Barium titanate, BaTiO3 (BTO) is the most common ferro electric material, which is used to manufacture electronic components such as multilayer capacitors, positive temperature coefficient thermistors, piezo electric ...Barium titanate, BaTiO3 (BTO) is the most common ferro electric material, which is used to manufacture electronic components such as multilayer capacitors, positive temperature coefficient thermistors, piezo electric transdures, and ferro electric memory. Zr doped barium magnesium titanate (Ba0.9Mg1.0)(ZrxTi1-x)O3 (with x = 0.10, 0.20, 0.40 (BMZT 10, BMZT 20 and BMZT 40) perovskite is prepared by conventional solid state reaction method. The starting raw materials were BaCO3, TiO2, MgO and ZrO2. The XRD study at room temperature suggests that these have cubic and tetragonal symmetry phases. The behavior of the measured dielectric permittivity and dielectric loss with temperature and frequency reveals that the materials undergo a diffuse para-ferroelectric phase transition and are of the relaxor type. The crystal structure, surface morphology and dielectric properties of Zr and Mg doped barium titanate ceramics were investigated. Zr4+ and Mg2+ ions have entered the unit cell maintaining the perovskite structure of solid solution without the evidence of any additional phase when Mg content is 0.1 mole% and the Zr content is 0.10, 0.20 and 0.40 mole%.展开更多
The spectra of the dielectrical constant and dielectrical loss in three nanostructured a-Fe2O3 samples at different annealed temperatures are measured by using ac LRC method. The relaxation times of polarization and t...The spectra of the dielectrical constant and dielectrical loss in three nanostructured a-Fe2O3 samples at different annealed temperatures are measured by using ac LRC method. The relaxation times of polarization and the conductance are calculated by means of the Debye mechanism and the interface effects in two kinds of polarization processes with two different relaxation times are proposed.展开更多
A new,cost-effective porous polymer composite was developed by reinforcing polypropylene(PP)with cenosphere particles.This study investigates how the composite’s dielectric properties are affected by their porosity.D...A new,cost-effective porous polymer composite was developed by reinforcing polypropylene(PP)with cenosphere particles.This study investigates how the composite’s dielectric properties are affected by their porosity.Dielectric constant(ε′)measurements were taken over a range of frequencies at roomtemperature.A theoreticalmodel was developed to explain the electrical conductivity of the porous PP/cenosphere composites.The study thoroughly examined how the inclusion of cenosphere particles influenced key electrical parameters,including dielectric constant,dissipation factor(tanδ),DC(direct current)conductivity,and AC(alternating current)conductivity.The results revealed that increasing the cenosphere content caused a decrease in the dielectric constant,while the dissipation factor increased.The developed porous PP/cenosphere composite exhibits a unique balance of low dielectric constant,lightweight structure making it suitable for several practical applications.Its low dielectric constant and reduced DC conductivity make it an excellent candidate for electronic packaging,insulating layers,and high-frequency components,where minimal energy loss and signal interference are required.The lightweight nature of the cenosphere-reinforced structure also suggests potential use in aerospace and automotive industries for lightweight insulation panels or structural components.Furthermore,its cost-effectiveness and tunable porosity could enable applications in microwave substrates,radar-absorbing materials,and energy-efficient building materials where dielectric control and weight reduction are critical.Additionally,DC conductivity was found to decline with higher cenosphere concentrations.The theoretical model was in good agreement with the experimental data.展开更多
The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and ...The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.展开更多
Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives int...Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives interest in metal-organic frameworks(MOFs),which offer high surface area,tunable porosity,and customizable chemical functionality that can help overcome these limitations.In this review,we thoroughly analyze the application of MOFs in TENGs by exploring structural design strategies,ligand modifications,and layer engineering,as well as assessing performance results from recent studies.We highlight essential findings indicating that electron-withdrawing groups,such as-NO_(2),-F,and-SO_(3)H,notably increase tribonegativity.Additionally,doping with conductive nanomaterials and employing machine learning approaches further boost power density.Finally,we propose that future advancements in this area should focus on addressing environmental sensitivity,mechanical brittleness,and synthesis complexity through molecular-level tailoring combined with scalable device engineering,ultimately paving the way for durable,high-efficiency MOF-based TENGs.展开更多
As circuit feature sizes approach the nanoscale,traditional Copper(Cu)interconnects face significant hurdles posed by rising resistance-capacitance(RC)delay,electromigration,and high power dissipation.These limitation...As circuit feature sizes approach the nanoscale,traditional Copper(Cu)interconnects face significant hurdles posed by rising resistance-capacitance(RC)delay,electromigration,and high power dissipation.These limitations impose constraints on the scalability and reliability of future semiconductor technologies.Our paper describes the new Vertical multilayer Aluminium Boron Nitride Nanoribbon(AlBN)interconnect structure,integrated with Density functional theory(DFT)using first-principles calculations.This study explores AlBN-based nanostructures with doping of 1Cu,2Cu,1Fe(Iron),and 2Fe for the application of Very Large Scale Integration(VLSI)interconnects.The AlBN structure utilized the advantages of vertical multilayer interconnects to both reduce the RC delay while enhancing signal integrity.Key parameters like Fermi energy,bandgap,binding energy,conduction channels,quantum resistance,and RC delay were analyzed.Through modeling and large-scale simulation,the structural,electronic,and stability attributes of the AlBN interconnects are analyzed,and the results illustrate considerable improvements in signal propagation against Cu interconnect structures.These findings confirm the tunable,high-performance nature of AlBN-2Fe,making it a promising candidate for future high-speed,low-power VLSI interconnect technologies.We demonstrated an advanced energy-efficient interconnect that can be easily scaled for future nanoscale VLSI circuit design and gives rise to a next generation of viable interconnect technology for high-capacity,high-speed,reliable semiconductor technology.展开更多
Polyurethane elastomers exhibit high dielectric constants owing to their polar groups,and can be used as energy storage capacitors.Energy storage depends not only on the dielectric constant but also on the dielectric ...Polyurethane elastomers exhibit high dielectric constants owing to their polar groups,and can be used as energy storage capacitors.Energy storage depends not only on the dielectric constant but also on the dielectric loss.However,the relationship between chain structure and dielectric properties is not yet clear.Ketal-containing crosslinked polyurethane elastomers were prepared using cyclic ketal diol as a chain extender.The effect of the soft segment length on the dielectric properties and energy storage was investigated.The cause of the change in the dipolar polarization with the soft segment length was analyzed.As the soft segment length increased,the hard-soft hydrogen bonding decreased,whereas the hard-hard hydrogen bonding increased.Under the action of an electric field,the polar bonds in the ketal-containing polyurethane elastomer overcome the hydrogen bonding between hard-soft segments to produce polarization;meanwhile,they also experience crankshaft motions to generate polarization.The former has a relatively high relaxation activation energy of approximately 10-20 k J·mol^(-1),resulting in a large dielectric loss.The latter has a relatively low relaxation activation energy,approximately 0.7-1.7 kJ·mol^(-1),leading to low dielectric loss.As a result,the dielectric constant showed a decreasing trend,and the dielectric loss gradually decreased.This study provides a theoretical foundation for improving the dielectric properties of polyurethane elastomers.展开更多
The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such...The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such as ferrites and metal powders,show excellent magnetic loss performance at room temperature,they have significant limitations in harsh environments due to their high density,low Curie temperature,and susceptibility to oxidation.In contrast,carbon-containing materials have emerged as promising candidates for high-temperature EWA applications,owing to their high melting point,low density,tunable dielectric loss mechanisms,and superior thermal stability.Unlike magnetic materials,carbon-based systems primarily dissipate electromagnetic energy through conductance loss,dipole polarization,and interfacial polarization,thereby avoiding performance degradation at elevated temperatures.However,several critical challenges remain,including insufficient oxidation resistance,mechanical reliability issues,and the need for stable impedance matching.To address these limitations,recent strategies such as defect engineering,heterointerface construction,and metamaterial design have been proposed to enhance thermal stability and functional performance.This review provides a systematic summary of recent advances in carbon-containing absorbers,with a focus on dielectric loss mechanisms,optimization strategies,and multiscale structural design principles.By elucidating the structure–property relationships of carbon materials,carbide ceramics,and novel carbon hybrids,this study aims to offer theoretical and technical guidance for the development of advanced high-temperature electromagnetic wave absorbers,thereby promoting their practical applications in aerospace and telecommunications.展开更多
Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challe...Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challenge owing to the intrinsic trade-off relationship.Herein,we utilized the in situ controllable reduction of graphene oxide(GO)within a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)(P(VDF-Tr FE-CFE))matrix to regulate the dielectric properties.The as-obtained composite exhibited a high relative dielectric constant of 1415coupled with a low loss tangent of 0.380 at 100 Hz.Experimental and theoretical studies indicate that the increased degree of electron conjugation and conductivity of the reduced GO(RGO)are responsible for the high-k.The constrained reduction degree of GO,combined with its homogeneous dispersion in the polymer matrix,effectively suppresses long-range charge carrier migration,thereby minimizing dielectric loss.This novel strategy could be successfully applied to both organic and aqueous systems.Furthermore,a high-performance flexible capacitive proximity sensor was exemplified by the optimization of both the dielectric layer and electrode pattern,exhibiting excellent sensitivity and stability.The fundamental mechanisms elucidated in this study provide crucial design principles for developing dielectric PMCs with tailored properties,thereby opening new avenues for advanced flexible electronic applications.展开更多
NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and...NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and energy storage efficiency(η).Herein,novel NaNbO_(3)-based ceramics,(1-x)[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–xCaTiO_(3),were created by adding CaTiO_(3) linear dielectric,aiming to improve their energy storage performance(ESP).The phase structure,microstructure,dielectric properties,energy storage and charge–discharge performances of the ceramics were methodically analyzed.All components of the ceramics exhibit a perovskite structure consisting of two phases:antiferroelectric P-phase(AFE P)and antiferroelectric R-phase(AFE R),with the AFE R phase increasing as x rises.All ceramic surfaces exhibit clear grain morphology.The resultant ceramics have an appropriate dielectric constant and a small dielectric loss,which are beneficial for improving breakdown field strength(E_(b)).Finally,at an E_(b) of 470 kV/cm,0.85[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–0.15CaTiO_(3) ceramic achieves optimal ESP:W_(rec)=3.9 J/cm^(3),η=72.49%.In addition,it has remarkable stability with temperature and frequency in energy storage and displays ultrafast speed in the charge–discharge process(t_(0.9)=27 ns).展开更多
Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric fo...Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.展开更多
Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received wides...Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.展开更多
The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic pr...The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic properties of cobalt ferrite is reported. X-ray diffraction patterns of the prepared samples confirm that the Bragg＇s peak belongs to a spinel cubic crystal structure. The lattice constant of cobalt ferrite increases with the increase in Mn content. The microstructural study is carried out by using the SEM technique and the average grain size continues to increase with increasing manganese content. AC conductivity analysis suggests that the conduction is due to small polaron hopping. DC electrical resistivity decreases with increasing temperature for a Col-xMnxFe204 system showing semiconducting behavior. The activation energy is found to be higher in the paramagnetic region than the ferromagnetic region. Curie temperature decreases with Mn substitution in the host ferrite system. Dielectric dispersion having Maxwell-Wagner-type interfacial polarization has been observed for cobalt ferrite samples. Magnetic properties have been studied by measuring M-H plots. The saturation and remanent magnetization increases with Mn substitution.展开更多
The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of SOFCs.This has stimulated a substantial materials research effort in developi...The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of SOFCs.This has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of SOFCs.In this context,for the first time,a dielectric material,CaCu_(3)Ti_(4)O_(12)(CCTO)is designed for LT-SOFCs electrolyte application in this study.Both individual CCTO and its heterostructure materials with a p-type Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ)(NCAL)semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550℃.The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm^(-2) and an open-circuit voltage(OCV)of 0.95 V at 550℃,while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm^(-2) along with a higher OCV over 1.0 V,which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting risk.It is found that these promising outcomes are due to the interplay of the dielectric material,its structure,and overall properties that led to improve electrochemical mechanism in CCTO–NCAL.Furthermore,density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–NCAL.Our study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.展开更多
A 4H-SiC superjunction(SJ)MOSFET(SJMOS)with integrated high-K gate dielectric and split gate(HKSG-SJMOS)is proposed in this paper.The key features of HKSG-SJMOS involve the utilization of high-K(HK)dielectric as the g...A 4H-SiC superjunction(SJ)MOSFET(SJMOS)with integrated high-K gate dielectric and split gate(HKSG-SJMOS)is proposed in this paper.The key features of HKSG-SJMOS involve the utilization of high-K(HK)dielectric as the gate dielectric,which surrounds the source-connected split gate(SG)and metal gate.The high-K gate dielectric optimizes the electric field distribution within the drift region,creating a low-resistance conductive channel.This enhancement leads to an increase in the breakdown voltage(BV)and a reduction in the specific on resistance(R_(on,sp)).The introduction of split gate surrounded by high-K dielectric reduces the gate-drain capacitance(C_(gd))and gate-drain charge(Q_(gd)),which improves the switching characteristics.The simulation results indicate that compared to conventional 4H-SiC SJMOS,the HKSG-SJMOS exhibits a 110.5%enhancement in figure of merit(FOM,FOM=BV^(2)/R_(on,sp)),a 93.6%reduction in the high frequency figure of merit(HFFOM)of R_(on,sp)·C_(gd),and reductions in turn-on loss(E_(on))and turn-off loss(E_(off))by 38.3%and 31.6%,respectively.Furthermore,the reverse recovery characteristics of HKSG-SJMOS has also discussed,revealing superior performance compared to conventional 4H-SiC SJMOS.展开更多
Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susce...Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susceptible to electromagnetic interference and changes in the surrounding medium,resulting in unstable signal acquisition.Capacitive sensor with excellent immunity to interference while maintaining flexibility is an urgent challenge.This study proposes an all-fiber anti-jamming capacitive pressure sensor that integrates liquid metal(LM)into a fiber-based dielectric layer.The combination of the LM and the fiber not only improves the dielectric properties of the dielectric layer but also reduces the Young's modulus of the fiber.The sensor has high interference immunity in various noise environments.Its all-fiber structure ensures lightweight,great air permeability and stretchability,whichmakes it a promising application in wearable electronic devices fields.展开更多
Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction...Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction loss in EMW-absorbing materials and charge transfer in HB remains to be fully understood.In this study,we developed a series of deep eutectic gels to fine-tune the quantity of HB by adjusting the molar ratio of choline chloride(ChCl)and ethylene glycol(EG).Owing to the unique properties of deep eutectic gels,the effects of magnetic loss and polarization loss on EMW attenuation can be disregarded.Our results indicate that the quantity of HB initially increases and then decreases with the introduction of EG,with HB-induced conductive loss following similar pat-terns.At a ChCl and EG molar ratio of 2.4,the gel labeled G22-CE2.4 exhibited the best EMW absorption performance,characterized by an effective absorption bandwidth of 8.50 GHz and a thickness of 2.54 mm.This superior performance is attributed to the synergistic ef-fects of excellent conductive loss and impedance matching generated by the optimal number of HB.This work elucidates the role of HB in dielectric loss for the first time and provides valuable insights into the optimal design of supramolecular polymer absorbers.展开更多
Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal ...Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal conductivity in polymers remains a challenge.In this work,we present a feasible strategy to integrate high electrical insulation and high thermal conductivity by bonding carbon quantum dots(CQDs)with the diamine monomer of polyetherimide(PEI).The CQDs with Coulomb blockade effect serve as traps for the migrating of electrons in the dielectrics,while the bonding networks formed by CQDs and PEI further deepen the traps and augment trap density.As a result,the hybrid dielectrics(PEI-NH_(2)-CQDs)exhibit nearly an order of magnitude higher electrical resistivity than that of pure PEI,leading to an 80%increase in discharge energy density with an energy efficiency of 90%at 200℃ compared to pure counterpart.Additionally,this all-organic dielectric achieves a significantly increased thermal conductivity of 0.65 W m^(-1) K^(-1) compared to 0.26 W m^(-1) K^(-1) of PEI,which supports its cyclic stability at elevated temperatures.We also demonstrate the kilogram-scale production of CQDs,synthesizing over 8 kg in a single batch,paving the way for large-scale production of reliable PEI-NH_(2)-CQDs dielectrics.展开更多
W-type barium-nickel ferrite(BaNi_(2)Fe_(16)O_(27))is a highly promising material for electromagnetic wave(EMW)absorption be-cause of its magnetic loss capability for EMW,low cost,large-scale production potential,high...W-type barium-nickel ferrite(BaNi_(2)Fe_(16)O_(27))is a highly promising material for electromagnetic wave(EMW)absorption be-cause of its magnetic loss capability for EMW,low cost,large-scale production potential,high-temperature resistance,and excellent chemical stability.However,the poor dielectric loss of magnetic ferrites hampers their utilization,hindering enhancement in their EMW-absorption performance.Developing efficient strategies that improve the EMW-absorption performance of ferrite is highly desired but re-mains challenging.Here,an efficient strategy substituting Ba^(2+)with rare earth La^(3+)in W-type ferrite was proposed for the preparation of novel La-substituted ferrites(Ba_(1-x)LaxNi_(2)Fe_(15.4)O_(27)).The influences of La^(3+)substitution on ferrites’EMW-absorption performance and the dissipative mechanism toward EMW were systematically explored and discussed.La^(3+)efficiently induced lattice defects,enhanced defect-induced polarization,and slightly reduced the ferrites’bandgap,enhancing the dielectric properties of the ferrites.La^(3+)also enhanced the ferromagnetic resonance loss and strengthened magnetic properties.These effects considerably improved the EMW-absorption perform-ance of Ba_(1-x)LaxNi_(2)Fe_(15.4)O_(27)compared with pure W-type ferrites.When x=0.2,the best EMW-absorption performance was achieved with a minimum reflection loss of-55.6 dB and effective absorption bandwidth(EAB)of 3.44 GHz.展开更多
Regulating lithium(Li)plating/stripping behavior in three-dimensional(3D)conductive scaffolds is critical to stabilizing Li metal batteries(LMBs).Surface protrusions and roughness in these scaffolds can induce uneven ...Regulating lithium(Li)plating/stripping behavior in three-dimensional(3D)conductive scaffolds is critical to stabilizing Li metal batteries(LMBs).Surface protrusions and roughness in these scaffolds can induce uneven distributions of the electric fields and ionic concentrations,forming“hot spots.”Hot spots may cause uncontrollable Li dendrites growth,presenting significant challenges to the cycle stability and safety of LMBs.To address these issues,we construct a Li ionic conductive-dielectric gradient bifunctional interlayer(ICDL)onto a 3D Li-injected graphene/carbon nanotube scaffold(LGCF)via in situ reaction of exfoliated hexagonal boron nitride(fhBN)and molten Li.Microscopic and spectroscopic analyses reveal that ICDL consists of fhBN-rich outer layer and inner layer enriched with Li_(3)N and Li-boron composites(Li-B).The outer layer utilizes dielectric properties to effectively homogenize the electric field,while the inner layer ensures high Li ion conductivity.Moreover,DFT calculations indicate that ICDL can effectively adsorb Li and decrease the Li diffusion barrier,promoting enhanced Li ion transport.The modulation of Li kinetics by ICDL increases the critical length of the Li nucleus,enabling suppression of Li dendrite growth.Attributing to these advantages,the ICDL-coated LGCF(ICDL@LGCF)demonstrates impressive long-term cycle performances in both symmetric cells and full cells.展开更多
文摘Barium titanate, BaTiO3 (BTO) is the most common ferro electric material, which is used to manufacture electronic components such as multilayer capacitors, positive temperature coefficient thermistors, piezo electric transdures, and ferro electric memory. Zr doped barium magnesium titanate (Ba0.9Mg1.0)(ZrxTi1-x)O3 (with x = 0.10, 0.20, 0.40 (BMZT 10, BMZT 20 and BMZT 40) perovskite is prepared by conventional solid state reaction method. The starting raw materials were BaCO3, TiO2, MgO and ZrO2. The XRD study at room temperature suggests that these have cubic and tetragonal symmetry phases. The behavior of the measured dielectric permittivity and dielectric loss with temperature and frequency reveals that the materials undergo a diffuse para-ferroelectric phase transition and are of the relaxor type. The crystal structure, surface morphology and dielectric properties of Zr and Mg doped barium titanate ceramics were investigated. Zr4+ and Mg2+ ions have entered the unit cell maintaining the perovskite structure of solid solution without the evidence of any additional phase when Mg content is 0.1 mole% and the Zr content is 0.10, 0.20 and 0.40 mole%.
基金Project supported by the Natural Science Foundation of zhejiang Provincethe Chinese Postdoctoral Foundation
文摘The spectra of the dielectrical constant and dielectrical loss in three nanostructured a-Fe2O3 samples at different annealed temperatures are measured by using ac LRC method. The relaxation times of polarization and the conductance are calculated by means of the Debye mechanism and the interface effects in two kinds of polarization processes with two different relaxation times are proposed.
文摘A new,cost-effective porous polymer composite was developed by reinforcing polypropylene(PP)with cenosphere particles.This study investigates how the composite’s dielectric properties are affected by their porosity.Dielectric constant(ε′)measurements were taken over a range of frequencies at roomtemperature.A theoreticalmodel was developed to explain the electrical conductivity of the porous PP/cenosphere composites.The study thoroughly examined how the inclusion of cenosphere particles influenced key electrical parameters,including dielectric constant,dissipation factor(tanδ),DC(direct current)conductivity,and AC(alternating current)conductivity.The results revealed that increasing the cenosphere content caused a decrease in the dielectric constant,while the dissipation factor increased.The developed porous PP/cenosphere composite exhibits a unique balance of low dielectric constant,lightweight structure making it suitable for several practical applications.Its low dielectric constant and reduced DC conductivity make it an excellent candidate for electronic packaging,insulating layers,and high-frequency components,where minimal energy loss and signal interference are required.The lightweight nature of the cenosphere-reinforced structure also suggests potential use in aerospace and automotive industries for lightweight insulation panels or structural components.Furthermore,its cost-effectiveness and tunable porosity could enable applications in microwave substrates,radar-absorbing materials,and energy-efficient building materials where dielectric control and weight reduction are critical.Additionally,DC conductivity was found to decline with higher cenosphere concentrations.The theoretical model was in good agreement with the experimental data.
基金financially supported by the National Key R&D Program of China(No.2023YFB3812400)the National Natural Science Foundation of China(No.51890871)the GJYC Program of Guangzhou(No.2024D02J0004)。
文摘The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.
基金supported by the Open Foundation of Hainan International Joint Research Center of Marine Advanced Photoelectric Functional Materials(2025MAPFM01)Fundação para a Ciência e Tecnologia(FCT),Portugal,for the Centro de Química Estrutural,Institute of Molecular Sciences projects UIDB/00100。
文摘Triboelectric nanogenerators(TENGs)show promise for sustainable energy harvesting;however,their development faces challenges due to the limited performance of traditional polymers,such as PDMS and PTFE.This drives interest in metal-organic frameworks(MOFs),which offer high surface area,tunable porosity,and customizable chemical functionality that can help overcome these limitations.In this review,we thoroughly analyze the application of MOFs in TENGs by exploring structural design strategies,ligand modifications,and layer engineering,as well as assessing performance results from recent studies.We highlight essential findings indicating that electron-withdrawing groups,such as-NO_(2),-F,and-SO_(3)H,notably increase tribonegativity.Additionally,doping with conductive nanomaterials and employing machine learning approaches further boost power density.Finally,we propose that future advancements in this area should focus on addressing environmental sensitivity,mechanical brittleness,and synthesis complexity through molecular-level tailoring combined with scalable device engineering,ultimately paving the way for durable,high-efficiency MOF-based TENGs.
文摘As circuit feature sizes approach the nanoscale,traditional Copper(Cu)interconnects face significant hurdles posed by rising resistance-capacitance(RC)delay,electromigration,and high power dissipation.These limitations impose constraints on the scalability and reliability of future semiconductor technologies.Our paper describes the new Vertical multilayer Aluminium Boron Nitride Nanoribbon(AlBN)interconnect structure,integrated with Density functional theory(DFT)using first-principles calculations.This study explores AlBN-based nanostructures with doping of 1Cu,2Cu,1Fe(Iron),and 2Fe for the application of Very Large Scale Integration(VLSI)interconnects.The AlBN structure utilized the advantages of vertical multilayer interconnects to both reduce the RC delay while enhancing signal integrity.Key parameters like Fermi energy,bandgap,binding energy,conduction channels,quantum resistance,and RC delay were analyzed.Through modeling and large-scale simulation,the structural,electronic,and stability attributes of the AlBN interconnects are analyzed,and the results illustrate considerable improvements in signal propagation against Cu interconnect structures.These findings confirm the tunable,high-performance nature of AlBN-2Fe,making it a promising candidate for future high-speed,low-power VLSI interconnect technologies.We demonstrated an advanced energy-efficient interconnect that can be easily scaled for future nanoscale VLSI circuit design and gives rise to a next generation of viable interconnect technology for high-capacity,high-speed,reliable semiconductor technology.
基金financially supported by the Hubei Key Laboratory of Pollutant Analysis&Reuse Technology(No.PA230102)。
文摘Polyurethane elastomers exhibit high dielectric constants owing to their polar groups,and can be used as energy storage capacitors.Energy storage depends not only on the dielectric constant but also on the dielectric loss.However,the relationship between chain structure and dielectric properties is not yet clear.Ketal-containing crosslinked polyurethane elastomers were prepared using cyclic ketal diol as a chain extender.The effect of the soft segment length on the dielectric properties and energy storage was investigated.The cause of the change in the dipolar polarization with the soft segment length was analyzed.As the soft segment length increased,the hard-soft hydrogen bonding decreased,whereas the hard-hard hydrogen bonding increased.Under the action of an electric field,the polar bonds in the ketal-containing polyurethane elastomer overcome the hydrogen bonding between hard-soft segments to produce polarization;meanwhile,they also experience crankshaft motions to generate polarization.The former has a relatively high relaxation activation energy of approximately 10-20 k J·mol^(-1),resulting in a large dielectric loss.The latter has a relatively low relaxation activation energy,approximately 0.7-1.7 kJ·mol^(-1),leading to low dielectric loss.As a result,the dielectric constant showed a decreasing trend,and the dielectric loss gradually decreased.This study provides a theoretical foundation for improving the dielectric properties of polyurethane elastomers.
基金supported by the National Natural Science Foundation of China(52572086 and 52502371)the Natural Science Foundation of Henan(242300421010)+2 种基金Scientific and Technological Innovation Talents in Colleges and Universities in Henan Province(22HASTIT001)the Henan Province Natural Science Foundation Outstanding Youth Fund Project(242300421009)the Henan Province science and technology research project(252102320354and 252102230037)。
文摘The demand for high-temperature electromagnetic wave absorption(EWA)materials has significantly increased alongside advancements in aerospace and communication technologies.Although traditional magnetic absorbers,such as ferrites and metal powders,show excellent magnetic loss performance at room temperature,they have significant limitations in harsh environments due to their high density,low Curie temperature,and susceptibility to oxidation.In contrast,carbon-containing materials have emerged as promising candidates for high-temperature EWA applications,owing to their high melting point,low density,tunable dielectric loss mechanisms,and superior thermal stability.Unlike magnetic materials,carbon-based systems primarily dissipate electromagnetic energy through conductance loss,dipole polarization,and interfacial polarization,thereby avoiding performance degradation at elevated temperatures.However,several critical challenges remain,including insufficient oxidation resistance,mechanical reliability issues,and the need for stable impedance matching.To address these limitations,recent strategies such as defect engineering,heterointerface construction,and metamaterial design have been proposed to enhance thermal stability and functional performance.This review provides a systematic summary of recent advances in carbon-containing absorbers,with a focus on dielectric loss mechanisms,optimization strategies,and multiscale structural design principles.By elucidating the structure–property relationships of carbon materials,carbide ceramics,and novel carbon hybrids,this study aims to offer theoretical and technical guidance for the development of advanced high-temperature electromagnetic wave absorbers,thereby promoting their practical applications in aerospace and telecommunications.
基金financially supported by the Innovation and Technology Commission of the Hong Kong SAR Government(No.MRP/020/21)Hong Kong Polytechnic University(No.847A)+1 种基金RI-Wear Seed Fund of Poly U(1-CD8J)Start-up Fund of Poly U(1-BD49)。
文摘Polymer matrix composites with high dielectric constants and low dielectric losses are in high demand for flexible electronics.However,simultaneously satisfying these requirements poses a significant scientific challenge owing to the intrinsic trade-off relationship.Herein,we utilized the in situ controllable reduction of graphene oxide(GO)within a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene)(P(VDF-Tr FE-CFE))matrix to regulate the dielectric properties.The as-obtained composite exhibited a high relative dielectric constant of 1415coupled with a low loss tangent of 0.380 at 100 Hz.Experimental and theoretical studies indicate that the increased degree of electron conjugation and conductivity of the reduced GO(RGO)are responsible for the high-k.The constrained reduction degree of GO,combined with its homogeneous dispersion in the polymer matrix,effectively suppresses long-range charge carrier migration,thereby minimizing dielectric loss.This novel strategy could be successfully applied to both organic and aqueous systems.Furthermore,a high-performance flexible capacitive proximity sensor was exemplified by the optimization of both the dielectric layer and electrode pattern,exhibiting excellent sensitivity and stability.The fundamental mechanisms elucidated in this study provide crucial design principles for developing dielectric PMCs with tailored properties,thereby opening new avenues for advanced flexible electronic applications.
基金Project supported by the Natural Science Foundation of Anhui Provincial Education Department(Grant No.KJ2019A0054)。
文摘NaNbO_(3)-based lead-free dielectric ceramics possess significant application prospects in the field of dielectric capacitors.However,their development is hindered by low recoverable energy storage density(W_(rec))and energy storage efficiency(η).Herein,novel NaNbO_(3)-based ceramics,(1-x)[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–xCaTiO_(3),were created by adding CaTiO_(3) linear dielectric,aiming to improve their energy storage performance(ESP).The phase structure,microstructure,dielectric properties,energy storage and charge–discharge performances of the ceramics were methodically analyzed.All components of the ceramics exhibit a perovskite structure consisting of two phases:antiferroelectric P-phase(AFE P)and antiferroelectric R-phase(AFE R),with the AFE R phase increasing as x rises.All ceramic surfaces exhibit clear grain morphology.The resultant ceramics have an appropriate dielectric constant and a small dielectric loss,which are beneficial for improving breakdown field strength(E_(b)).Finally,at an E_(b) of 470 kV/cm,0.85[0.7Na_(0.97)Sm_(0.01)NbO_(3)–0.3(Sr_(0.7)Bi_(0.2))(Ti_(0.8)Zr_(0.2))O_(3)]–0.15CaTiO_(3) ceramic achieves optimal ESP:W_(rec)=3.9 J/cm^(3),η=72.49%.In addition,it has remarkable stability with temperature and frequency in energy storage and displays ultrafast speed in the charge–discharge process(t_(0.9)=27 ns).
基金supported by the Samsung Electronics Co.,Ltd.(ISO230414-05954-01)Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(NRF2021R1A6A1A03039981)+2 种基金the Korea Institute for Advancement of Technology(KIAT)Grant,funded by the Korea Government(MOTIE)(P0023703,HRD Program for Industrial Innovation)The computations were performed at the Korea Institute of Science and Technology Information(KISTI)National Supercomputing Center(KSC-2024-CRE-0316)the UNIST Supercomputing Center。
文摘Atomic layer deposition(ALD)is extensively used to fabricate doped dielectrics due to its ability to deposit conformal films with atomic-scale thickness control.Al-doped TiO_(2)(ATO)is a promising high-k dielectric for dynamic random access memory(DRAM)applications,offering a high dielectric constant with a remarkable leakage-lowering effect by Al acceptor doping.However,ATO fabrication via conventional supercycle-based ALD suffers from severe crystallinity loss during the growth of TiO_(2) upon Al doping owing to the dopant-induced lattice disorder.In addition,Al doping cannot reduce any inherent O vacancies(V_(O))of TiO_(2),although the original purpose of doping was to address the n-type nature caused by V_(O).To resolve these limitations,we propose a single-step,in-situ Ar/O_(2) post-doping plasma(PDP)process immediately after the Al dopant incorporation.Using the PDP process,simultaneous atomic-scale dopant migration-mediated crystallization and V_(O) annihilation were successfully initiated.Thus,the surface concentration of the dopant decreased,reducing the dopant-induced lattice distortion,while promoting the highly crystallized seed layer-like surface.Consequently,strong rutile-phase recovery was accompanied by enhanced lattice-matched growth.In addition,the PDP process significantly lowers the V_(O)-to-lattice oxygen ratio by facilitating the recombination between reactive O species and V_(O),increasing the corresponding 0.4 e V of conduction band offset(CBO).Despite the common trade-off between the dielectric constant and leakage,the Pt/PDP-ATO/Ru capacitor exhibited a simultaneous 30%increase in dielectric constant and up to a 1.6-order reduction in leakage current density.
基金supported by the National Key Basic Research Program of China (2022YFA1402904)Basic Research Project of Shanghai Science and Technology Innovation Action (grant number 24CL2900900)the National Natural Science Foundation of China (grant number 61904034)
文摘Innovative use of HfO_(2)-based high-dielectric-permittivity materials could enable their integration into few-nanometre-scale devices for storing substantial quantities of electrical charges,which have received widespread applications in high-storage-density dynamic random access memory and energy-efficient complementary metal-oxide-semiconductor devices.During bipolar high electric-field cycling in numbers close to dielectric breakdown,the dielectric permittivity suddenly increases by 30 times after oxygen-vacancy ordering and ferroelectric-to-nonferroelectric phase transition of near-edge plasma-treated Hf_(0.5)Zr_(0.5)O_(2) thin-film capacitors.Here we report a much higher dielectric permittivity of 1466 during downscaling of the capacitor into the diameter of 3.85μm when the ferroelectricity suddenly disappears without high-field cycling.The stored charge density is as high as 183μC cm^(−2) at an operating voltage/time of 1.2 V/50 ns at cycle numbers of more than 10^(12) without inducing dielectric breakdown.The study of synchrotron X-ray micro-diffraction patterns show missing of a mixed tetragonal phase.The image of electron energy loss spectroscopy shows the preferred oxygen-vacancy accumulation at the regions near top/bottom electrodes as well as grain boundaries.The ultrahigh dielectric-permittivity material enables high-density integration of extremely scaled logic and memory devices in the future.
基金the UGC-DSA-I, DSTPURSE and DST-FIST-II programs for financial support
文摘The C01-xMnxFez04 （0 ≤ x 〈-5 0.5） ferrite system is synthesized by using an auto combustion technique using metal nitrates. The influence of Mn substitution on the structural, electrical, impedance and magnetic properties of cobalt ferrite is reported. X-ray diffraction patterns of the prepared samples confirm that the Bragg＇s peak belongs to a spinel cubic crystal structure. The lattice constant of cobalt ferrite increases with the increase in Mn content. The microstructural study is carried out by using the SEM technique and the average grain size continues to increase with increasing manganese content. AC conductivity analysis suggests that the conduction is due to small polaron hopping. DC electrical resistivity decreases with increasing temperature for a Col-xMnxFe204 system showing semiconducting behavior. The activation energy is found to be higher in the paramagnetic region than the ferromagnetic region. Curie temperature decreases with Mn substitution in the host ferrite system. Dielectric dispersion having Maxwell-Wagner-type interfacial polarization has been observed for cobalt ferrite samples. Magnetic properties have been studied by measuring M-H plots. The saturation and remanent magnetization increases with Mn substitution.
基金National Natural Science Foundation of China(NSFC)supported this work under Grant No.32250410309,11674086,51736006,and 51772080funding from Science and Technology Department of Jiangsu Province under Grant No.BE2022029Shenzhen University under Grant No.86902/000248 also supported part of this work.
文摘The development of low-temperature solid oxide fuel cells(LT-SOFCs)is of significant importance for realizing the widespread application of SOFCs.This has stimulated a substantial materials research effort in developing high oxide-ion conductivity in the electrolyte layer of SOFCs.In this context,for the first time,a dielectric material,CaCu_(3)Ti_(4)O_(12)(CCTO)is designed for LT-SOFCs electrolyte application in this study.Both individual CCTO and its heterostructure materials with a p-type Ni_(0.8)Co_(0.15)Al_(0.05)LiO_(2−δ)(NCAL)semiconductor are evaluated as alternative electrolytes in LT-SOFC at 450–550℃.The single cell with the individual CCTO electrolyte exhibits a power output of approximately 263 mW cm^(-2) and an open-circuit voltage(OCV)of 0.95 V at 550℃,while the cell with the CCTO–NCAL heterostructure electrolyte capably delivers an improved power output of approximately 605 mW cm^(-2) along with a higher OCV over 1.0 V,which indicates the introduction of high hole-conducting NCAL into the CCTO could enhance the cell performance rather than inducing any potential short-circuiting risk.It is found that these promising outcomes are due to the interplay of the dielectric material,its structure,and overall properties that led to improve electrochemical mechanism in CCTO–NCAL.Furthermore,density functional theory calculations provide the detailed information about the electronic and structural properties of the CCTO and NCAL and their heterostructure CCTO–NCAL.Our study thus provides a new approach for developing new advanced electrolytes for LT-SOFCs.
基金supported by the National Natural Science Foundation of China(Grant Nos.62074080 and U23B2042)in part by the Natural Science Foundation of Jiangsu Province(Grant No.BK20211104)in part by the Jiangsu Provincial Key Research and Development Program(Grant No.BE2022126)。
文摘A 4H-SiC superjunction(SJ)MOSFET(SJMOS)with integrated high-K gate dielectric and split gate(HKSG-SJMOS)is proposed in this paper.The key features of HKSG-SJMOS involve the utilization of high-K(HK)dielectric as the gate dielectric,which surrounds the source-connected split gate(SG)and metal gate.The high-K gate dielectric optimizes the electric field distribution within the drift region,creating a low-resistance conductive channel.This enhancement leads to an increase in the breakdown voltage(BV)and a reduction in the specific on resistance(R_(on,sp)).The introduction of split gate surrounded by high-K dielectric reduces the gate-drain capacitance(C_(gd))and gate-drain charge(Q_(gd)),which improves the switching characteristics.The simulation results indicate that compared to conventional 4H-SiC SJMOS,the HKSG-SJMOS exhibits a 110.5%enhancement in figure of merit(FOM,FOM=BV^(2)/R_(on,sp)),a 93.6%reduction in the high frequency figure of merit(HFFOM)of R_(on,sp)·C_(gd),and reductions in turn-on loss(E_(on))and turn-off loss(E_(off))by 38.3%and 31.6%,respectively.Furthermore,the reverse recovery characteristics of HKSG-SJMOS has also discussed,revealing superior performance compared to conventional 4H-SiC SJMOS.
基金financially supported by the National Natural Science Foundation of China(Nos.U20A20166,52371202,52125205,52250398,52192614 and 52003101)the National Key R&D Program of China(No.2021YFB3200300)+2 种基金the Natural Science Foundation of Beijing Municipality(No.2222088)Shenzhen Science and Technology Program(No.KQTD20170810105439418)the Fundamental Research Funds for the Central Universities
文摘Capacitive pressure sensors have a promising application in the field of wearable electronic devices due to their excellent electrical properties.Owing to the complexity of the environment,capacitive sensors are susceptible to electromagnetic interference and changes in the surrounding medium,resulting in unstable signal acquisition.Capacitive sensor with excellent immunity to interference while maintaining flexibility is an urgent challenge.This study proposes an all-fiber anti-jamming capacitive pressure sensor that integrates liquid metal(LM)into a fiber-based dielectric layer.The combination of the LM and the fiber not only improves the dielectric properties of the dielectric layer but also reduces the Young's modulus of the fiber.The sensor has high interference immunity in various noise environments.Its all-fiber structure ensures lightweight,great air permeability and stretchability,whichmakes it a promising application in wearable electronic devices fields.
基金supported by the National Nat-ural Science Foundation of China(Nos.51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities,China(Nos.3102018zy045 and 3102019AX11)+2 种基金the Guangdong Basic and Applied Basic Research Foundation,China(No.2024A1515010298)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118)the Key Laboratory of Icing and Anti/De-icing of CARDC(No.IADL20220401).
文摘Gels and conductive polymer composites,including hydrogen bonds(HBs),have emerged as promising materials for electro-magnetic wave(EMW)absorption across various applications.However,the relationship between conduction loss in EMW-absorbing materials and charge transfer in HB remains to be fully understood.In this study,we developed a series of deep eutectic gels to fine-tune the quantity of HB by adjusting the molar ratio of choline chloride(ChCl)and ethylene glycol(EG).Owing to the unique properties of deep eutectic gels,the effects of magnetic loss and polarization loss on EMW attenuation can be disregarded.Our results indicate that the quantity of HB initially increases and then decreases with the introduction of EG,with HB-induced conductive loss following similar pat-terns.At a ChCl and EG molar ratio of 2.4,the gel labeled G22-CE2.4 exhibited the best EMW absorption performance,characterized by an effective absorption bandwidth of 8.50 GHz and a thickness of 2.54 mm.This superior performance is attributed to the synergistic ef-fects of excellent conductive loss and impedance matching generated by the optimal number of HB.This work elucidates the role of HB in dielectric loss for the first time and provides valuable insights into the optimal design of supramolecular polymer absorbers.
基金supported by the National Natural Science Foundation of China(52172265)Excellent Youth Science Foundation of Hunan Province(2022JJ20067)+1 种基金The Science and Technology Innovation Program of Hunan Province(2022RC1074)Central South University Innovation-Driven Research Program(2023CXQD010).
文摘Polymer dielectrics possessing excellent electrical insulation and high thermal conductivity are pivotal for dielectric capacitors at elevated temperatures.However,the integration of electrical insulation and thermal conductivity in polymers remains a challenge.In this work,we present a feasible strategy to integrate high electrical insulation and high thermal conductivity by bonding carbon quantum dots(CQDs)with the diamine monomer of polyetherimide(PEI).The CQDs with Coulomb blockade effect serve as traps for the migrating of electrons in the dielectrics,while the bonding networks formed by CQDs and PEI further deepen the traps and augment trap density.As a result,the hybrid dielectrics(PEI-NH_(2)-CQDs)exhibit nearly an order of magnitude higher electrical resistivity than that of pure PEI,leading to an 80%increase in discharge energy density with an energy efficiency of 90%at 200℃ compared to pure counterpart.Additionally,this all-organic dielectric achieves a significantly increased thermal conductivity of 0.65 W m^(-1) K^(-1) compared to 0.26 W m^(-1) K^(-1) of PEI,which supports its cyclic stability at elevated temperatures.We also demonstrate the kilogram-scale production of CQDs,synthesizing over 8 kg in a single batch,paving the way for large-scale production of reliable PEI-NH_(2)-CQDs dielectrics.
基金financially supported by the National Key R&D Program of China(No.2021YFB3502500)the Natur-al Science Foundation of Shandong Province,China(No.2022HYYQ-014)+5 种基金the“20 Clauses about Colleges and Uni-versities(new)”(Independent Training of Innovation Team)Program of Jinan,China(No.2021GXRC036)the Provin-cial Key Research and Development Program of Shandong,China(No.2021ZLGX01)the National Natural Science Foundation of China(No.22375115)the Joint Laboratory project of Electromagnetic Structure Technology(No.637-2022-70-F-037)the Discipline Construction Expenditure for Distinguished Young Scholars of Shandong University,China(No.31370089963141)the Qilu Young Scholar Program of Shandong University,China(No.31370082163127).
文摘W-type barium-nickel ferrite(BaNi_(2)Fe_(16)O_(27))is a highly promising material for electromagnetic wave(EMW)absorption be-cause of its magnetic loss capability for EMW,low cost,large-scale production potential,high-temperature resistance,and excellent chemical stability.However,the poor dielectric loss of magnetic ferrites hampers their utilization,hindering enhancement in their EMW-absorption performance.Developing efficient strategies that improve the EMW-absorption performance of ferrite is highly desired but re-mains challenging.Here,an efficient strategy substituting Ba^(2+)with rare earth La^(3+)in W-type ferrite was proposed for the preparation of novel La-substituted ferrites(Ba_(1-x)LaxNi_(2)Fe_(15.4)O_(27)).The influences of La^(3+)substitution on ferrites’EMW-absorption performance and the dissipative mechanism toward EMW were systematically explored and discussed.La^(3+)efficiently induced lattice defects,enhanced defect-induced polarization,and slightly reduced the ferrites’bandgap,enhancing the dielectric properties of the ferrites.La^(3+)also enhanced the ferromagnetic resonance loss and strengthened magnetic properties.These effects considerably improved the EMW-absorption perform-ance of Ba_(1-x)LaxNi_(2)Fe_(15.4)O_(27)compared with pure W-type ferrites.When x=0.2,the best EMW-absorption performance was achieved with a minimum reflection loss of-55.6 dB and effective absorption bandwidth(EAB)of 3.44 GHz.
基金the financial support from the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2023R1A2C2007699 and 2022R1A6A1A0306303912)the Nano Material Technology Development Program through the NRF funded by the Ministry of Science and ICT (NRF-2015M3A7B6027970)the Technology Innovation Program by the Ministry of Trade, Industry & Energy (RS-202300236794)
文摘Regulating lithium(Li)plating/stripping behavior in three-dimensional(3D)conductive scaffolds is critical to stabilizing Li metal batteries(LMBs).Surface protrusions and roughness in these scaffolds can induce uneven distributions of the electric fields and ionic concentrations,forming“hot spots.”Hot spots may cause uncontrollable Li dendrites growth,presenting significant challenges to the cycle stability and safety of LMBs.To address these issues,we construct a Li ionic conductive-dielectric gradient bifunctional interlayer(ICDL)onto a 3D Li-injected graphene/carbon nanotube scaffold(LGCF)via in situ reaction of exfoliated hexagonal boron nitride(fhBN)and molten Li.Microscopic and spectroscopic analyses reveal that ICDL consists of fhBN-rich outer layer and inner layer enriched with Li_(3)N and Li-boron composites(Li-B).The outer layer utilizes dielectric properties to effectively homogenize the electric field,while the inner layer ensures high Li ion conductivity.Moreover,DFT calculations indicate that ICDL can effectively adsorb Li and decrease the Li diffusion barrier,promoting enhanced Li ion transport.The modulation of Li kinetics by ICDL increases the critical length of the Li nucleus,enabling suppression of Li dendrite growth.Attributing to these advantages,the ICDL-coated LGCF(ICDL@LGCF)demonstrates impressive long-term cycle performances in both symmetric cells and full cells.
