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• Enhance FeN 4 active sites using tunable curved surfaces from mesoporous MOFs. • Show higher activity of lc-Fe-N 4 on low-curvature surfaces. • Exceptional ORR catalytic activity and stability in acidic electrolytes (0.82 V vs. RHE), comparable to commercial Pt/C. • Boost FeN 4 catalyst activity, unlocking the potential for broader electrocatalysis and energy storage applications. Iron-based single-atom catalysts (Fe-SACs) containing Fe–N 4 active sites have shown immense potential in the oxygen reduction reaction (ORR). However, the limited ability to adsorb O 2 and catalyze subsequent O–O bond breaking on Fe–N 4 sites has hindered their full potential, especially in acidic electrolytes. Here, we present an approach by utilizing a tunable curved surface to enhance the activity of Fe–N 4 active sites, with theoretical calculations, demonstrating that Fe–N 4 sites anchored on low–curvature surfaces (lc-Fe-N 4) is favirable for ORR. Experimental results show that the catalyst exhibits excellent catalytic activity and stability for ORR in acidic electrolytes, with a half-wave potential of 0.82 V vs. RHE, approaching that of commercial Pt/C. This work develops an approach for promoting the catalytic activity by anchoring atomically dispersed Fe–N 4 sites, unlocking their potential for extended use in electrocatalytic and energy storage applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • A facile-oriented self-assembly for synthesizing 2D-on-3D CoNi-LDHs nanoflowers. • The unique 2D-on-3D structure manifests excellent energy-storage performance. • The formation mechanism was oriented to self-assembly and Ostwald ripening. Layered double hydroxides (LDHs) have been the subject of increasing research due to their unique 2D or 3D structures and promising applications. However, achieving precise control over their morphology and architecture has proven to be a significant challenge. In this work, we present an oriented self-assembly strategy for the synthesis of ultrathin 2D-on-3D CoNi-LDHs nanoflowers (NFs) at ambient temperature. Ex situ and in situ characterization techniques were employed to elucidate the formation process of the 2D-on-3D CoNi-LDHs hierarchical structure. The 2D nanosheets are composed of CoNi(OH) 2 seeds that undergo rapid nucleation and growth. Under the influence of oriented attachment and Ostwald ripening, the 2D nanosheets continue to crystallize along the axial and radial directions, resulting in the formation of 2D-on-3D CoNi-LDH NFs. This unique 2D-on-3D LDHs structure possesses an ultrathin thickness of approximately 1.5 nm, nanopores with a diameter of approximately 3.8 nm, and a large surface area of approximately 154 m2/g. These properties manifest excellent energy-storage performance in supercapacitors. Our approach provides important insights into the precise synthesis of LDHs with a 2D-on-3D hierarchical structure. The synthesis of LDHs with well-defined structures is a significant challenge in materials science. Our work contributes to the advancement of this field and has the potential to facilitate the development of new, high-performance energy-storage devices. [ABSTRACT FROM AUTHOR]

• Engineering crystal growth and surface modification regulate the electron/ion transport behavior in anatase TiO 2. • Pseudocapacitive behavior are essential for fast charging with p-TiO 2 @NC anode. • Three-in-one strategy on TiO 2 surfaces enables robust interface chemistry. • Revealing sodium battery gas generation for safer practical applications. Sodium-ion batteries are a potential candidate for next-generation energy storage devices. Unfortunately, developing an anode with improved long-term cycling stability and high-rate performance remains a substantial problem. In this work, we develop that the Na+ intercalation pseudocapacitance in faceted titanium dioxide endows extreme fast charging and long cycle life in a sodium-ion battery. Theoretical calculations and comprehensive characterization exhibit that high ionic conductivity, stable solid electrolyte interphase (SEI), and pseudocapacitive behavior are essential for fast charging. This well-designed electrode demonstrates a significantly high reversible capacity of about 135 mAh g−1 at 90 C (∼30 A g−1) for 10,000 cycles with an 87.8% retension. Coupled with a vanadium phosphate sodium Na 3 V 2 (PO 4) 3 cathode, and this full cell displays a specific capacity of 310 mAh g−1 at 0.2 A g−1 for 100 cycles. This study unveils the key mechanisms for fast-charging sodium storage, and can also facilitate the improvement of other titanium-based anodes secondary batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amorphous/crystalline H-NiMoS 4 /NiS 2 hollow sphere was successfully constructed. • A high specific capacitance and good cycling performance was obtained. • The capacity retention of HSC was 83.7% after 20,000 cycles. • The HSC displayed a high energy density of 38.6 Wh kg−1 at 958.6 W kg−1. Phase engineering offers a promising strategy to tailor the physiochemical properties to further improve their electrochemical performance toward energy storage. However, it remains a challenge to fabricate well-defined amorphous/crystalline hetero-phase metal sulfides with high-density heterointerfaces. Herein, the synthesis of hetero-phase combination of amorphous NiMoS 4 and crystalline NiS 2 that possesses hollow nanosphere structure decorated by nanosheets (named as H-NiMoS 4 /NiS 2) is reported. Benefiting from the construction of the hollow nanosphere coated by nanosheets, amorphous/crystalline hetero-phase junction, and strong Ni-S hybridization, H-NiMoS 4 /NiS 2 electrode exhibits high specific capacity, outstanding rate capability and excellent cycling stability. Moreover, an all-solid-state supercapacitor was assembled with H-NiMoS 4 /NiS 2 as cathode and needle coke oxide (NCO) as anode, which can achieve remarkably high energy density of 38.6 Wh kg−1 at a power density of 958.6 W kg−1 and outstanding capacity retention of 83.7% after 20,000 cycling. The preparation of novel H-NiMoS 4 /NiS 2 nanomaterial with a hetero-phase of amorphous and crystalline provides a new solution for improving the structural stability and capacitor storage performance as electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]

• NiCo 2 O 4 nanoparticles with different morphologies were prepared via template method and self-assembly method. • The NiCo 2 O 4 nanoparticles were in-situ decorated onto porous carbon (PC) and used as host of sulfur cathode for lithium sulfur battery. • The synergistic effect of physical binding of PC and adsorption catalysis of NiCo 2 O 4 nanoparticles could effectively improve the performance of lithium sulfur battery. Lithium-sulfur battery (LSB) is one of the most appealing candidates for advanced next-generation electrochemical energy storage systems based on the merits of extraordinary theoretical specific energy density, abundant resources and environmental friendliness of sulfur. However, the "shuttle effect" of lithium polysulfides (LiPSs) and low utilization of sulfur cathode severely plague the large-scale commercialization of the LSBs. In this work, a novel host material for sulfur cathode, namely porous carbon (PC) decorated with NiCo 2 O 4 nanoparticles (NiCo 2 O 4 /PC), was designed and prepared. Among all tested NiCo 2 O 4 nanoparticles with different morphologies, the NiCo 2 O 4 nanoparticles with honeycomb pore shape (C-NiCo 2 O 4) showed excellent performance as sulfur cathode host. Benefiting from the synergistic advantages between PC and C-NiCo 2 O 4 nanoparticles, the C-NiCo 2 O 4 /PC host materials showed strong adsorption for LiPSs, promising the alleviation of shuttle effect and promoting the catalytic conversion process of LiPSs. As a result, the LSBs with S@C-NiCo 2 O 4 /PC cathode delivered a high specific capacity of 1065.2 mAh g−1 at 0.1C, a stable cycling over 500 cycles with low fading rate of 0.053% per cycle at 0.5C and an enhanced rate capability compared with those of S@C-NiCo 2 O 4 and S@PC cathodes. This work demonstrated the synergistic effect of physical shackle from PC and adsorption-catalysis from NiCo 2 O 4 nanoparticles, which might provide new insights into the optimization of carbonaceous architecture for rationally regulating the polysulfide redox reactions. [ABSTRACT FROM AUTHOR]

• Microwave-enabled one-pot synthesis of PW/EG composite for thermal energy storage. • Reducing preparation time from hours to a few minutes. • Outstanding stability and no leakage at 92% paraffin loading. • 16X enhancement of thermal conductivity, and nearly 100% capacity retention. • Integrating into thermoelectrics with 5X performant enhancement. To mitigate the intermittency of renewable energy generation and achieve net-zero greenhouse gas emissions, a cyclically stable and energy-efficient thermal energy storage system (TESS) is increasingly required. To prevent leakage and enhance thermal conductivity and stability, TESS is typically fabricated by impregnating energy storage materials (ESMs) into porous conductive additives. However, the impregnation-based encapsulation process is both time-consuming (several to tens of hours) and energy-intensive, and the incorporation of additives reduces the proportion of ESMs, resulting in decreased energy capacity. In this study, we present an ultrafast (several minutes) and energy-efficient one-pot encapsulation method for in situ encapsulation of paraffin wax (PW) within the pores of expanded graphite (EG) via microwave irradiation of expandable graphite (Eg) in molten PW. The resulting binary PW/EG composites exhibit shape stability and no leakage even at 92 wt% PW loading. The PW/EG composite with 10 wt% EG demonstrates a thermal conductivity of 3.7 W/mK (16.2 times higher than that of pure PW), a thermal release/absorption efficiency of around 99.5 %, and almost 100 % capacity retention after thermal cycling. Additionally, we demonstrate that integrating PW/EG TESS with thermoelectric (TE) modules can increase TE power generation by more than fivefold, highlighting their potential for energy storage and conversion as well as mitigating waste heat source intermittency. [ABSTRACT FROM AUTHOR]

A simple one-step reaction method is applied to produce a [Cu(NH 3) 2 ]Cl@3D CuZn current collector. During Li plating, the lithiophilic [Cu(NH 3) 2 ]Cl guides Li deposition into the pores and tunnels of the 3D framework, which can accommodate and limit volume expansion. These multiple effects enable low-barrier and dendrite-free Li plating/stripping with a stable and high electrochemical performance. [Display omitted] • Energy-efficient preparation method of [Cu(NH 3) 2 ]Cl@3D CuZn was developed. • Synergistic effects from three-dimensional structure and surface chelate enable good cycle stability. • Formation mechanism of the chelate compound on the 3D CuZn is revealed. • Coulomb efficiency of the [Cu(NH 3) 2 ]Cl@3D CuZn||Li half-cell stabilized for 270 cycles at 0.5C. • Li@[Cu(NH 3) 2 ]Cl@3D CuZn||Li symmetric-cell stabilized for 1200 h at 0.5C. Li-metal batteries (LMBs) are regarded as some of the most promising energy storage systems owing to their superior theoretical specific capacity and lowest electrochemical potential. However, the application of LMBs has been severely hindered by the uncontrollable dendrite growth and volume expansion of metal anodes during Li plating. Herein, we construct a three-dimensional (3D) porous CuZn current collector decorated with a lithiophilic [Cu(NH 3) 2 ]Cl compound (3D 1H3N), in which [Cu(NH 3) 2 ]Cl offers nucleation sites and guides fast Li+ deposition in the pores and tunnels. The 3D framework accommodates volume expansion and disperses deposition current. Together, these two functions contribute to low-barrier and dendrite-free Li plating/stripping with enhanced Coulombic efficiency (CE) and excellent stability. The half-cell utilizing the as-fabricated 3D 1H3N current collector exhibited a CE of 98 % for over 270 cycles at 0.5 mA·cm–2 and 97 % for over 220 cycles at 1 mA·cm–2. The Li@3D 1H3N anode stabilized over 270 cycles (1100 h) at 0.5C in symmetric cells and delivered a capacity retention of 92.5 % after 450 cycles at 1C (1C = 170 mAh·g–1) in full cells. This study sheds light on the multifunction modification of self-supported anode current collectors for advanced LMBs to promote their practical application. [ABSTRACT FROM AUTHOR]

• Fabrication of high-performance wafer-scale micro-supercapacitors with fractal structures. • Fractal design enhances electric field distribution and boosts capacitance in MSCs. • FMSCs achieve impressive specific capacitance of 615.3 μF cm−2 at 1 V s−1. • FMSCs exhibit superior high-frequency performance, ideal for kHz applications. • Effective high-frequency AC filtering demonstrated in an AC line filter circuit. Microsupercapacitors (MSCs) are attracting attention as vital filter capacitors for microscale power conversion in alternating current (AC) line-filtering circuits due to their rapid frequency response characteristics. This study demonstrates the wafer-scale fabrication of Ti 3 C 2 T x MXene-based MSCs with a high-potential device structure incorporating fractal microelectrodes. The experimental and simulation results show that the new structure enables increased ion-transport rates through increased absorption sites and a strong electric field, resulting in improved energy storage and frequency response performance. Therefore, by optimizing the size of the microelectrodes, the fractal MSCs (FMSCs) achieve a high specific capacitance of 615.3 μF cm−2 at 1 V s−1 and their highest frequency characteristic (f 0) can reach kHz. Notably, the FMSCs exhibit excellent filtering performance in AC line-filtering circuits by successfully filtering different AC waveforms at a high frequency of 20 kHz into direct current. [ABSTRACT FROM AUTHOR]

• SbBi x nanoparticles embedded in ultra-thin carbon networks are designed. • SbBi x @C exhibits excellent performance in both sodium and potassium storage. • The influence of proportion in SbBi x on energy storage behavior is revealed. • SEI composition and particle surface states play an important role in energy storage. The alloy proportions of SbBi x show obvious influence on sodium/potassium storage. Herein, SbBi x nanoparticles embedded in ultra-thin carbon networks (SbBi x @C, x = 1, 0.5, 0.15) are successfully synthesized by a facile salt template assisted pyrolysis method. The effect of different alloy proportions on the chemical and electrochemical properties of active materials is revealed. Density functional theory calculation demonstrates that SbBi 0.5 has the smallest formation energy (−5.131 eV) and the smallest volume expansion rate for both sodium/potassium storage (222%/376%). Benefiting from the optimized volume expansion for both sodium/potassium storage and carbon networks structure, the optimized SbBi 0.5 @C anode shows high reversible capacities of 301 mAh/g and 390 mAh/g after 100 cycles at 0.1 A/g for sodium/potassium storage, respectively. It is also observed that the SbBi 0.5 @C anode delivers different behaviours of sodium/potassium storage, which is due to the various composition of SEI films formed after sodium/potassium storage. It is believed that this work provides a synthetic strategy for fabricating alloy-type anode materials for SIBs/PIBs, in view of structure design and the regulation of alloy proportion. [ABSTRACT FROM AUTHOR]

• The hierarchical M-ZCOH/NPG/NF heterostructures were successfully constructed. • The BIEF in the heterointerface enhanced electronic/ionic transport dynamics. • A high capacity reaching ∼1247.1C g−1 (∼2771.3 F g−1) at 1 A g−1 was obtained. • The HSC displayed ultrahigh energy density of ∼78.3 Wh kg−1 at ∼800 W kg−1. The superior electronic/ionic transport dynamics of electrode materials have been crucial to achieve appealing high performance for supercapacitors. Herein, a fascinating one-dimensional (1D) zinc cobalt hydroxide nanobelts/0D irregular manganese dioxide nanoparticles (M-ZCOH) have been vertically loaded into the 3D Ni foam (NF) substrate wrapped by nitrogen-doped graphene (NPG) (M-ZCOH/NPG/NF) for supercapacitors. The ingeniously designed M-ZCOH/NPG/NF composites feature powerful built-in electric field (BIEF) introduced by well-defined heterointerface with abundant oxygen vacancies defects. The formed electron accumulation triggering strong interfacial interaction verified by the differential charge density analysis may endow M-ZCOH/NPG/NF with the extra driving force to increase the diffusion/adsorption of electrolyte ions, thereby facilitating electron/ion transfer kinetics. Also, the qualitative negative shift of the d band center for M-ZCOH composites further evidences a lower electron/ion transfer barrier compared with the monomers. Obviously, the penetrating understanding of heterointerface on the improved properties is manifestly interpreted by combining theoretical and experimental analysis. Moreover, the ingenious strategy of engineering the heterointerfaces in unique heterostructure with rich defects may provide a new prospect for optimizing other advanced materials in sustainable energy storage systems. [ABSTRACT FROM AUTHOR]

Lithiophilic COF@PP separator (TpPa-SO 3 H@PP) was prepared through the strategy combining with in-situ interfacial polymerization reducing the interfacial resistance and lithiophilic groups engineering which can suppress the shuttle effect and facilitate Li+ migration, and it exhibits superior performances. [Display omitted] • In situ interfacial synthesis promotes on preparing COF or POP modified PP separator. • Lithiophilic groups prominently facilitate Li+ transport and suppress shuttle effect. • Batteries with modified separators exhibit superior electrochemical performances. Lithium–sulfur batteries have been considered one of the most promising energy storage devices because of their high energy density (2600 W·h·kg−1), low cost, and the environmental friendliness of sulfur. However, the shuttle effect caused by the soluble polysulfide produced by the sulfur cathode in the redox process seriously affects the commercialization of the battery. To solve such problems, we designed and synthesized a lightweight covalent organic framework (COF)–based TpPa–SO 3 H@PP separator through in situ interfacial polymerization. Benefiting from the lithiophilic –SO 3 H groups, which are arranged in the nanochannels of the TpPa–SO 3 H COF, the TpPa–SO 3 H@PP separator not only suppresses the shuttle of polysulfide but also facilitates Li+ migration. Moreover, the good wettability of the electrolyte to the TpPa–SO 3 H@PP separator resulted in a lower interfacial resistance and higher ionic conductivity, ensuring a higher energy density. Based on the above advantages, cells with the TpPa–SO 3 H@PP separator showed an initial specific capacity of 863.97 mAh g−1 at 1C, and a capacity of 645.62 mAh g−1 after 500 cycles, and the average capacity decay rate of each cycle was only 0.05%, indicating superior cycling performance. Significantly, we extended the in situ interfacial polymerization to the preparation of a lithiophilic amorphous porous organic polymer (POP)–based TpPa–COOH@PP separator, which also has good performance, demonstrating the universality and effectiveness of in situ interfacial polymerization. This work opens a new route to prepare lithiophilic COF@PP and POP@PP separators with a lower shuttle effect and higher ion transport via in situ interfacial polymerization for high–performance Li–S batteries. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fly ash-based transition metal silicate is prepared by a synergistic strategy. • The crystalline SiO 2 of fly ash turns into Ca 2 SiO 4 with high-temperature roasting. • The uniformly dispersed carbon nanofibers cover surface by electrostatic assembly. • The heterostructure and S doping enhance the internal conductivity of material. • The composite shows a high specific capacitance of 493.33 F·g−1 at 0.5 A·g−1. Based on the high-calcium fly ash of an actual coal-fired power plant, the crystalline silica is successfully transformed into cobalt-iron silicate, and then CNFs/FA-CoFeSiSx with good energy storage performance is obtained by modifying the cobalt-iron silicate as the electrode material of supercapacitor. The crystalline silica is successfully converted to silicate (Ca 2 SiO 4) by high-temperature calcination with NaHCO 3 and fly ash. Meanwhile, a 3D porous structure of fly ash is obtained by etching. Ion exchange is successfully carried out by the one-step hydrothermal method, which realizes the transition of Ca 2 SiO 4 to Co 2 SiO 4 and Fe 2 SiO 4. The further modification through electrostatic self-assembly and sulfurization process significantly increases the electron migration rates. The situation that fly ash is difficult to be used in energy storage is ameliorated by the coordinated regulation of various strategies. The final product CNFs/FA-CoFeSiSx exhibited a high specific capacitance (493.33 F·g−1 at 0.5 A·g−1), high Coulombic efficiency (about 100% at 10 A·g−1), and good cycle performance (79.50% capacitance retention after 1800 cycles). Finally, a solid-state asymmetric supercapacitor is assembled based on CNFs/FA-CoFeSiSx as the positive electrode and commercial active carbon as the negative electrode, which performs the maximum energy density of 25.43 Wh·kg−1 and power density of 359.07 W·kg−1. Considering the good energy storage characteristics of fly ash electrode materials, this work provides a low-cost preparation method for electrochemical energy storage and realizes the high-value utilization of fly ash. [ABSTRACT FROM AUTHOR]

[Display omitted] • A nitrilotriacetic acid-assisted strategy for controllable synthesis of NiS/carbon hexahedrons was proposed. • Synchronous realization of the combination of carbon with NiS and morphology controlled in one step. • Formation mechanism and determinants of NiS/carbon composites are revealed. • Enhanced power density (4187.2 W kg−1) and energy density (30.8 Wh kg−1). Effective adjustment of structure and morphology is considered to be an available strategy to improve the energy storage performance of supercapacitor electrode materials. Herein, a series of hierarchical NiS/carbon hexahedrons consist of self-assembling nanoplates or nanorods were synthesized via nitrilotriacetic acid (NTA)-assisted hydrothermal strategy. This study demonstrates that the micro-morphology of the unit structure constituting the hexahedrons can be controlled by adjusting the concentration of NTA. Benefiting from synergetic effect of high void space, hierarchical assembly mode and integrated composite structure, NiS/carbon hexahedrons promote adequate exposure of abundant active sites and enhance the structural stability, donating superior energy storage performance. As expected, the optimized NiS/carbon electrode (NiS/NTA-2) exhibits superb capacitive performance, including excellent specific capacitance of 1530.4 F g−1 at 1.0 A g−1 and remarkable cycle stability with 85.6% after 5000 cycles. Employing the as-prepared NiS/NTA-2 composites as positive electrode, the hybrid supercapacitor device with spectacular capacity of maximum energy density and power density up to 35.1 Wh kg−1 and 4509.3 W kg−1 and impressive long-term stability of 87.2% retention after 5000 cycles is assembled. Moreover, a light-emitting diode (LED) is successfully illuminated for up to 12 min by two devices connected in series. Based on this strategy, high-performance energy storage devices can be further developed through utilizing the modulation effect of metal complexes to design morphology controlled electrode materials. [ABSTRACT FROM AUTHOR]

• The doping of SSN increased the band gap width and decreased the grain size. • The ceramic possesses an energy density of 4.42 J/cm3 and an efficiency of 60%. • The transmittance of the ceramic is 76.7% and 84.5% at 780 and 1378 nm, respectively. • 0.825KNN-0.175SSN ceramic exhibited a small strain effect of 0.022%. Lead-free transparent ferroelectric ceramics with superior energy storage properties are highly desirable for pulsed power technologies and the increased optical transparency demand. However, the transparency and energy storage density of lead-free bulk ceramics cannot meet the requirements of their wide applications due to the coarse microstructure and relatively low breakdown strength. In this study, a design strategy is proposed to optimize the energy storage characteristics and transparency of ceramics by introducing nanodomains, increasing the band gap energy and reducing the grain size. The results showed that submicron grain (0.21 μm) and large band gap energy (E g = 3.21 eV) were achieved through the introduction of the second component Sr(Sc 0.5 Nb 0.5)O 3 (SSN). An excellent transparency of up to 84.5% in the near-infrared region (1378 nm), a high energy density (W) of ~4.42 J·cm−3 and an extremely small strain of ~0.022% were simultaneously achieved in the 0.825(K 0.5 Na 0.5)NbO 3 -0.175Sr(Sc 0.5 Nb 0.5)O 3 (0.825KNN-0.175SSN) ceramics. These results revealed the potential applications of (K 0.5 Na 0.5)NbO 3 -based ceramics for energy storage and provide a feasible approach of domain engineering to develop new lead-free energy storage transparency materials. [ABSTRACT FROM AUTHOR]

• An ultrahigh W rec of 5.4 J/cm3 and a relatively high η of 66% were achieved. • Wide E g and suppression of oxygen vacancy result in an improved E b. • Good thermal stability with W rec and η over a wide temperature range. Lead-free silver niobate (AgNbO 3 , AN)-based dielectric ceramics have attracted intense attention for high-power energy storage applications since 2016 due to their electric-field-assisted antiferroelectric-ferroelectric phase transition. In this work, chemical compositions of 0.2 wt.% Mn-doped (1- x)AgNbO 3 - x Ca(Hf 0.2 Ti 0.8)O 3 (AN-CHT x , x = 0.00–0.08) were designed and their ceramic samples were prepared in flowing oxygen via solid-state route. Our results show that the CHT modification not only enhance the antiferroelectricity stability but also the breakdown field (E b). Further investigation reveals that the wider band gap (E g) and suppression of oxygen vacancy play more important role in increasing E b of AN-CHT x ceramics. Consequently, an ultrahigh recoverable energy density (W rec) of 5.4 J/cm3 together with a relatively high energy conversion efficiency (η) of 66% is achieved under an electric field of 300 kV/cm in AN-CHT0.06 ceramics. Meanwhile, this ceramic also exhibits a good thermal stability with W rec (4.5 J/cm3) and η (69%) over a wide temperature range (25–120 °C) under external electric field of 280 kV/cm. The finding in present work indicates that modulating the band structure and oxygen vacancy of AN-based ceramics may lead to the discovery of new antiferroelectric materials with pronounced energy storage properties. [ABSTRACT FROM AUTHOR]

• BMN modified BCZT exhibits higher polarization and breakdown strength. • 0.925BCZT-0.025BMN ceramic possesses a high energy density and efficiency. • Excellent temperature and frequency stability of energy density have been achieved. • Domain engineering on the nanoscale was designed and observed in the ceramics. The improvement of energy density and efficiency is currently the main challenge in the application of lead-free dielectric energy-storage materials. Relaxor ferroelectric ceramics are the most commonly selected materials for pulsed power capacitors because of their inherent advantages, such as ultra-high power density, fast charging/discharging, and long lifetime. In this study, BiMg 2/3 Nb 1/3 O 3 (BMN) was doped to enhance energy density and efficiency in the (1− x)Ba 0.85 Ca 0.15 Zr 0.1 Ti 0.9 O 3 - x BiMg 2/3 Nb 1/3 O 3 systems based on the adjusted breakdown strength and polarization. As a result, a giant recoverable energy density of 3.81 J/cm3 and a high energy efficiency of 90.5% were simultaneously achieved in the 0.925BCZT-0.075BMN ceramic, which the energy density is 26 times as large as that of BCZT ceramic. Excellent temperature (−25 to 100 °C) and frequency (1–100 Hz) stability of recoverable energy density and energy efficiency were confirmed with the fluctuations below 4.5%. Domain engineering on the nanoscale was designed in relaxor ferroelectrics, which effectively improved the energy storage performance. Our study provides a feasible guideline to develop lead-free ceramics for electrical energy storage applications. [ABSTRACT FROM AUTHOR]