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The present study aims to improve the mechanical, thermal and dielectric properties of polyetherimide (PEI) nanocomposite via simplified method, involving the creation of a nanocomposite using PEI incorporated with exfoliated‐chemical functionalization induced hexagonal boron nitride nanosheets (BNNS). XRD, FTIR and Raman elucidated the chemical structure of functionalized BNNS and indicated the success preparation of functionalized BNNS. Functionalization effectively improved the compatibility of nanocomposites and contributed to the property improvements. Morphological analysis unveiled a compact and dense microstructure within the nanocomposites in correlation with functionalized BNNS. Broad band dielectric spectroscopy revealed excellent dielectric properties of produced PEI nanocomposite. DMA testing verified a noteworthy enhancement in both Tg and storage modulus upon incorporating of BNNS. In summary, this comprehensive investigation highlights the impact of functionalized BNNS on mechanical, thermal and dielectric properties of developed PEI dielectric nanocomposite and is expected to expand the application of PEI in the field of high‐temperature energy storage. Highlights: Polyetherimide (PEI) was used as polymer matrix and boron nitride derivatives as dielectric fillers to prepare PEI dielectric nanocomposite.Due to the influences of dielectric properties by interface polarization effect and the local distribution of electric field of the fillers in PEI matrix, the dielectric constant, breakdown strength and energy storage density of PEI nanocomposites were obviously improved compared with pure PEI.The effects of interfacial interactions between PBNNS and PEI contributes to the uniform dispersion and comprehensive property improvements of PEI dielectric nanocomposites.This work presents a systematic investigation into the fabrication of PEI/BNNS nanocomposite using a one‐step solution blending method, inspiring the research and development of PEI in the energy storage applications areas in the future. [ABSTRACT FROM AUTHOR]

The rational structural design and compositional merits as well as the synergistic coupling effect can break the properties of single material and broaden the microwave absorption band. Herein, the unique lightweight Fe-doped MnO 2 @C hollow nanocubes are rationally designed and successfully synthesized via a scalable wet chemical process and polydopamine coating followed by high-temperature calcination. By virtue of the unique structure and compositional merits, the as-obtained Fe-doped MnO 2 @C hollow nanocubes (Fe–MnO 2 @C-HNBs) displayed notable microwave absorption performance (MAP), simultaneously achieving ultra-broad absorption bandwidth and strong absorption characteristics at a low thickness of 2.3 mm (the reflection loss of −41.02 dB and the effective absorption bandwidth of 5.86 GHz). Surprisingly, the effective absorption bandwidth (RL < −10 dB) could reach up to 8.08 GHz and the minimum reflection loss (RLmin) was −38.20 dB at the thickness of 2.7 mm. The results further confirmed that the excellent microwave attenuation ability of the as-prepared Fe–MnO 2 @C-HNBs composites benefitted from the special "air@core-shell" structure and multiple heterointerfaces as well as multi-component recombination. These results demonstrated that the as-obtained Fe–MnO 2 @C-HNBs composites could be attractive candidates for broadband microwave absorption materials. [ABSTRACT FROM AUTHOR]

1D magnetic fibers with significant morphological diversity and magnetic anisotropy are highly desirable for optimizing magnetic properties and electromagnetic responsiveness. However, it remains challenging for the precise control over internal magnetic interactions within each fiber. Herein, a strategy for self‐assembled magnetic coupling is taken to achieve the controllable reconstruction of continuous multiple coupling networks within a single fiber. High‐density ultrafine cobalt nanoparticles are uniformly embedded inside a carbon framework with a 1D multi‐channel structure (Co@MCF). This structure establishes a complex magnetic response system characterized by inherent inter‐fiber interactions and refined intra‐fiber self‐assembling coupling. The distinctive distribution of magnetic flux lines demonstrates enhanced magnetic sensitivity. This results in a minimum reflection loss of −57.65 dB and a broadband absorption frequency range of 7.28 GHz at 1.9 mm, effectively covers the entire Ku band and a substantial portion of the X band. The multi‐channel structure enhances the understanding of the relationship between microstructure and performance in magnetic fibers. Additionally, it positions Co@MCF as a highly competitive candidate for microwave absorption applications. [ABSTRACT FROM AUTHOR]

Heterostructure design has been recognized as a promising strategy to reinforce the dielectric polarization response through the strengthened heterogeneous interface interaction. However, the controllable preparation of homogeneously distributed heterostructures in absorbers remains a great challenge. Herein, we proposed a moderate reduction strategy to synthesize a NiO/Ni heterostructure tightly embedded in MoO3–x nanorods in situ by controlling phase evolution of NiO to metallic Ni under the H2/Ar atmosphere. Profiting from the abundant NiO/Ni heterostructures that induced electron migration and redistribution at NiO/Ni interfaces, the NiO/Ni/MoO3–x absorbers show a strengthened interfacial polarization relaxation response. Enriched oxygen vacancies serve as dipole polarization centers to form independent electric dipole pairs, which are conductive to the enhancement of dipole polarization loss under the alternating electromagnetic filed. Additionally, the homogeneously distributed magnetic Ni species construct a magnetic coupling network and generate ferromagnetic resonance and eddy current loss to boost magnetic loss. Consequently, the resultant absorbers display superior electromagnetic wave absorption performances with a minimum reflection loss value of −64.18 dB and maximum absorption bandwidth up to 6.6 GHz with a thickness of 1.8 mm, effectively covering the whole Ku-band. The radar cross-section (RCS) simulations demonstrate the excellent radar signal suppression capability of NiO/Ni/MoO3–x absorbers and the maximum RCS reduction value reaching 21.3 dB at 0°. The obtained absorption properties almost surpass most of the reported composites with embedded heterostructures. This work provides a strategy for the preparation of multiple heterogeneous interfaces and presents a deep insight into the attenuation mechanisms of absorbers. [ABSTRACT FROM AUTHOR]

Electrostatic capacitors with ultrahigh energy‐storage density are crucial for the miniaturization of pulsed power devices. A long‐standing challenge is developing dielectric materials that achieve ultrahigh recoverable energy density Wrec ≥ 10 J cm−3 under moderate electric fields (30 ≤ E ≤ 50 kV mm−1). Herein, a specific high‐entropy strategy is proposed to modulate the phase structure and interfacial polarization of medium‐entropy base materials using linear dielectrics. This strategy ensures a sufficient polar phase and a high enough electric field for complete polarization, thereby achieving ultrahigh Wrec by enhancing polarization strength. The validity of this strategy is demonstrated in the (Na0.282Bi0.282Ba0.036Sr0.28Nd0.08)TiO3‐xCa0.7Bi0.2TiO3 (NBBSNT‐xCBT) (x = 0–0.15) system. The CBT‐modulated samples exhibit a polyphase structure of R3c, P4bm, and Pm‐3m with reduced remnant polarization (Pr). Additionally, the addition of CBT effectively suppresses interfacial polarization, enhancing the maximum polarization (Pmax). These factors significantly improve the value of ∆P = Pmax − Pr. As a result, an ultrahigh Wrec of 10.5 J cm−3 with a high‐efficiency η of 80.3% is obtained in the x = 0.1 sample under a moderate electric field of 45 kV mm−1 for the first time. This work paves the way for achieving superior energy‐storage performance under moderate electric fields. [ABSTRACT FROM AUTHOR]

Hollow ceramic microspheres (HCMs) have widespread applications in aerospace and electronic areas owing to their multiple merits such as low density, low thermal conductivity, oxidation, and high‐temperature resistance. In this work, monodispersed HCMs were fabricated based on preceramic polymers and the pulse‐controlled coaxial injection approach. The size and shell morphology of hollow ceramic spheres can be flexibly tailored by adjusting the diameters of coaxial needles, and the composition and flow rates of inner and outer liquids. As‐obtained HCMs were comprised of ultrafine nanocrystals of ZrO2, SiO2, ZrC, and SiC, which can enhance the interfacial polarization effect. Through optimization of microstructure and composition, the electromagnetic shielding performance of HCMs reached up to 45 dB in the frequency range of 12–18 GHz. This work demonstrates a facile and general method for the fabrication of monodispersed HCMs. [ABSTRACT FROM AUTHOR]

The presence of core–shell nanowire diminishes the distribution distortion of local electric field and also obstructs the flow of charge carriers. Polymer composite with fibrous structure demonstrates the improved polarization, and this work sheds a light on the energy loss related to the interface of polymer film for application of next-generation dielectric capacitor. [Display omitted] The development of polymer film with large electrical displacement is essential for the applications of lightweight and compact energy storage. The dielectric diversity at interface of polymer composite should be addressed to realize the film capacitor with high energy density and dielectric reliability. In this work, poly(vinylidene fluoride- co -chlorotrifluoroethylene) (P(VDF-CTFE)) nanocomposite was incorporated by core–shell nanowire with covalent organic framework (COF) outer coating to alleviate the dielectric mismatch at interface. After the preparation of Ag nanowire through polyol reduction, polyaniline (PANI) and COF layers were sequentially deposited to construct core–shell Ag@polyaniline@covalent organic framework (Ag@PANI@COF) nanowire. According to the unique core–shell architecture, the COF framework is utilized to suppress the remanent polarization while high electrical displacement is preserved by the center Ag nanowire. The maximum energy density of 25.0 J/cm3 at 425 MV/m is obtained in 0.1 wt% stretched Ag@PANI@COF/P(VDF-CTFE) nanocomposite. The presence of core–shell nanowire depresses the distribution distortion of electric field and the diffusion of charge carriers under high field. This work demonstrates an effective method to develop the polymer film with large electrical displacement, and sheds a light on insightful exploration of interfacial polarized mechanism in polymer dielectric composite. [ABSTRACT FROM AUTHOR]

Nano‐heterointerface engineering has been demonstrated to influence interfacial polarization by expanding the interface surface area and constructing a built‐in electric field (BEF), thus regulating electromagnetic (EM) wave absorption. However, the dielectric‐responsive mechanism of the BEF needs further exploration to enhance the comprehensive understanding of interfacial polarization, particularly in terms of quantifying and optimizing the BEF strength. Herein, a “1D expanded 2D structure” carbon matrix is designed, and semiconductor ZnIn2S4 (ZIS) is introduced to construct a carbon/ZIS heterostructure. The cross‐dimensional nano‐heterointerface design increases interface coupling sites by expanding the interface surface area and induces an increase in the Fermi level difference on both sides of the interface to modulate the distribution of interface charges, thereby strengthening the BEF at the interface. The synergistic effect leads to excellent EM absorption performance (minimum reflection coefficient RCmin = −67.4 dB, effective absorption bandwidth EAB = 6.0 GHz) of carbon/ZIS heterostructure. This work introduces a general modification model for enhancing interfacial polarization and inspires the development of new strategies for EM functional materials with unique electronic behaviors through heterointerface engineering. [ABSTRACT FROM AUTHOR]

Three-dimensional network structures of flower-like 1T/2H Molybdenum disulfide nanosheets anchored to carbon fibers were prepared, which exhibited satisfactory electromagnetic wave absorption properties, providing a path for the preparation of electromagnetic wave absorbing materials with wide effective absorption bandwidth. [Display omitted] • 3D 1T/2H MoS 2 /CNFs interconnected network structures were prepared; • Heterogeneous interfaces between CNFs and MoS 2 , 1T and 2H MoS 2 phase was built; • Excellent EM wave absorption with RL min of −42.26 dB and EAB of 6.48 GHz was obtained; • The EM wave absorption performance was proved by radar reflectance cross section simulation. With the wide application of electromagnetic waves in national defense, communication, navigation and home appliances, the electromagnetic pollution problem is becoming more and more prominent. Therefore, high-performance, and low-density composite wave-absorbing materials have attracted much attention. In this paper, three-dimensional (3D) network structures of flower-like 1T/2H Molybdenum disulfide nanosheets anchored to carbon fibers (1T/2H MoS 2 /CNFs) were prepared by electrostatic spinning technique and calcination process. The morphology and electromagnetic wave absorption properties were tuned by changing the content of flower-like MoS 2. The optimized 1T/2H MoS 2 /CNFs composite exhibits superior electromagnetic wave absorption with minimum reflection (RL min) of −42.26 dB and effective absorption bandwidth (EAB) of 6.48 GHz at 2.5 mm. Multi-facts contribute to the super performance. First, the uniquely designed nanosheet and 3D interconnected networks leads to multiple reflection and scattering of electromagnetic waves, which promotes the attenuation of electromagnetic waves. Second, the propriate content of CNFs and MoS 2 with different phase regulates its impedance matching characteristic. Third, Numerous heterogeneous interfaces existed between CNFs and MoS 2 , 1T and 2H MoS 2 phase results in interface polarization. Besides, the 1T/2H MoS 2 rich in defects induces defect polarization, improving the dielectric loss. Furthermore, the electromagnetic wave absorption performance was proved via radar reflectance cross section simulation. This work illustrates 1T/2H MoS 2 /CNFs is a promising material for electromagnetic absorption with wide bandwidth, strong absorption, low density, and high thermal stability. [ABSTRACT FROM AUTHOR]

Antiferroelectric (AFE) ceramics can be used in pulse power devices for high power density and fast discharge. Composites are recognized as an effective strategy to combine the benefits of different materials but suffer from interfacial mismatch and interfacial polarization. In this work, a combination of high-breakdown Pb 0.94 La 0.04 (Zr 0.99-x Sn x Ti 0.01)O 3 (PLZST) with high-efficiency Pb 0.8925 Ba 0.04 La 0.045 (Zr 0.65 Sn 0.3 Ti 0.05)O 3 (PBLZST) is explored to enhance energy storage performance. Via adjusting Sn content in PLZST, the difference in lattice and dielectric properties between two phases are reduced, decreasing interfacial polarization. The breakdown strength of PBLZST-PLZST is boosted from 285 kV cm−1 to 345 kV cm−1, with maximum polarization strength decreasing from 44 μC cm−2 to 36 μC cm−2. An recoverable energy density (W re ∼ 7.152 J cm−3) and discharged efficiency (η ∼ 90.5%) has been achieved in Pb 0.8925 Ba 0.04 La 0.045 (Zr 0.65 Sn 0.3 Ti 0.05)O 3 -Pb 0.94 La 0.04 (Zr 0.69 Sn 0.3 Ti 0.01)O 3 (x = 0.3) composite ceramics. These findings highlight the potential of interfacial polarization engineering for developing composite ceramics with high-energy storage performance. • The strategic introduction of PLZST with high E b into PBLZST with high η boosts comprehensive energy storage performance. • Through variating the amount of Sn in the secondary phase, the difference in lattice and dielectric properties between the two phases is reduced. • Compatible interface and diminished interfacial polarization in composites are obtained. • The reduced interfacial polarization boosts the E b of PBLZST-PLZST. [ABSTRACT FROM AUTHOR]

[Display omitted] Flexible sensors and actuators are the basis for realizing the Internet of Everything. This study identifies specific interfacial polarization and filler dispersion challenges in flexible sensors. A novel sandwich-structured flexible sensor with polydimethylsiloxane (PDMS)-filled Nb 2 CT x as the interlayer and poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)]-filled barium titanate (BTO) as the upper and lower layers was designed and fabricated. The thickness of the interlayer was optimized to be 6.2 μm, resulting in an ultrahigh sensitivity of 16.05 V/N and ultrashort response time of 626 μs. The interlayer achieved an oriented arrangement of the dipoles in the upper and lower piezoelectric films through interfacial polarization, enhancing the piezoelectric output and sensitivity. The proposed mechanism was confirmed by the dielectric properties, local piezoelectric response, cross-sectional potential simulation, and interfacial electrical calculations. Additionally, the sensor effectively distinguishes various body movements, facial micro-expressions, and throat vibrations during vocalization, and can be applied to ultrahigh-sensitive self-powered flexible piezoelectric pressure sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] Electromagnetic (EM) pollution can disrupt the functioning of advanced electronic devices, hence it's necessary to design EM wave absorbers with high-level absorption capabilities. The Ti 3 C 2 T x (MXene) is classified as a potential EM absorbing material; nevertheless, the lack of magnetic loss mechanism leads to its inadequate EM absorbing performance. On this basis, a novel composite design with promising EM absorption properties is hypothesized to be the integration of few-layer MXene and heterogeneous magnetic MOF derivatives (Fe 3 O 4 /C) with complementary advantages. Herein, we synthesized two-dimensional (2D) interfacial-polarization-enhanced MXene hybrid (Fe 3 O 4 /C/MXene) by electrostatic assembly. It is notable that the interfacial polarization is realized by adding a small amount of magnetic Fe 3 O 4 /C. Furthermore, the Fe 3 O 4 /C/ MXene demonstrates an astonishing effective absorption bandwidth (EAB) of 10.7 GHz and an excellent EM wave absorption performance (RL min) of −66.9 dB. Moreover, the radar cross section (RCS) of Fe 3 O 4 /C/MXene is lower than −15.1 dB m2 from −90° to 90° with a minimum RCS value of −52.6 dB m2 at 32°. In addition, the significant attenuation of the EM wave is due to the synergistic effect of improved impedance matching, dielectric loss, and magnetic loss. Thus, the magnetized Fe 3 O 4 /C/MXene hybrid is expected to emerge as a strong contender for high-performance EM wave absorbers. [ABSTRACT FROM AUTHOR]

Core–shell structures are commonly employed in microwave absorption (MA) materials due to their distinctive interfacial architecture. In this study, ferroferric oxide@polypyrrole (Fe3O4@PPy) nanocomposites with hollow core–shell structures were successfully synthesized for MA using a solvothermal process, followed by in situ polymerization. The minimum reflection loss (RLmin) frequency of the nanocomposites can be precisely controlled by adjusting the thickness of the PPy shell. The thickening of the PPy shell enhances the conduction loss of the nanocomposites, thus, enhancing the dielectric loss of the nanocomposites. The fabricated FP-170, FP-180 and FP-190 nanocomposites exhibit remarkable MA properties at low frequencies, with their RLmin reaching −63.82 dB, −84.92 dB, and −71.25 dB at 4.55 mm, 3.87 mm, and 2.64 mm, respectively. The maximum effective absorption bandwidth (EABmax) of FP-170 extends to 3.48 GHz at 2.39 mm, FP-180 extends to 4.20 GHz at 2.38 mm, and FP-190 extends to 4.96 GHz at 2.16 mm. The FP-200 nanocomposite, which has PPy shell thickness of 15 nm, exhibits exceptional radar stealth performance, with Radar Cross-Section (RCS) values below −17.68 dB·m2 within the range of −90° to 90°. Both simulation and experimental results prove that the hollow core–shell structured Fe3O4@PPy nanocomposite is an excellent candidate for MA applications. [ABSTRACT FROM AUTHOR]

Three mutual weight ratios of corn starch powder and polyvinyl acetate PVA wood glue were created for biocomposite materials: 40% starch/60% PVA, 50% starch/50% PVA, and 60% starch/40% PVA. Studying their physical, mechanical, thermal, electrical, and structural characteristics allowed for the evaluation of these composite materials. At room temperature, the samples were manually mixed. The results showed a decrease in the values of the AC conductivity and the thermal conductivity with an increase in the percentage of starch up to 60%, whereas the mechanical properties of the samples that contained starch at a concentration of 60% increased. [ABSTRACT FROM AUTHOR]

Flexible piezoelectric pressure sensors (FPPS) received a lot of attention because of their prominent performance in body motion detection and energy recovery. However, it has faced a huge challenge in manufacturing FPPS with high sensitivity, low cost, and high flexibility. Herein, a ternary flexible nanofiber composite with Sb nanosheets and BaTiO3 nanoparticles as the fillers of P(VDF‐TrFE) is prepared by electrospinning. An impressive open‐circuit voltage of 17.1 V and short‐circuit current of 4.4 µA is obtained based on the composite nanofiber mat at a pressure of 128 kPa with 2 Hz frequency. The FPPS not only exhibit a high sensitivity of 96 mV kPa−1 but also an ultrafast response time of 2 ms. Excellent flexibility and reliability are demonstrated by the unchanged open‐circuit voltage after 2400 cycles. The enhanced FPPS performance is owed to the interfacial polarization effect at the inorganic filler‐organic matrix interface, which also enhances the ferroelectric and dielectric properties. The present FPPS is further confirmed to be a real‐time motion monitor and voice recognizer, which can distinguish various actions and sounds according to distinct output voltage signals and is expected to be used in virtual reality devices, robotic electronic skin, haptic simulation, artificial throat, etc. [ABSTRACT FROM AUTHOR]

This work investigates the enhancement of dielectric properties of La2NiO4-CuO terpolymer nanocomposites using surface modified SiC nanoparticles as fillers. SiC nanoparticles were subjected to acid treatment and annealing at 1000 °C to tailor the surface chemistry. Acid treatment involved immersing the SiC powder in a mixture of H2SO4 and HNO3 acids and sonicating for 30 min, followed by stirring at 60 °C for 6 h. Annealing was carried out at 1000 °C for 2 h in an inert argon atmosphere. La2NiO4 and CuO nanoparticles were synthesized by sol-gel and precipitation techniques respectively, with average particle sizes of 20–40 nm and 10–15 nm confirmed by XRD and FESEM. Nanocomposites were fabricated by dispersing 2–10 wt% of untreated, acid treated and annealed SiC nanoparticles in a La2NiO4-CuO mixture solution, using PVDF as the polymer matrix. Impedance spectroscopy revealed that addition of 5 wt% acid treated SiC resulted in the highest dielectric constant of 42 at 1 kHz, in comparison to 25 for the unfilled polymer. This was attributed to increased interfacial polarization arising from uniform dispersion of nanoparticles and abundant charge trapping sites introduced by the SiC filler.

Carbonized metallic organic frameworks (CMOF) have been attracting attention in microwave absorption (MA) research area because of their diverse structures, tunable compositions, and rich porosity. Herein, structure regulation on metal clusters in CMOF is achieved by tuning the interaction strength between metals and ligands to enhance microwave absorption performance. Due to relatively weak interaction among copper cations and ligands, copper nanoclusters (CuNC) can be uniformly formed and embedded within the cobalt/zinc (Co/Zn) CMOF. Firstly, copper cations are added to the Co/Zn bimetallic zeolitic imidazolate frameworks (ZIFs). Secondly, the CMOF composite particles with CuNCs (CuNCs/CoZn-CMOF) were developed by a pyrolysis process. The CuNCs/CoZn-CMOF with an appropriate amount of CuNCs can harmonize both dielectric and magnetic losses. As a result, the minimum reflection loss (RLmin) reaches −45.1 dB at a matching thickness of 2.30 mm and the effective absorption bandwidth (EAB) is 8.80 GHz at a thickness of 3.10 mm. The broadband response to electromagnetic waves is attributed to interfacial polarization at CuNCs surface and heterogeneous interfaces, impedance matching and multiple scattering of electromagnetic waves. This study provides a feasible method to develop CMOF microwave absorption materials with high EAB values. [ABSTRACT FROM AUTHOR]

Rational manipulation of composition and microstructure design is recognized as an effective pathway to realize multifunctional high‐performance microwave absorber. In this work, necklace‐like hollow polyacrylonitrile (PAN)/carbon nanofibers are designed and constructed through a simple continuous electrospinning‐carbonization‐etching route. Specifically, by varying the carbonization temperature, the ratio of PAN to carbon content of necklace‐like hollow PAN/carbon nanofibers can be effectively regulated, resulting in tunable electromagnetic parameters and conductive loss capacities. After that, the hollow structure is further introduced to improve the feature of lightweight, impedance‐matching characteristics, and interfacial polarization loss ability. Accordingly, the necklace‐like hollow PAN/carbon nanofibers exhibited a frequency bandwidth of 6.60 GHz and a minimum reflection loss of −44.73 dB at 1.76 mm. Both the experimental and theoretical simulation results indicated that the obtained necklace‐like hollow PAN/carbon nanofibers possessed the high chemical stability and excellent microwave absorbing performance, endowing them as the excellent candidates for microwave absorbers in the extreme conditions. Therefore, the findings not only offered a simple pathway to rationally manipulate composition and microstructure but also provided a novel technique to make the most of hollow engineering for strengthening interface polarization loss. [ABSTRACT FROM AUTHOR]

Polymer-derived SiAlCN ceramics as sensing materials are promising materials for wireless temperature sensors to achieve application in high-temperature harsh environments. However, limited understanding for the electric and dielectric properties of SiAlCN ceramics restricts the development of wireless sensors. Herein, the electrical and dielectric properties of polymer-derived SiAlCN ceramics pyrolyzed at different temperatures are investigated systemically. The results reveal that the electric resistance of the free-carbon phase and amorphous SiAlCN ceramic phase are comparable, however, the dielectric constant of the ceramic phase is much higher than that of the free-carbon phase. The maximum dielectric constant can reach up to 2.4E+5. Furthermore, the detailed mechanism analysis reveals that the SiAlCN ceramics with different pyrolysis temperatures all obey the same relaxation process, which is interfacial polarization and non-Debye relaxation. The deep understanding of the dielectric property of polymer-derived SiAlCN ceramics is very practical to design wireless sensors for potential applications in high-temperature and harsh environments. [ABSTRACT FROM AUTHOR]

The MAPbBr3 halide perovskite with a cubic paraelectric phase exhibits excellent semiconductor properties. Here, an interfacial polarization (Pin) at the ITO/MAPbBr3 Schottky junction can largely enhance photovoltaic current and be applied in the light and force multifunctional detector. An external force can alter the Pin and increase the photocurrent of the ITO/MAPbBr3/spiro‐OMeTAD/ITO detector, and a 1 N force increases the short‐circuit photocurrent by 120%. Furthermore, the ITO/MAPbBr3/ITO structure with one ITO surface in light and another ITO surface in dark exhibits an equivalent piezoelectric coefficient (d33) of up to 83 pC N−1 since the Pin and the corresponding photovoltaic current dynamically change with periodic external force. The light and force multifunctional detectors will promote the development and blend of optoelectronic devices and MEMS. [ABSTRACT FROM AUTHOR]

The extremely weak heterointerface construction of high‐entropy materials (HEM) hinders them being the electromagnetic wave (EMW) absorbers with ideal properties. To address this issue, this study proposes multiphase interfacial engineering and results in a multiphase‐induced interfacial polarization loss in multielement sulfides. Through the selection of atoms with diverse reaction activities, the multiphase interfacial components of CuS (1 0 5), Fe0.5Ni0.5S2 (2 1 0), and CuFe2S3 (2 0 0) are constructed to enhance the interfacial polarization loss in multielement Cu‐based sulfides. Compared with single‐phase high‐entropy Zn‐based sulfides (ZnFeCoNiCr‐S), the multiphase Cu‐based sulfides (CuFeCoNiCr‐S) possess optimized EMW absorption properties (effective absorption bandwidth (EAB) of 6.70 GHz at 2.00 mm) due to the existence of specific interface of CuS (1 0 5)/CuFe2S3 (2 0 0) with proper EM parameters. Furthermore, single‐phase ZnFeCoNiCr‐S into FeNi2S4 (3 1 1)/(Zn, Fe)S (1 1 1) heterointerface through 400 °C heat‐treated is decomposed. The EMW absorption properties are enhanced by strong interfacial polarization (EAB of 4.83 GHz at 1.45 mm). This work reveals the reasons for the limited EMW absorption properties of high‐entropy sulfides and proposes multiphase interface engineering to improve charge accumulation and polarization between specific interfaces, leading to the enhanced EMW absorption properties. [ABSTRACT FROM AUTHOR]

This study reports copolymer composition tailored wrapping of carbon nanotubes, leading to a gigantic dielectric permittivity and peculiar nonlinear rheological response in a nonfluoro copolymer/carbon nanotube (CNT) hybrid system. Specifically, we observed a strong interfacial polarization effect in ethylene vinyl acetate (EVAc) copolymer/CNT nanocomposites, resulting in a dielectric permittivity of approximately 4000 at 10 Hz and 450 (dielectric loss <1) at 1 kHz, with only 1% volume fraction of CNTs and 40% vinyl acetate (VAc) content. No such effect was observed in EVAc with 12% VAc. Extensive amplitude oscillatory rheology studies prompted us to propose a novel hook‐wrap‐type mechanism, wherein polar interactions act as hooks and nonpolar segments allow wrapping, depending on the optimal interactions between the CNT and copolymer. Raman spectroscopy, small‐angle x‐ray scattering, and relaxation studies also revealed a significant change in segmental dynamics and mass fractal compactness with a change in the VAc content. This work provides a melt processing‐based scalable route to develop polymer dielectrics while advancing the fundamental understanding of polymer‐CNT interactions and the underlying mechanisms of dielectric behavior in nanocomposites. [ABSTRACT FROM AUTHOR]

Restricted growth of molybdenum carbide nanoparticles in hierarchically porous nitrogen-doped carbon matrix was prepared, which exhibits satisfactory electromagnetic wave absorption properties. This work enriches the variety of EMW absorbers and offers the route to promote the EMW absorption performance, especially large effective absorption bandwidth. [Display omitted] • MO 2 C/NC composites with honeycomb porous structure was synthesized; • This strategy enriches the variety of high-performance absorbers with mass production; • Bandwidth of 9.6 GHz at 3.5 mm was achieved for electromagnetic wave absorber; • Analysis of the absorption mechanism of MO 2 C/NC absorbers was investigated. With the development of electronic science and technology, electromagnetic pollution is becoming increasingly serious, which urgent people to develop wave-absorbing materials with the features of "thin, light, strong and wide". In this paper, restricted growth of molybdenum carbide nanoparticles in hierarchically porous nitrogen-doped carbon matrix (Mo 2 C/NC) was designed and prepared via a salt-assisted template route and carbonization process, whose morphology and the wave-absorbing properties are regulated by changing the content of Mo 2 C/NC nanoparticles. The honeycomb porous Mo 2 C/NC composites with large specific surface area and smooth surface can optimize the impedance matching and allow the entrance, multiple reflections and scattering of incident electromagnetic waves (EMW), which effective enhance the electromagnetic wave consumption. Meanwhile, the honeycomb cross-linked carbon matrix facilitates the construction of the conductive network and enhances its conductive loss. Furthermore, numerous Mo 2 C/NC nanoparticles dispersed restricted growth in carbon matrix induces interfacial polarization. In addition, the heteroatom nitrogen doping acts as dipole centers to induce dipole polarization under electromagnetic field. The uniquely designed Mo 2 C/NC absorbers show satisfactory EMW absorption behaviors of a minimum reflection loss (RL min) of −61.53 dB at 1.5 mm and an effective absorption bandwidth (EAB) of 9.6 GHz at 3.5 mm. This work enriches the variety of EMW absorbers and offers the route to promote the EMW absorption performance, especially large effective absorption bandwidth. [ABSTRACT FROM AUTHOR]

[Display omitted] • The cubic TiO 2 and MnFe 2 O 4 nanoparticles bind tightly with Ti 3 C 2 T x from in-situ growth and self-assembly method, respectively. • Enhanced interfacial polarization comes from the TiO 2 and MnFe 2 O 4 interacting ways with Ti 3 C 2 T x. • The fabric coated with the composites have MA effect, heat dissipation, and hydrophobic property. Despite the fact that the 2D structure Ti 3 C 2 T x with abundant defects and functional groups contributes to the high microwave absorption (MA) performance, it is difficulty to improve the strength and bandwidth by pursuing higher conductivity or loading more groups due to the limitation of intrinsic properties. Therefore, it is important to ingeniously design efficient Ti 3 C 2 T x based MA composites assembling the features of abundant surface groups, good dispersibility, multiple composition, and precise structure. Inspired by the fact that Ti 3 C 2 T x contains thermodynamically metastable marginal Ti atoms, TiO 2 nanoparticles can be grown in-situ on Ti 3 C 2 T x nanosheets uniformly and increase the spacing of Ti 3 C 2 T x layers, and then MnFe 2 O 4 nanoparticles are introduced into the layers of Ti 3 C 2 T x by electrostatic self-assembly method for optimized impedance matching. This designed hierarchical MnFe 2 O 4 /TiO 2 /Ti 3 C 2 T x composites shows excellent MA performance, and the minimum reflection loss (RL min) reaches −46.91 dB with a thickness of 2.5 mm at frequency of 10.4 GHz. The high MA performance mainly comes from the enhanced interfacial polarization induced by edges location and interface region among TiO 2 , MnFe 2 O 4 , and Ti 3 C 2 T x. In addition, the conduction loss existed in the interior untreated Ti 3 C 2 T x , the dielectric loss generated by multiple composition, the multiple scattering from improved large surface specific area all contribute to the excellent MA performance. Meanwhile, the simple preparation process and good stability storage at room temperature under air atmosphere of the MnFe 2 O 4 /TiO 2 /Ti 3 C 2 T x composites promote its exploration on practical use, and the lab-gown cloth coated with MnFe 2 O 4 /TiO 2 /Ti 3 C 2 T x composites shows better electromagnetic shielding properties, hydrophobicity, and heat transfer ability than pure fabric, showing the potential for practical application. [ABSTRACT FROM AUTHOR]

This work investigates the enhancement of dielectric properties of La 2 NiO 4 -CuO terpolymer nanocomposites using surface modified SiC nanoparticles as fillers. SiC nanoparticles were subjected to acid treatment and annealing at 1000 °C to tailor the surface chemistry. Acid treatment involved immersing the SiC powder in a mixture of H 2 SO 4 and HNO 3 acids and sonicating for 30 min, followed by stirring at 60 °C for 6 h. Annealing was carried out at 1000 °C for 2 h in an inert argon atmosphere. La 2 NiO 4 and CuO nanoparticles were synthesized by sol-gel and precipitation techniques respectively, with average particle sizes of 20–40 nm and 10–15 nm confirmed by XRD and FESEM. Nanocomposites were fabricated by dispersing 2–10 wt% of untreated, acid treated and annealed SiC nanoparticles in a La 2 NiO 4 -CuO mixture solution, using PVDF as the polymer matrix. Impedance spectroscopy revealed that addition of 5 wt% acid treated SiC resulted in the highest dielectric constant of 42 at 1 kHz, in comparison to 25 for the unfilled polymer. This was attributed to increased interfacial polarization arising from uniform dispersion of nanoparticles and abundant charge trapping sites introduced by the SiC filler. [ABSTRACT FROM AUTHOR]

In the ever‐evolving landscape of complex electromagnetic (EM) environments, the demand for EM‐attenuating materials with multiple functionalities has grown. 1D metals, known for their high conductivity and ability to form networks that facilitate electron migration, stand out as promising candidates for EM attenuation. Presently, they find primary use in electromagnetic interference (EMI) shielding, but achieving a dual‐purpose application for EMI shielding and microwave absorption (MA) remains a challenge. In this context, Sn whiskers derived from the Ti2SnC MAX phase exhibit exceptional EMI shielding and MA properties. A minimum reflection loss of −44.82 dB is achievable at lower loading ratios, while higher loading ratios yield efficient EMI shielding effectiveness of 42.78 dB. These qualities result from a delicate balance between impedance matching and EM energy attenuation via adjustable conductive networks; and the enhanced interfacial polarization effect at the cylindrical heterogeneous interface between Sn and SnO2, visually characterized through off‐axis electron holography, also contributes to the impressive performance. Considering the compositional diversity of MAX phases and the scalable fabrication approach with environmental friendliness, this study provides a valuable pathway to multifunctional EM attenuating materials based on 1D metals. [ABSTRACT FROM AUTHOR]

A novel core/shell nanoferrite material has been developed for use in various potential applications. Rare-earth doped calcium-ferrite with the compositional formula CaFe 1.925 Sm 0.05 Gd 0.025 O 4 was prepared as a core using the citrate auto-combustion method before being coated with PVA as a polymeric shell. High crystalline and single-phase orthorhombic nanoparticles are confirmed by XR-D (X-ray diffraction). An estimate has been made for the mean size of the crystal structures by analyzing the broadening of XR-D lines within a range of 20 nanometers. HR-TEM (high-resolution tunnelling electron microscope) micrographs also showed that the particles had an orthorhombic shape with well-defined boundaries. EDX (energy-dispersive X-ray) and FT-IR were used to investigate the elemental constitution and the molecular structure of samples. The dielectric properties were discussed in the basics of interfacial polarization and Koop's model. The anti-ferromagnetic nature of the samples was identified by a VSM (vibrating sample magnetometer). The proposed composition was found to improve the electromagnetic absorption performance, which was confirmed with the measurements of optical parameters from the absorbance spectrum recorded by the UV–VIS–NIR spectroscope. The optical band-gap and Urbach energies of the synthesized samples have been investigated, in addition to the refractive index and the extinction coefficient. The Wemple-DiDomenico oscillator model was used to examine the dispersion energies. [ABSTRACT FROM AUTHOR]

The conductive properties of CNT/polymer composites have been extensively studied. However, the impact of CNT distribution in the matrix on the composite polarization remains underexplored and poorly understood. Since it is difficult to achieve a uniform distribution of CNTs in polymers, most researchers have focused only on indiscriminately aggregated states. In this article, a new blending method was suggested to prepare a series of epoxy resin-based composite samples with varying levels of CNT uniformity/aggregation and the same filling fractions. Notably, the permittivity values turned out to be inversely related to the composite uniformity: the lowest permittivity values were obtained in the most uniform formulation, and vice versa. With 0.1% CNT, the real part values of the most uniform and aggregated samples were 6.6 and 16.2 at 107 Hz and 11.6 and 370.5 at 101 Hz, respectively. For the filler content of 0.1–0.5%, the conductive properties were largely determined by the distribution of CNTs and not their content. Within the entire frequency range, the uniform sample with 0.2% CNT exhibited significantly lower permittivity than the aggregated sample with 0.1% CNT. These findings emphasize the importance of the aggregation factor and underscore the non-universality and limitations of the percolation theory and power laws. The observed phenomenon is best explained by the micro-capacitor model, or the Maxwell–Wagner polarization, and suggests that a significant portion of the literature in the field needs to be reconsidered.

Abstract Flexible piezoelectric pressure sensors (FPPS) received a lot of attention because of their prominent performance in body motion detection and energy recovery. However, it has faced a huge challenge in manufacturing FPPS with high sensitivity, low cost, and high flexibility. Herein, a ternary flexible nanofiber composite with Sb nanosheets and BaTiO3 nanoparticles as the fillers of P(VDF‐TrFE) is prepared by electrospinning. An impressive open‐circuit voltage of 17.1 V and short‐circuit current of 4.4 µA is obtained based on the composite nanofiber mat at a pressure of 128 kPa with 2 Hz frequency. The FPPS not only exhibit a high sensitivity of 96 mV kPa−1 but also an ultrafast response time of 2 ms. Excellent flexibility and reliability are demonstrated by the unchanged open‐circuit voltage after 2400 cycles. The enhanced FPPS performance is owed to the interfacial polarization effect at the inorganic filler‐organic matrix interface, which also enhances the ferroelectric and dielectric properties. The present FPPS is further confirmed to be a real‐time motion monitor and voice recognizer, which can distinguish various actions and sounds according to distinct output voltage signals and is expected to be used in virtual reality devices, robotic electronic skin, haptic simulation, artificial throat, etc.

In order to obtain the microwave absorption (MA) materials with light weight, high efficiency and tunable properties, the carbonized mesophase pitch (CMP) with the variation in carbonization temperatures and particle sizes were prepared and characterized. The carbonization temperature mainly controlled the graphitization degree of the CMP to affect their conductive loss. The carbon residues were generated on the CMP surface when the temperature was higher than 700 °C, which contributed significantly to the polarization loss of the CMP. For scale regulation, the segregation between the particles in the paraffin ring caused by the reduction particles of CMP carbonization at 750 °C (750 CMP) resulted in a significant reduction in conductive losses while improving their impedance matching. The 750 CMP over 300 mesh sieved had the strongest MA properties of −53 dB at 3.49 GHz within 5.5 mm. Moreover, the prepared CMPs were multi-layer compounded and optimized by CST microwave studio. The synergistic effect derived from the improved impedance matching and the enhanced interfacial polarization resulted in significant reflection loss in multi-layer CMP. Overall, these findings lead to the systematically regulation of carbon-based materials for MA, showing an attractive application prospect for the preparation of high-performance MA materials.

High-performance lead-free energy storage ceramic materials are one of the important materials for environmentally friendly electronic devices. Here, lead-free NaNbO 3 (NN)-based relaxor ceramics, NaNbO 3 - x BiMg 0.5 Hf 0.5 O 3 (NN- x BMH, x = 0.05, 0.10, 0.15, and 0.20), were obtained by solid-state reaction method. Our results show that the introduction of BMH greatly improves the relaxor behavior, enhancing domain switching capability. As increasing BMH content, the large band gap leads to improve the breakdown field strength. A high energy storage (W r = 5.00 J/cm3) and efficiency (η = 83.1%) were obtained in the NN-0.15BMH ceramic. In addition, the discharge energy density of NN-0.15BMH ceramic can be kept at 3.15 J/cm3 at 300 kV/cm, showing excellent charge and discharge performance. This work confirms that the method of band and domain engineering is a facile strategy for high-performance energy storage ceramics. [ABSTRACT FROM AUTHOR]

[Display omitted] • The N -doped-rGO/g-C 3 N 4 was prepared for the first time, its density is only 0.035 g/cm3. • The impedance matching of the N -doped-rGO/g-C 3 N 4 composite was well adjusted by g-C 3 N 4. • g-C 3 N 4 distributing among N -doped-rGO sheets can produce more polarization effect and relaxation effect by increasing the lamellar spacing. • N atoms are doped into rGO successfully, C-N dipoles can produce dipole polarization and further attenuating incident waves. • The RL min of N -doped-rGO/g-C 3 N 4 could reach −49.59 dB, the EAB could reach 4.56 GHz with the filling loading of 5 wt% when the thickness was 1.6 mm. "Thin thickness", "lightweight", "wide absorption bandwidth" and "strong absorption" are the new standards of contemporary science and technology for microwave absorption(MA) material. In this study, N -doped-rGO/g-C 3 N 4 MA material was prepared for the first time by simple heat treatment, which the N atoms were doped into rGO and g-C 3 N 4 was dispersed on the surface of N -doped-rGO, and its density is only 0.035 g/cm3. The impedance matching of the N -doped-rGO/g-C 3 N 4 composite was well adjusted by decreasing the dielectric constant and attenuation constant due to the g-C 3 N 4 semiconductor property and the graphite-like structure. Moreover, the distribution of g-C 3 N 4 among N -doped-rGO sheets can produce more polarization effect and relaxation effect by increasing the lamellar spacing. Furthermore, the polarization loss of N -doped-rGO/g-C 3 N 4 could be increased successfully by doping N atoms and g-C 3 N 4. Ultimately, the MA property of N -doped-rGO/g-C 3 N 4 composite was optimized significantly, with a loading of 5 wt%, the N -doped-rGO/g-C 3 N 4 composite exhibited the RL min of −49.59 dB and the effective absorption bandwidth could reach 4.56 GHz when the thickness was only 1.6 mm. The "thin thickness", "lightweight", "wide absorption bandwidth" and "strong absorption" of MA material are actually achieved by the N -doped-rGO/g-C 3 N 4. [ABSTRACT FROM AUTHOR]

The harm of electromagnetic wave to human daily life has gradually received widespread attention, and CuS, with unique morphology and high specific surface area, and as a typical P‐type semiconductor material, has a large number of holes, which is conducive to electron transport, which have used as electromagnetic wave absorption (EMA) materials. EMA properties are affected by the morphology of materials, and therefore, flower‐shaped CuS/reduced graphene oxide (RGO) formed by self‐assembly of 2D lamellar structure CuS and RGO is prepared via a simple water bath–heating reaction. The content of RGO was adjusted to obtain the superior EMA properties. In the results, it is shown that the synthesized CuS/RGO with RGO of 10 mg has an excellent EMA capacity of strong reflection loss (RLmin = −46.8 dB) and broad effective absorption bandwidth (EAB = 4.9 GHz), at the thickness of 2.04 mm and the frequency of 12.1 GHz. The prepared flower‐shaped CuS/RGO composites has a strong interface polarization because of its 2D/2D heterostructure, and the 2D CuS was compounded with 2D RGO to form 3D conductive networks improving conductive loss capacity. In this article, the study on the influence of the morphology of transition‐metal sulfides–based composites on EMA field is enriched. [ABSTRACT FROM AUTHOR]

Extensive utilization of electronic devices and wireless equipment require human to take affirmative measures to weaken unwanted electromagnetic wave radiations. Herein, a ferroelectric poly[(vinylidenefluoride‐co‐trifluoroethylene) (P(VDF‐TrFE)‐MXene]‐poly(3,4‐ethylenedioxythiophene) (PEDOT) multilayered film is developed that can increase electromagnetic interference (EMI) shielding performance through electrical polarization. The MXene is encapsulated by a P(VDF‐TrFE) matrix, which inhibits oxidation, and a highly conductive MXene is created conductive network resulting in enhancement EMI shielding effectiveness (EMI SE). Furthermore, the surface pattern inducing multiple scattering and PEDOT layer contributes to the increasing absorption due to the electrically conductive PEDOT. Thanks to the electrically polarized and negatively charged P(VDF‐TrFE)‐MXene, the composite film demonstrates superior EMI SE and absolute EMI SE (SSEt) are exhibited remarkable ≈61 dB and 15230 dB cm2g−1 with high absorptivity (0.87) at thickness of 120 µm in X‐band. Additionally, P(VDF‐TrFE)‐MXene composite film is applicable to motion and thermo‐resistive sensor due to the negatively charged P(VDF‐TrFE) and thermo‐resistive property of PEDOT, respectively, for multifunctionality. This work provides a feasible avenue for flexible absorption dominant EMI shielding materials via electrical polarization with remarkable EMI shielding performance. [ABSTRACT FROM AUTHOR]

Abstract The extremely weak heterointerface construction of high‐entropy materials (HEM) hinders them being the electromagnetic wave (EMW) absorbers with ideal properties. To address this issue, this study proposes multiphase interfacial engineering and results in a multiphase‐induced interfacial polarization loss in multielement sulfides. Through the selection of atoms with diverse reaction activities, the multiphase interfacial components of CuS (1 0 5), Fe0.5Ni0.5S2 (2 1 0), and CuFe2S3 (2 0 0) are constructed to enhance the interfacial polarization loss in multielement Cu‐based sulfides. Compared with single‐phase high‐entropy Zn‐based sulfides (ZnFeCoNiCr‐S), the multiphase Cu‐based sulfides (CuFeCoNiCr‐S) possess optimized EMW absorption properties (effective absorption bandwidth (EAB) of 6.70 GHz at 2.00 mm) due to the existence of specific interface of CuS (1 0 5)/CuFe2S3 (2 0 0) with proper EM parameters. Furthermore, single‐phase ZnFeCoNiCr‐S into FeNi2S4 (3 1 1)/(Zn, Fe)S (1 1 1) heterointerface through 400 °C heat‐treated is decomposed. The EMW absorption properties are enhanced by strong interfacial polarization (EAB of 4.83 GHz at 1.45 mm). This work reveals the reasons for the limited EMW absorption properties of high‐entropy sulfides and proposes multiphase interface engineering to improve charge accumulation and polarization between specific interfaces, leading to the enhanced EMW absorption properties.

Highlights rGO/MXene/TiO2/Fe2C heterointerface porous microspheres prepared via scalable method to boost polarization. Customization of hierarchical structure by precisely tuning 2D rGO/MXene intercalation. Optimal reflection loss of -67.4 dB and EAB = 5.47 GHz at low filler loading of 5 wt%. Simulations showed the benefits of 2D nanosheets intercalation on polarization loss.

Ti3C2Tx MXene shows great potential in the application as microwave absorbers due to its high attenuation ability. However, excessively high permittivity and self-stacking are the main obstacles that constrain its wide range of applications. To tackle these problems, herein, the microspheres of SiO2@Ti3C2Tx@CoNi with the hydrangea-like core–shell structure were designed and prepared by a combinatorial electrostatic assembly and hydrothermal reaction method. These microspheres are constructed by an outside layer of CoNi nanosheets and intermediate Ti3C2Tx MXene nanosheets wrapping on the core of modified SiO2, engendering both homogenous and heterogeneous interfaces. Such trilayer SiO2@Ti3C2Tx@CoNi microspheres are "magnetic microsize supercapacitors" that can not only induce dielectric loss and magnetic loss but also provide multilayer interfaces to enhance the interfacial polarization. The optimized impedance matching and core–shell structure could boost the reflection loss (RL) by electromagnetic synergy. The synthesized SiO2@Ti3C2Tx@CoNi microspheres demonstrate outstanding microwave absorption (MA) performance benefited from these advantages. The obtained RL value was −63.95 dB at an ultra-thin thickness of 1.2 mm, corresponding to an effective absorption bandwidth (EAB) of 4.56 GHz. This work demonstrates that the trilayer core–shell structure designing strategy is highly efficient for tuning the MA performance of MXene-based microspheres.

Due to their tailorable morphology, silica nanoparticles (SNPs) have recently attracted widespread attention because they can be used in many emerging areas. Over the past decade, important work has been done on novel processing methodologies to prepare SNPs, which have resulted in better control over the size, shape, porosity, and notable improvements in their physio-chemical properties. Microemulsions are a simple and widely used method of preparing silica nanoparticles. The method, however, still has several flaws, such as the inability to produce the expected silica nanoparticles even under carefully designed synthesis conditions. In order to effectively use silica nanoparticles (SNs) in catalyst, adsorption, polymer filler, optical devices, bio-imaging, drug delivery, and biomedical applications, it is becoming more and more crucial to have good control over their morphology, particle size, uniformity, and dispersity. It is therefore desirable to monitor the synthesis process in real time to unravel the mechanisms behind the formation of silica nanoparticles and to promote their controllable synthesis. It has always been a hot topic in nano science to apply microemulsions using different types of surfactants to inorganic nanomaterials. Despite this, very few studies have been performed on polymer-based microemulsions based on different ionic surfactants and their relative dielectric spectroscopy (DS). This review examines various synthesis techniques for producing well-dispersed SNs and hollow silica nanoparticles (HSNs) with adjustable dimensions ranging from a few to hundreds of nanometers of various mesostructures.

The symmetry in a polymorph is one of the most important elements for determining the inherent lattice nature. The MnO2 host tends to high‐symmetry MnO6 octahedra as a result of the electronic structure t2g3eg0 of Mn4+ ions, displaying an ordered structure accompanying with poor polarization loss and limiting its application toward high‐performance microwave absorbers. Here, a pseudo‐Jahn−Teller (PJT) distortion and PJT disordering design with abundant self‐forming interfaces and local magnetic domains in the monoclinic birnessite–MnO2 host is first reported. The PJT distortion can give rise to asymmetric MnO6 octahedra, inducing the formation of interfaces and increased electron spin magnetic moment in the lattice. The resultant birnessite with PJT distortions and PJT disordering delivers an outstanding reflection loss value of −42.5 dB at an ultralow thickness of 1.7 mm, mainly derived from the excited interfacial polarization and magnetic loss. This work demonstrates an effective approach in regulating the lattice structure of birnessite for boosting microwave absorption performance. [ABSTRACT FROM AUTHOR]

Benefiting from the plasma-sprayed technology for its practical application in the field of microwave absorption, this research provides a strategy by tailoring synergistic effect of dielectric loss and conduction loss for oxygen vacancy-mediated Ti 4 O 7 material to broaden the application of absorbing or shielding ceramic coatings. [Display omitted] • The Ti 4 O 7 ceramic coatings with high flexural strength, strong electromagnetic absorption and shielding performance are fabricated by using plasma spraying technology for the first time. • The innovative dual losses effect of oxygen-defective Ti 4 O 7 combined with CNTs makes the charge arrangement non-uniform and promotes the dielectric polarization. • The optimal reflection loss of Ti 4 O 7 /Al 2 O 3 coating reaches −55.7 dB at 2.41 mm due to the appropriate components, abundant defects, impedance matching and multi-dielectric polarization. High-performance microwave absorption coatings are critically required in the stealth defense system of military platforms. Regrettably, just optimizing the property but neglecting the application feasibility seriously inhibits its practical application in the field of microwave absorption. To face this challenge, the Ti 4 O 7 /carbon nanotubes (CNTs)/Al 2 O 3 coatings were successfully fabricated by a plasma-sprayed method. For the different oxygen vacancy-induced Ti 4 O 7 coatings, the enhanced ε' and ε'' values in the frequency of X-band is due to the synergistic manipulation of conductive path, defects and interfacial polarization. The optimal reflection loss of Ti 4 O 7 /CNTs/Al 2 O 3 sample (0 wt% CNTs) is −55.7 dB (8.9 GHz of 2.41 mm), while the electromagnetic interference shielding effectiveness of Ti 4 O 7 /CNTs/Al 2 O 3 sample (5 wt% CNTs) increases to 20.5 dB as the enhanced electrical conductivity. In special, the flexural strength of Ti 4 O 7 /CNTs/Al 2 O 3 coatings first increases from 48.59 MPa (0 wt% CNTs) to 67.13 MPa (2.5 wt% CNTs) and then decreases to 38.31 MPa (5 wt% CNTs), demonstrating that an appropriate amount of CNTs evenly dispersed in the Ti 4 O 7 /Al 2 O 3 ceramic matrix can effectively play the role of CNTs as the strengthening phase of the coatings. This research will provide a strategy by tailoring synergistic effect of dielectric loss and conduction loss for oxygen vacancy-mediated Ti 4 O 7 material to broaden the application of absorbing or shielding ceramic coatings. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cu/CuFe 2 O 4 composites with ant nest-like microstructure were synthesized for the first time. • The symbiosis of Cu on CuFe 2 O 4 raise the intrinsic complex permittivity of pure CuFe 2 O 4. • The effective absorption bandwidth is 6.32 GHz at 1.7 mm and RL min is −48.81 dB. • Interfacial polarization and conductance loss are leading attenuation mechanism. Low complex permittivity and easy magnetic agglomeration prevent ferrites from achieving high-efficiency electromagnetic wave (EMW) absorption owing to the resultant narrow absorption bandwidth. Existing composition- and morphology-controlled strategies have made limited progress in fundamentally improving the intrinsic complex permittivity and absorption performance of pure ferrite. In this study, Cu/CuFe 2 O 4 composites were synthesized using a facile and low-energy sol-gel self-propagating combustion, and the metallic Cu content was adjusted by changing the ratio of the reductant (citric acid) to the oxidant (ferric nitrate). The symbiosis and coexistence of metallic Cu with ferritic CuFe 2 O 4 increases the intrinsic complex permittivity of CuFe 2 O 4 , which can be regulated by changing the metallic Cu content. Moreover, the unique ant-nest-like microstructure overcomes the issue of magnetic agglomeration. Because of the favorable impedance matching and strong dielectric loss (interfacial polarization and conduction loss) provided by the moderate metallic Cu content, S0.5 concurrently displays broadband absorption with an effective absorption bandwidth (EAB) of 6.32 GHz at an ultrathin thickness of 1.7 mm and strong absorption relying on minimum reflection loss (RL min) of −48.81 dB at 4.08 GHz and 4.0 mm. This study provides a new perspective for improving the EMW absorption performance of ferrites. [ABSTRACT FROM AUTHOR]

Semiconductor metal oxides are widely used in the field of wave absorption because of their easily tunable dielectric properties. Doping or modulating the morphology has been demonstrated to be an effective method to improve the microwave (MW) absorbing performance of semiconductor metal oxides. In this study, Ce-doped SnO 2 was prepared by a simple and effective coprecipitation method. Single-crystal SnO 2 nanorods were generated during the doping process and the size of the nanorods could be controlled by modifying the concentration of Ce. The presence of nanorods greatly enhances the MW absorbing performance: when the doping molar ratio is 3%, the minimum reflection loss of the absorber is −77.91 dB at a frequency of 13.79 GHz with a thickness of 1.6 mm and the maximum effective absorbing bandwidth is 4.47 GHz at a thickness of 1.5 mm. Excellent MW absorbing performance of Ce-doped SnO 2 is attributed to its excellent impedance matching and interfacial polarization. [ABSTRACT FROM AUTHOR]

Constructing magnetic–dielectric composites has proved to be an effective strategy for producing high-performance electromagnetic (EM) absorbers. In this study, a novel absorber composed of NiCo2O4 microspheres and biochar derived from transparent fish gelatin was synthesized through a facile solvothermal process. The absorber exhibited excellent attenuation ability with an absorption intensity of − 30.2 dB at 1.5 mm and a broad bandwidth of 5.2 GHz. A comprehensive analysis of the microstructure and composition distribution of the composite was conducted in order to understand the correlation with the absorption performance. Additionally, the study discussed the microstructural evolution during high-temperature carbonization. Such absorber could be promoted as lightweight and high-efficiency absorbing materials, and this work provides inspiration for the construction of advanced absorbers with strong dissipation capacity and broad effective bandwidth. [ABSTRACT FROM AUTHOR]

MXenes have recently emerged as a new class of electrocatalysts for diverse energy conversion reactions, but they are generally considered to be catalytically inert. Herein, a strategy of interfacial polarization is put forward to improve the catalytic activity of MXenes, with the construction of an interfacial structure consisting of black phosphorus (BP) nanoflakes and Nb2C MXene nanosheets for electrochemical nitrate reduction to ammonia as a proof of concept. The experimental and computational results reveal that a strong interfacial polarization is built between BP nanoflakes and Nb2C nanosheets in the prepared BP/Nb2C composite. The polarization of Nb centers by adjacent BP sites gives rise to the formation of positively centered Nb atoms and BP‐polarized Nb atoms, which synergistically catalyze the cleavage of N–O bonds in HNO2* to form NO*. In addition, the stabilization of monatomic *N by the BP/Nb2C composite is also enhanced compared with BP nanoflakes and Nb2C nanosheets. As a result, both the ammonia yield rate and Faraday efficiency of the BP/Nb2C composite are much higher than that of BP nanoflakes and Nb2C nanosheets. Overall, this work shows the great potential for constructing a strong interfacial polarization to improve the catalytic performance of MXenes‐based electrocatalysts. [ABSTRACT FROM AUTHOR]