gt;90%) with high thermal stability up to 200℃ (at which a high U\u003csub\u003ee\u0026nbsp;\u003c/sub\u003e~4.85 J/cm\u003csup\u003e3\u003c/sup\u003e, \u0026eta;\u0026gt;90% is maintained) (Fig.2a). The thermal-stability-weighted energy storage performance outperforms existing dielectric materials reported in the literature.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe excellent energy storage performance of BSTS-0.11BZN is manifested in its \u003cem\u003eP\u003c/em\u003e-\u003cem\u003eE\u003c/em\u003e loop (the inset of Fig.2(b)) which is characterized by a slim hysteresis an ultra-high breakdown strength of 690 kV/cm and high polarization up to 27 \u0026mu;C/cm\u003csup\u003e2\u003c/sup\u003e at 60℃, and consequently, the maximum energy density reaches 8.5 J/cm\u003csup\u003e3\u003c/sup\u003e with an efficiency of 94.8% (energy storage performance at other temperatures are shown in the Fig. S2).\u003c/p\u003e\n\u003cp\u003eThe combination of high energy-density and high efficiency yields an outstanding figure of merit for BSTS-0.11BZN from room temperature up to 200℃ as compared with existing materials reported in the literature (Fig.2c). The existing Pb-free material systems show a modest Q\u003csub\u003eF\u003c/sub\u003e~50 J/cm\u003csup\u003e3\u003c/sup\u003e\u003csub\u003e\u0026nbsp;\u003c/sub\u003eover a temperature range from 25℃ to 200℃. At room temperature a high Q\u003csub\u003eF\u003c/sub\u003e material requires a high polarization, high breakdown strength with small hysteresis loss due to domain switching. At high tempeatures Q\u003csub\u003eF\u003c/sub\u003e tends to have a lower value due to significant loss and lowering of breakdown strength caused by charge transport/leakage, and thus maintaining high Q\u003csub\u003eF\u003c/sub\u003e requires the suppression of charge transport/leakage at high temperatures, which is challenging. Our BSTS-0.11BZN nanocomposite exhibits a record-high Q\u003csub\u003eF\u003c/sub\u003e=167\u003csup\u003e\u0026nbsp;\u003c/sup\u003eJ/cm\u003csup\u003e3\u003c/sup\u003e\u003csub\u003e\u0026nbsp;\u003c/sub\u003eat room temperature and maintains a fairly high Q\u003csub\u003eF\u003c/sub\u003e=49 J/cm\u003csup\u003e3\u003c/sup\u003e\u003csub\u003e\u0026nbsp;\u003c/sub\u003eat 200℃ (obtained from P-E loops in Fig. 2 (d)), which outperforms existing Pb-free materials reported in the literature. Hence, our TRE/AFE nanocomposite may provide a viable solution for the application of energy storage capacitors at stringent temperatures.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.2. Microstructure characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn order to understand the origin of the superior energy storage performance of the BSTS-0.11BZN, we made a systematic microscopic investigation by SEM, TEM, XRD and energy-dispersive spectrometer (EDX) over the whole composition range of BSTS-\u003cem\u003ex\u003c/em\u003eBZN. The results are depicted\u0026nbsp;in Fig.S1 and Fig.3. The SEM images of BSTS-\u003cem\u003ex\u003c/em\u003eBZN (Fig.S1) show clean grain boundaries for \u003cem\u003ex\u003c/em\u003e=0~0.13, indicating no macroscopic segregation of BZN between grain interior and boundary.\u0026nbsp;In Fig.3(a), the rhomboid-like stripe nanodomains denoted by dotted circles distributing in TRE matrix are observed in TEM images, which seems the distinguishing appearance of AFE\u003csup\u003e53,54\u003c/sup\u003e. Atomic-resolution TEM micrograph in Fig.3(b) and (c) show that the nano-precipitates are AFE and the matrix phase is TRE nanodomains with a mixture of T, O/R polar symmetries, and the interface between AFE and TRE is coherent. The polar directions associated with each nanoregion in Fig.3(b) are denoted by arrows, which is determined by the shift of the B-site ion as revealed in the enlarged images Fig.3(c1)-(c4). The TRE character of matrix is also evidenced by line-scanning convergent beam electron diffraction (CBED) as shown in Fig.S3. The TRE character of the samples is also consistent with enhanced dielectric permittivity shown in Fig.S4, which stems from easy domain rotation due to tricriticality, as reported in our previous work\u003csup\u003e15\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eThe nature of the nano-precipitates being AFE is directly revealed by atomic-resolution TEM image shown in Fig.3(c4) where the anti-phase ionic shift is shown with arrows. The AFE nature is further verified by TEM diffraction pattern and synchrotron-XRD as shown in Fig.3(d-e), which reveal characteristic 1/2(310) AFE superlattice reflections in both electron diffraction (Fig.3(d)) and synchrotron XRD spectrum (Fig.3(e)).\u003c/p\u003e\n\u003cp\u003eSuch a unique nanocomposite structure originates from nanoscale compositional segregation as shown by local elemental mapping using high-angle annular dark field and corresponding EDX (HADDF-EDX) in Fig.3(f), which reveals that Bi\u003csup\u003e3+\u003c/sup\u003e and Zn\u003csup\u003e2+\u003c/sup\u003e are richer in AFE regions than in TRE matrix. Therefore, the self-organizing nanocomposite structure is caused by the nanoscale chemical inhomogeneity. The formation of AFE nanoparticles occurs in Bi\u003csup\u003e3+\u003c/sup\u003e and Zn\u003csup\u003e2+\u003c/sup\u003e enriched nano-regions where favorable conditions to form AFE (smaller A site ion (Bi\u003csup\u003e3+\u003c/sup\u003e) and larger B-site ion (Zn\u003csup\u003e2+\u003c/sup\u003e))\u003csup\u003e55,56\u003c/sup\u003e is satisfied.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe AFE nano-precipitate serve as nanofillers into the TRE matrix, which can form charge traps at AFE/TRE interfaces. This situation resembles that in another nano-composite made of nano-inorganic fillers and polymer matrix. According to muliticore model and potential barrier model, nanointerfaces between fillers and matrix would form charge traps to capture mobile charges\u003csup\u003e57\u0026ndash;61\u003c/sup\u003e. Moreover, the band gap increases with a decrease in tolerance factor\u003csup\u003e60,62\u003c/sup\u003e. These effects lead to a high resistivity and high breakdown strength of the AFE-TRE nanocomposite. The interfacial trapping effect explains the increase of breakdown strength \u003cem\u003eE\u003c/em\u003e\u003csub\u003eb\u003c/sub\u003e with increasing AFE fraction up to \u003cem\u003ex\u003c/em\u003e=0.11 (AFE fraction is calculated from XRD results shown in Fig.S5). Nevertheless, further increase in \u003cem\u003ex\u003c/em\u003e causes \u003cem\u003eE\u003c/em\u003e\u003csub\u003eb\u003c/sub\u003e to decrease due to inhomogeneous precipitation of BZN at grain boundaries (Fig.S1). Therefore, the outstanding breakdown strength of BSTS-0.11BZN and its low conductive loss originate from the AFE-TRE nanocomposite which reduces mobile charge carriers \u0026ndash; the source of conductive loss and electrical breakdown; these contribute to a higher electric storage performance at both room temperature and high temperature.\u003c/p\u003e\n\u003cp\u003eFurthermore, the thermal stability of the peculiar microstructure was investigated by in-situ heating TEM observation, and the weak beam (the direction selected (002) which marked in red circle at Fig.4 (a4) bottom right) dark field images at 25℃, 100℃, 150℃ and 200℃ were presented in Fig.4 (a1-a4), respectively. It is evident that the AFE nanoparticles (green arrow pointed area) and TRE nanodomains (red arrow pointed area) remain unchanged within the test temperature range, indicating an impressive thermal stability of these microstructures. The thermal insensitivity should be ascribed to the random local field confining the high-temperature phase transition. It is also confirmed by the broadened temperature-dependence of dielectric permittivity as presented in Fig.S4.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.3. Evolution of domain structures in response to electric field\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo further explore the evolution of multiple types of nanodomains with external electric field, we did PFM measurements and phase-field modeling for the BSTS-0.11BZN specimens.\u0026nbsp;The local polarization states are mapped by PFM phase images with the voltage applied between conductive tip and substrate as presented in Fig.5(a). The TRE nanodomains are sensitive to external field that they were poled to one orientation under low tip voltage (10 V). The TRE nanodomains are also highly recoverable under the decreasing tip voltage process as shown in Fig.S6, which rationalize the slim polarization hysteresis and high efficiency performance. On the other hand, the AFE nanoparticles remain inert to external field up to 50 V (approximately equal to 580 kV/cm as calculated in Fig. S7), contributing to stable AFE/TRE nanointerface\u003csup\u003e63,64\u003c/sup\u003e.\u003c/p\u003e\n\u003cp\u003eFig.5(b-d) shows the calculated microstructural evolution of BSTS-0.11BZN under external electric field by phase field modeling. Microstructure of polarization in self-organizing TRE/AFE nanocomposites are presented in Fig.5(b), in which the gray color describes the paraelectric phase without spontaneous polarization, and chromatic colors show the ferroelectric phase with different spontaneous polarization alignments with arrows describing the polarization direction. The nanodomain configuration evolution upon electric field loading (①-④) and unloading (④-⑦) are shown in Fig.5(c) with corresponding P-E loop in Fig.5(d). The results indicate that the TRE nanodomains are polarized and AFE nanodomains remaining inert; the microstructure also shows large degree of recoverability after unloading electric field, which is the origin of the high polarization, breakdown strength with high energy storage efficiency.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e2.4. Charge transportation behavior\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAt high temperatures and high electric fields, charge transport (manifested by a low resistivity) becomes severe due to thermal activation and field-enhanced charge transport\u003csup\u003e65,66\u003c/sup\u003e. These effects cause conductive loss through leakage and even electrical breakdown due to impact ionization, thereby deteriorating energy storage performance in particular at high temperatures and high fields. Therefore, to achieve excellent energy storage performance it is essential to overcome the inevitable detrimental effects caused by charge transport.\u003c/p\u003e\n\u003cp\u003eThe resistivity (at 20 kV/cm (DC)) and breakdown strength of BSTS-0.11BZN and BSTS are compared from 50℃ to 200℃. As shown in Fig.6(a), BSTS-0.11BZN maintains a high resistivity of ~2.07\u0026times;10\u003csup\u003e11\u003c/sup\u003e \u0026Omega;\u0026middot;cm, being 3~5 orders of magnitude higher than that of undoped BSTS over the whole test temperature range. The high resistivity of BSTS-0.11BZN leads to low conduction loss and thus contributes to not only high discharging efficiency\u003csup\u003e67\u003c/sup\u003e (as shown in Fig.2(a1)) but also high breakdown strength. It is imperative to highlight that the exceptionally high resistivity induces a breakdown strength that surpasses BSTS by a factor of three throughout a broad temperature range as shown in Fig. 6 (a).\u003c/p\u003e\n\u003cp\u003eThe greatly enhanced resistivity is caused by a significant increase in charge traps in the BSTS-0.11BZN as compared with undoped BSTS. The charge trap density of both materials is assessed by thermally stimulated depolarization current (TSDC) measurement, by which trap energy level (\u003cem\u003eE\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e) and trap density (\u003cem\u003eN\u003c/em\u003e\u003csub\u003et\u003c/sub\u003e) are obtained as presented in supporting materials I. As shown in Fig. 6 (b1) and (b2), shallow traps with \u003cem\u003eE\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e of 0.33 eV and \u003cem\u003eN\u003c/em\u003e\u003csub\u003et\u003c/sub\u003e of about 2\u0026times;10\u003csup\u003e7\u003c/sup\u003e m\u003csup\u003e-3\u003c/sup\u003e are observed in both materials, while new deep traps (detrapping current peak at 180℃) with \u003cem\u003eE\u003c/em\u003e\u003csub\u003ea\u003c/sub\u003e of 1.08 eV and \u003cem\u003eN\u003c/em\u003e\u003csub\u003et\u003c/sub\u003e of about 9\u0026times;10\u003csup\u003e6\u003c/sup\u003e m\u003csup\u003e-3\u003c/sup\u003e emerge in BSTS-0.11BZN. The resistivity and breakdown strength and trap density of BSTS-xBZN with varying BZN contents were further compared at 200℃ in Fig.6 (c). Both the resistivity, breakdown strength and trap density display a notable increase and reach maximum at x=0.11, and then followed by a subsequent decrease with BZN contents addition from 0 to 0.2. These results substantiate that the emerged deep traps are induced by AFE/TRE nanointerfaces, which are able to capture charge carriers like electrons and holes within 180℃, and accordingly are responsible for the enhanced resistivity and breakdown strength at elevated temperatures. With BZN content increasing beyond x=0.11, the AFE phase no longer precipitates homogeneously within grain interior and it begins to distribute preferentially along grain boundaries, as shown in Fig.S1; this causes a reduction of the total AFE/TRE interfaces and thus leading to a decrease in resistivity and breakdown strength.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe above results suggest that introducing deep traps induced by the nanocomposite microstructure is an effective approach to control charge transport and improve breakdown strength, particularly at high temperatures. This implies that constructing self-organized nanocomposite with deep traps in other solid solution materials could be a general approach for high temperature energy storage.\u0026nbsp;\u003c/p\u003e"},{"header":"3. Conclusion","content":"\u003cp\u003eIn this work, a self-organized TRE/AFE nanocomposite is designed in BSTS-\u003cem\u003ex\u003c/em\u003eBZN relaxors which exhibit superior energy storage performance up to high temperatures. At optimal composition of BSTS-0.11BZN the energy density reaches 8.5 J/cm\u003csup\u003e3\u003c/sup\u003e with a high efficiency \u003cem\u003e\u0026eta;\u003c/em\u003e=94.8% (Figure of merit = 167 J/cm\u003csup\u003e3\u003c/sup\u003e) at 60℃, and a stable energy density about 4.85 J/cm\u003csup\u003e3\u003c/sup\u003e with \u003cem\u003e\u0026eta;\u003c/em\u003e\u0026gt;90% (Figure of merit = 49 J/cm\u003csup\u003e3\u003c/sup\u003e) over a wide temperature range from -10℃ to 200℃. The TRE/AFE \u0026nbsp;nanocomposite is characterized by the coexistence of TRE and coherent AFE nanodomains persisting up to 200℃. The high polarization and low hysteresis loss arise from TRE matrix state and the high resisitivity and high breakdown strength up to high temperatures stem from deep charge traps from the coherent interfaces between AFE and TRE. Therefore, self-organized TRE/AFE nanocomposite may become an effective approach to achieving advanced ceramics with excellent high-temperature energy storage ability.\u003c/p\u003e"},{"header":"4. Experimental","content":"\u003cp\u003e\u003cstrong\u003e4.1. Sample preparation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSolid phase sintering method was used to synthesize (1-\u003cem\u003ex\u003c/em\u003e)Ba\u003csub\u003e0.9\u003c/sub\u003eSr\u003csub\u003e0.05\u003c/sub\u003eTi\u003csub\u003e0.895\u003c/sub\u003eSn\u003csub\u003e0.105\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e-\u003cem\u003ex\u003c/em\u003eBi\u003csub\u003e1.5\u003c/sub\u003eZnNb\u003csub\u003e1.5\u003c/sub\u003eO\u003csub\u003e7\u0026nbsp;\u003c/sub\u003eceramics. Raw materials of BaCO\u003csub\u003e3\u003c/sub\u003e, SrCO\u003csub\u003e3\u003c/sub\u003e, TiO\u003csub\u003e2\u003c/sub\u003e, SnO\u003csub\u003e2\u003c/sub\u003e, Bi\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e, ZnO, and Nb\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e5\u003c/sub\u003e powders were well-mixed by ball-milling for 6 h. Then the powders were calcined at 1100℃ for 4 h. After further milling with polyvinyl alcohol (PVA) binder for 1 h, the powders were pressed into green pellets at 2 MPa. The green pellets were sintered at 1200℃ for 2~3 h after burning out the PVA binder at 550℃ for 4 h. The grain size of the samples is around 4 μm as revealed by scanning electron microscopy shown in Fig.S1. Silver electrodes were applied by using silver paste fired at 850°C for 30 min.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.2. Characterization\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe temperature dependence of dielectric permittivity was measured using an LCR meter (HIOKI IM3536) connected to a controlled temperature chamber (Delta 9023). The polarization-electric field loops (\u003cem\u003eP\u003c/em\u003e-\u003cem\u003eE\u003c/em\u003e loops) were measured at a frequency of 100 Hz by using a ferroelectric workstation (Radiant Precision Multiferroric). Resistivity was measured through a high voltage DC system (with current meter Keithley 6517B) connected with a temperature chamber at an applied electric field of 20 kV/cm. TSDC measurements were performed to characterize charge traps of materials (concept 90). The samples for TSDC measurements were poled at 20℃ for 10 min under a DC electric field of 10 kV/cm, and then rapidly cooled to -100℃ while maintaining electric field, followed by short-circuited and heated at a rate of 2℃/min to 200℃.\u003c/p\u003e\n\u003cp\u003eThe structural properties were characterized by synchrotron X-ray diffraction (XRD) and atomic-resolution transmission electron microscopy (TEM). Before\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003ethe XRD measurements, both surfaces of the samples were polished to a thickness about 500 µm. The synchrotron XRD experiments were carried out at beamline 02U of Shanghai Synchrotron Radiation Facility using Cu Kα X-ray radiation with the wavelength l=0.9538 nm, and the 2D patterns were transformed to 1D curves by Fit2D. The bright field images of morphology and their diffraction patterns were characterized by TEM (FEI, Themis Z), and the local crystal structure were detected by convergent beam electron diffraction (CBED) technique.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe local polarization states and their evolution with external electric field are mapped using piezoelectric force microscopy (PFM) (Asylum Research, Cypher ES, Oxford) with conductive probes (Nanoworld, EFM). All the PFM scanning are performed around the resonance frequency (tip‐sample resonance) in DARTSSPFM mode, with the driven AC voltage amplitude of 10 V. Before measurements, the specimens were polished to optical standard.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e4.3. Phase-field simulation\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003ePhase-field simulations were employed to clarify the microstructural evolution for the self-organized nanocomposite. The total free energy includes the following terms:\u003c/p\u003e\n\u003cp\u003e\u003cimg 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\" width=\"586\" height=\"91\"\u003e\u003cbr\u003e\u003c/p\u003e\n\u003cp\u003eThe term \u003cem\u003ef\u003c/em\u003e\u003csub\u003ebulk\u003c/sub\u003e in Equation (1) describes the bulk free energy density, which can be expressed by Landau free energy term in Equation (2) from the previous study\u003csup\u003e68–70\u003c/sup\u003e. It should be noticed that the multiple terms in Equation (2) decide the stability of ferroelectric phases (T, O, or R) and barriers between different ferroelectric phases, the coefficients of these multiply terms will be zero when the system is at the triple point\u003csup\u003e71\u003c/sup\u003e. The global field effect can be described by the associated coefficients referred\u003csup\u003e72–78\u003c/sup\u003e. The terms \u003cem\u003ef\u003c/em\u003e\u003csub\u003eelas\u003c/sub\u003e, \u003cem\u003ef\u003c/em\u003e\u003csub\u003eelec\u003c/sub\u003e and \u003cem\u003ef\u003c/em\u003e\u003csub\u003egrad\u003c/sub\u003e in Equation(1) reflect the long-range elastic and electrostatic interaction energies and the short-range exchange interaction energy of gradient term respectively. The term \u003cem\u003ef\u003c/em\u003e\u003csub\u003eelec\u003c/sub\u003e =\u003cem\u003e\u0026nbsp;f\u003c/em\u003e\u003csub\u003edipole\u003c/sub\u003e +\u003cem\u003e\u0026nbsp;f\u003c/em\u003e\u003csub\u003edepola\u003c/sub\u003e +\u003cem\u003e\u0026nbsp;f\u003csub\u003eappl\u003c/sub\u003e\u0026nbsp;\u003c/em\u003e\u003csup\u003e79–81\u003c/sup\u003e, here \u003cem\u003ef\u003c/em\u003e\u003csub\u003edipole\u003c/sub\u003e is the dipole-dipole interaction caused by polarization, \u003cem\u003ef\u003c/em\u003e\u003csub\u003edepola\u003c/sub\u003e is the depolarization energy density and \u003cem\u003ef\u003csub\u003eappl\u003c/sub\u003e\u003c/em\u003e is the energy density caused by applied electric field. The term \u003cem\u003ef\u003csub\u003eLFE\u003c/sub\u003e\u003c/em\u003e represents the local field effect caused by doped defects, where a random number with different polarization directions have been considered in our simulation\u003csup\u003e79\u003c/sup\u003e. The temporal evolution of the spontaneous polarization field can be obtained by solving the time-dependent Ginzburg-Landau (TDGL) function as Equation (3):\u003c/p\u003e\n\u003cp\u003e\u003cimg src=\"data:image/png;base64,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\" width=\"212\" height=\"41\"\u003e\u003c/p\u003e\n\u003cp\u003eThe domain structure is described by a distribution of spontaneous polarization \u003cem\u003eP\u003c/em\u003e= (\u003cem\u003eP\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e, \u003cem\u003eP\u003c/em\u003e\u003csub\u003e2\u003c/sub\u003e, \u003cem\u003eP\u003c/em\u003e\u003csub\u003e3\u003c/sub\u003e). Further mathematical transformation was employed to obtain the symmetry contours from the calculated vector maps.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eDeclaration of Competing Interest\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u0026nbsp;\u003c/strong\u003eY. Liu and J. Xu contributed equally to this work.\u0026nbsp;The authors are thankful for the kindly help on synchrotron XRD measurements from Xingmin Zhang in Shanghai Synchrotron Radiation Facility. The authors acknowledge the help on experiments of TEM from Andong Xiao, the help on experiments of sample preparation from Siyan Yu and the help on PFM from Tianzi Yang and Guanqi Wang. J. Gao acknowledges the Fundamental Research Funds for the Central Universities of China (xtr042019002) and\u0026nbsp;the Natural Science Foundation of Ordos (2021EEDSCXQDFZ014) for financial support. Y. Liu\u0026nbsp;acknowledges the National Natural Science Foundation of China (Grant No. 52207031) and the Fundamental Research Funds of Xian Jiaotong University (xzy012021022).\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003ePan, H. \u003cem\u003eet al.\u003c/em\u003e Ultrahigh energy storage in superparaelectric relaxor ferroelectrics. \u003cem\u003eScience\u003c/em\u003e \u003cstrong\u003e374\u003c/strong\u003e, 100\u0026ndash;104 (2021).\u003c/li\u003e\n\u003cli\u003eLi, Q. \u003cem\u003eet al.\u003c/em\u003e Flexible high-temperature dielectric materials from polymer nanocomposites. \u003cem\u003eNature\u003c/em\u003e \u003cstrong\u003e523\u003c/strong\u003e, 576\u0026ndash;579 (2015).\u003c/li\u003e\n\u003cli\u003eLi, J. \u003cem\u003eet al.\u003c/em\u003e Grain-orientation-engineered multilayer ceramic capacitors for energy storage applications. \u003cem\u003eNat. 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This issue renders many otherwise promising dielectric energy storage materials unusable because significant temperature rise of the energy storage devices is inevitable during their service and some applications are in high temperature environment. The challenge at high temperatures arises from the physical inevitability of vanishing ferroelectric domains that lead to drop in polarization, and exponentially increased charge transport activity which leads to charge leakage and electrical breakdown. Here we report a material strategy to meet this challenge by designing a self-organized nanocomposite (1-x)(Ba,Sr)(Ti,Sn)O\u003csub\u003e3\u003c/sub\u003e-xBi\u003csub\u003e1.5\u003c/sub\u003eZnNb\u003csub\u003e1.5\u003c/sub\u003eO\u003csub\u003e7\u003c/sub\u003e composed of nano-sized antiferroelectric particles embedded into a trirelaxor matrix through a nanoscale phase separation process. At the optimal composition of x=0.11, the antiferroelectric-trirelaxor nanocomposite ceramic exhibits an outstanding energy storage performance from room temperature (energy density=8.5 J/cm\u003csup\u003e3\u003c/sup\u003e, efficiency=94.8% and a high figure of merit of 167 J/cm\u003csup\u003e3\u003c/sup\u003e) up to a high temperature of 200°C (energy density ~4.85 J/cm\u003csup\u003e3\u003c/sup\u003e, efficiency\u0026gt;90% and figure of merit of 49 J/cm\u003csup\u003e3\u003c/sup\u003e), which outperforms existing Pb-free dielectric materials. High-resolution transmission electron microscopy (TEM) and synchrotron x-ray diffractometry reveal that the coherent nanometric antiferroelectric particles and the trirelaxor nanodomains sustain over a wide temperature range. In-situ piezoresponse force microscopy (PFM) observation and phase-field simulations show that the nearly hysteresis-free switching of trirelaxor nanodomains is responsible for enhanced polarization (and hence energy density) and low hysteretic loss. Resistivity shows a 2~3 order of magnitude increase in electrical resistivity accompanying significant increase in breakdown strength up to high temperatures. Thermally stimulated depolarization current (TSDC) measurements suggest that the suppression of charge transport or leakage up to high temperature stems from charge trapping effect at high-density nanointerfaces between antiferroelectric and trirelaxor phases. These favorable effects in the nano-composite are responsible for its high energy storage performance up to high temperatures. Our research may provide a generic approach to achieving advanced dielectrics with outstanding performance at high temperatures.\u003c/p\u003e","manuscriptTitle":"Superior Energy Storage Performance up to 200°C in a Self-organized Trirelaxor-antiferroelectric Nanocomposite","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-02-19 18:25:14","doi":"10.21203/rs.3.rs-3926354/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"6f7400c1-2a7f-408a-9e7c-b14b154346de","owner":[],"postedDate":"February 19th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":28605130,"name":"Physical sciences/Materials science/Nanoscale materials/Nanoparticles"},{"id":28605131,"name":"Physical sciences/Energy science and technology/Energy storage/Supercapacitors"}],"tags":[],"updatedAt":"2025-01-23T14:36:26+00:00","versionOfRecord":[],"versionCreatedAt":"2024-02-19 18:25:14","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-3926354","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-3926354","identity":"rs-3926354","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}