Lithium metal(LM)is a promising anode for next-generation batteries due to its high theoretical capacity and low electrode potential.Nonetheless,side reactions,volume change,and unwanted lithium dendrite growth seriou...Lithium metal(LM)is a promising anode for next-generation batteries due to its high theoretical capacity and low electrode potential.Nonetheless,side reactions,volume change,and unwanted lithium dendrite growth seriously limit the practical application of LM.Herein,with the aid of a hard template approach,a novel lithiophilic CoF_(2)-carbon hollow sphere(CoF_(2)@C-HS)composite material is successfully prepared via a facile in-situ fluorination and etching strategy.The lithiophilic CoF_(2) acts as nucleation sites to reduce nucleation overpotential as well as induces the spatial Li deposition and the formation of LiFrich solid electrolyte interphase(SEI),and the hollow carbon matrix can enhance the electrical conductivity and offer free space for LM deposition.Theoretical simulations reveal that the synergistic effect of lithiophilic CoF_(2) and hollow carbon matrix homogenizes the electric field distribution and Li~+flux.Benefiting from these advantages,the CoF_(2)@C-HS-modified copper substrate electrode delivers an enhanced Coulombic efficiency(CE)of 93.7%for 280 cycles at 1 mA cm^(-2)and 1 mA h cm^(-2).The symmetrical cell using CoF_(2)@C-HS can stably cycle more than 1800 h with a low voltage hysteresis of 11 mV at a current density of 0.5 MA cm^(-2)and an areal capacity of 0.5 mA h cm^(-2).Moreover,the Li@CoF_(2)@C-HS composite anode enables more than 300 stable cycles at 1 C with a capacity retention of 95%in LiFePO_(4)-based full cell and 110 stable cycles at 1 C in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)-based highvoltage full cell.This work might shed a new light on designing lithiophilic hosts to spatially confine LM deposition,realizing dendrite-free LM anodes and the practical applications of LM batteries.展开更多
Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy density.Considering the structural des...Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy density.Considering the structural design and electrical properties of ferroelectric capacitor,it is still a challenge to ffnd out the optimal energy storage of ferroelectric ceramics during the phase-transition process of amorphous/nanocrystalline and polycrystalline.In this work,a ffnite element model suitable for the multiphase ceramic system is constructed based on the phase ffeld breakdown theory.The nonlinear coupling relationship of multiple physical ffelds between multiphase ceramics was taken into account in this model.The basic structures of multiphase ceramics are generated by using the Voronoi diagram construction method.The speciffed structure of multiphase ceramics in the phase-transition process of amorphous/nanocrystalline and polycrystalline was further obtained through the grain boundary diffusion equation.The simulation results show that the multiphase ceramics have an optimal energy storage in the process of amorphous polycrystalline transformation,and the energy storage density reaches the maximum when the crystallinity is 13.96%and the volume fraction of grain is 2.08%.It provides a research plan and idea for revealing the correlation between microstructure and breakdown characteristics of multiphase ceramics.This simulation model realizes the nonlinear coupling of the multiphase ceramic mesoscopic structure and the phase ffeld breakdown.It provides a reference scheme for the structural design and performance optimization of ferroelectric ceramics.展开更多
Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challeng...Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene.Herein,phosphorylated MXene/polypropylene(PP)composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine(PEI)and hot-pressing.The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates.Upon hot-pressing,melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases.The composites show significantly improved thermal stability and flame retardancy relative to pure PP,with a low total heat release(THR)of 3.7 kJ/g and a heat release rate(HRR)of 50.0 W/g,which are reduced by 78%and 87%,respectively.In addition,the composites exhibit a high electrical conductivity of~36,700 S/m and an EMI shielding performance of~90 d B over the whole frequency range of 8–12 GHz with a thickness of~400μm.The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments.展开更多
Electron,optical,and scanning probe microscopy methods are generating ever increasing volume of image data containing information on atomic and mesoscale structures and functionalities.This necessitates the developmen...Electron,optical,and scanning probe microscopy methods are generating ever increasing volume of image data containing information on atomic and mesoscale structures and functionalities.This necessitates the development of themachine learning methods for discovery of physical and chemical phenomena from the data,such as manifestations of symmetry breaking phenomena in electron and scanning tunneling microscopy images,or variability of the nanoparticles.Variational autoencoders(VAEs)are emerging as a powerful paradigm for the unsupervised data analysis,allowing to disentangle the factors of variability and discover optimal parsimonious representation.Here,we summarize recent developments in VAEs,covering the basic principles and intuition behind the VAEs.展开更多
Optimization of experimental materials synthesis and characterization through active learning methods has been growing over the last decade,with examples ranging from measurements of diffraction on combinatorial alloy...Optimization of experimental materials synthesis and characterization through active learning methods has been growing over the last decade,with examples ranging from measurements of diffraction on combinatorial alloys at synchrotrons,to searches through chemical space with automated synthesis robots for perovskites.In virtually all cases,the target property of interest for optimization is defined a priori with the ability to shift the trajectory of the optimization based on human-identified findings during the experiment is lacking.Thus,to highlight the best of both human operators and AI-driven experiments,here we present the development of a human–AI collaborated experimental workflow,via a Bayesian optimized active recommender system(BOARS),to shape targets on the fly with human real-time feedback.Here,the human guidance overpowers AI at early iteration when prior knowledge(uncertainty)is minimal(higher),while the AI overpowers the human during later iterations to accelerate the process with the human-assessed goal.We showcase examples of this framework applied to pre-acquired piezoresponse force spectroscopy of a ferroelectric thin film,and in real-time on an atomic force microscope,with human assessment to find symmetric hysteresis loops.It is found that such features appear more affected by subsurface defects than the local domain structure.This work shows the utility of human–AI approaches for curiosity driven exploration of systems across experimental domains.展开更多
Environmentally friendly lead-free ceramics capacitors,with outstanding power density,rapid charging/discharging rate,and superior stability,have been receiving increasing attention of late for their ability to meet t...Environmentally friendly lead-free ceramics capacitors,with outstanding power density,rapid charging/discharging rate,and superior stability,have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption systems.However,the relatively low energy storage capability must be urgently overcome.Herein,this work reports on leadfree SrTi_(0.875)Nb_(0.1)O_(3)(STN)replacement of(Bi_(0.47)La_(0.03)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)(BLNBT)ferroelectric ceramics with excellent energy storage performance.Improving relaxor behaviour and breakdown strength(Eb),decreasing grain size,and mitigating large polarization difference are conductive to the enhancement of comprehensive energy storage performances.The phase-field simulation methods are further analysized evolution process of electrical tree in the experimental breakdown.In particular,the 0.70BLNBT-0.30STN ceramic exhibit a large discharged energy density of 4.2 J/cm^(3) with an efficiency of 89.3%at room temperature under electric field of 380 kV/cm.Additionally,for practical applications,the BLNBT-based ceramics achieve a high power density(~62.3 MW/cm^(3))and fast discharged time(~148.8 ns)over broad temperature range(20-200℃).Therefore,this work can provide a simple and effective guideline paradigm for acquiring high-performance dielectric materials in low-consumption systems operating in a wide range of temperatures and long-term operations.展开更多
As a promising photovoltaic technology, perovskite solar cells(pero-SCs) have developed rapidly over the past few years and the highest power conversion efficiency is beyond 25%. Nowadays, the planar structure is univ...As a promising photovoltaic technology, perovskite solar cells(pero-SCs) have developed rapidly over the past few years and the highest power conversion efficiency is beyond 25%. Nowadays, the planar structure is universally popular in pero-SCs due to the simple processing technology and low-temperature preparation.Electron transport layer(ETL) is verified to play a vital role in the device performance of planar pero-SCs. Particularly, the metal oxide(MO) ETL with low-cost, superb versatility, and excellent optoelectronic properties has been widely studied. This review mainly focuses on recent developments in the use of low-temperature-processed MO ETLs for planar pero-SCs. The optical and electronic properties of widely used MO materials of TiO_(2), ZnO, and SnO_(2), as well as the optimizations of these MO ETLs are briefly introduced. The commonly used methods for depositing MO ETLs are also discussed. Then, the applications of different MO ETLs on pero-SCs are reviewed.Finally, the challenge and future research of MO-based ETLs toward practical application of efficient planar peroSCs are proposed.展开更多
Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective...Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective in PLA, but their high addition loading usually decreases the mechanical strength of the PLA bulk. For polyphosphoramides, despite high fire-retardant efficiency, their chemical synthesis often generates chemical wastes as byproducts. Herein, we report an atom-economic and highly efficient oligomeric P/N fire retardant (APN) prepared using a mild Michael addition polymerization with no byproducts. Using only 3 wt% APN, the resulting PLA exhibits desired fire retardancy including a UL-94 V-0 rating and a limiting oxygen index of 37.6%. Furthermore, the toughness of the fire-retardant PLA increases by 85% compared to pure PLA, with both tensile strength and thermal stability preserved. This work offers an atom-economic strategy for synthesizing highly efficient P/N fire retardants for use in the creation of fire-resistant PLA with robust mechanical properties.展开更多
The development of earth-abundant-metal-based electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction(HER)is crucial for the clean and renewable energy application.Herein,we repor...The development of earth-abundant-metal-based electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction(HER)is crucial for the clean and renewable energy application.Herein,we report a molten-salt method to synthesize Co-doped CaMn_(3)O_(6)(CMO)nanowires(NWs)as effective electrocatalyst for HER.The as-obtained CaMn_(3-x)Co_(x)O_(6)(CMCO)exhibits a small onset overpotential of 70 mV,a required overpotential of 140 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 39 mV·dec^(-1)in 0.1 M HClO_(4),and a satisfying long-term stability.Experimental characterizations combined with density functional theory(DFT)calculations demonstrate that the obtained HER performance can be attributed to the Co-doping which altered CMO’s surface electronic structures and properties.Considering the simplicity of synthesis route and the abundance of the pertinent elements,the synthesized CMCO shows a promising prospect as a candidate for the development of earth-abundant,metal-based,and cost-effective electrocatalyst with superior HER activity.Our results also establish a strategy of rational design and construction of novel electrocatalyst toward HER by tailoring band structures of transition metal oxides(TMOs).展开更多
p-n heterostructure(HTS) is a fundamental component for high-performance electronic and optoelectronic device. Vertical stacking through van der Waals(vdW) force is emerging as a feasible technique to construct p-n HT...p-n heterostructure(HTS) is a fundamental component for high-performance electronic and optoelectronic device. Vertical stacking through van der Waals(vdW) force is emerging as a feasible technique to construct p-n HTS. Herein, we designed a novel kind of direct-bandgap C_3N monolayer, via adjusting the arrangement of C and N atoms in C_3N hexagonal cell. On the basis of the density functional theory combined with the non-equilibrium Green's function method, we built two-dimensional vdW-contact phosphorene(BP)/C_3N p-n HTS, and analyzed its electronic and optical properties in comparison with the inplanejointed ones. The strong charge transfer between BP and C_3N segments results in a wide bandgap of 0.48 eV for joint-contact type BP/C_3N HTS, whereas the effective interlayer coupling in vdW-contact type leads to an improved light adsorption as compared to the isolated C_3N monolayer. By fabricating dual-gated BP/C_3N HTS field-effect transistors(FETs), the dynamic transport behaviors demonstrated that the band bending under a lower threshold voltage makes band-to-band tunneling possible for vdW-contact type. Our work suggests that vdW-contact type is superior to joint-contact type in constructing p-n HTS for high-performance electronic and optoelectronic devices.展开更多
The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains unresolved.We address this question using nonperturbat...The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains unresolved.We address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping integral.We simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 meV.Our results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless coupling.We also find that the transition deviates from the weak-coupling Peierls’picture.This work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.展开更多
Organic single crystals(OSCs)offer a unique combination of both individual and collective properties of the employed molecules,but it remains highly challenging to achieve OSCs with both high mobilities and strong flu...Organic single crystals(OSCs)offer a unique combination of both individual and collective properties of the employed molecules,but it remains highly challenging to achieve OSCs with both high mobilities and strong fluorescence emissions for their potential applications in multifunctional optoelectronics.Herein,we demonstrate the design and synthesis of two novel triphenylamine-functionalized thienoacenes-based organic semiconductors,4,8-distriphenylamineethynylbenzo[1,2-b:4,5-b′]dithiophene(4,8-DTEBDT)and 2,6-distriphenylamineethynylbenzo[1,2-b:4,5-b′]dithiophene(2,6-DTEBDT),with high-mobility and strong fluorescence emission.The two compounds show the maximum mobilities up to 0.25 and 0.06 cm^(2) V^(-1) s^(-1),the photoluminescence quantum yields(PLQYs)of 51% and 45%,and the small binding energies down to 55.13 and 58.79 meV.The excellent electrical and optical properties ensured the application of 4,8-DTEBDT and 2,6-DTEBDT single crystals in ultrasensitive UV phototransistors,achieving high photoresponsivity of 9.60×105 and 6.43×10^(4) AW^(-1),and detectivity exceeding 5.68×10^(17) and 2.99×10^(16) Jones.展开更多
Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized mate...Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized materials possessing promising properties.Among them,highly porous conjugated scaffolds with attractive electronic conductivities and high surface areas are one of the representative categories exhibiting diverse taskspecific applications,especially in electrochemical energy storage.In recent years,the mechanochemistry-driven procedures have been deployed to construct conjugated scaffolds with engineered structures and properties leveraging the tunability in chemical structures of building blocks and polymerization capability of diverse catalysts.Therefore,a thorough review of related works is required to gain an in-depth understanding of the mechanochemical synthesis procedure and property-performance relationship of the as-produced conjugated scaffolds.Herein,the mechanochemistry-driven construction of conjugated porous networks(CPNs),the carbon-based materials(e.g.,graphite and graphyne),and carbon supported single atom catalysts(CS-SACs)are discussed and summarized.The electrochemical performance of the afforded conductive scaffolds as electrode materials in supercapacitors and alkali-ion batteries is elucidated.Finally,the challenges and potential opportunities related to the construction of conjugated scaffolds driven by mechanochemistry are also discussed and concluded.展开更多
Engineering polyamide 6(PA6)is preferred for its superior mechanical properties,yet the intrinsic flammability restricts its industrial applications.As one of the biomass phosphorus-containing chemicals,phytic acid(PA...Engineering polyamide 6(PA6)is preferred for its superior mechanical properties,yet the intrinsic flammability restricts its industrial applications.As one of the biomass phosphorus-containing chemicals,phytic acid(PA)is favorable for its high phosphorus content and aggregation ability,making it expected to enhance the fire retardancy of PA6.Herein,a melamine-phytate aggregate(MPA)is prepared by electrostatic interaction in aqueous solution,and applied as a synergist for aluminum diethylphosphinate(ADP)in PA6.The strong synergistic effect exists between ADP and MPA towards PA6,especially when their mass ratio is 3:1 and the total loading is 18 wt%.Compared to the neat PA6,this formula allows for remarkable decreases in peak heat release rate(PHRR),total heat release(THR),and maximum average heat release rate(MARHE)by∼48%,∼27%,and∼30%,respectively,as well as a high synergistic efficiency of∼43%in PHRR.This PA6 composite also presents a V-0 rating in the vertical burning(UL-94)test and a high limiting oxygen index(LOI)of 29.7%.This work offers an eco-friendly strategy for developing bio-based P/N fire-retardant aggregates for fabricating PA6 materials with high fire safety.展开更多
Monolayer borophene, a novel kind of two-dimensional(2D) crystal, has been receiving intensive attention owing to its atomic thickness and metallic characteristics. Rational tuning the anisotropic electronic transport...Monolayer borophene, a novel kind of two-dimensional(2D) crystal, has been receiving intensive attention owing to its atomic thickness and metallic characteristics. Rational tuning the anisotropic electronic transport properties is essential to the application of monolayer borophene in electronic and optoelectronic devices. Herein, we developed an oxidation strategy to tune the anisotropic transport properties of borophene by changing O-defect coverage, using density functional theory combined with the nonequilibrium Green's function formalism. It was found that for monolayer borophene, the preferable current flowing direction between armchair and zigzag could be reversed by modulating the surface O-defect coverage between 0 and 100%. The tunable anisotropic transport properties of oxidized borophene could be attributed to the interplay among several factors, including the surface charge transfer between O-defects and borophene layer, the scattering effects related to the coverage and orientation of O-B-O interfaces, and the additional transport channels through O-defects. Our work unveils the great potential of oxidization strategy in tuning the anisotropic electronic transport properties of monolayer borophene and is of significance to its application in high-performance electronic and optoelectronic nanodevices.展开更多
Dielectric capacitors are receiving increasing attention due to the high-power density and fast charge-discharge speed.However,defects are inevitably induced during the preparation process and then weaken the breakdow...Dielectric capacitors are receiving increasing attention due to the high-power density and fast charge-discharge speed.However,defects are inevitably induced during the preparation process and then weaken the breakdown strength,thereby limiting their energy density.The phenomenon gives rise to self-healing technology.The discovery of sol-gel-derived aluminum oxide with electrolysis and dielectric dual-characteristic provides a novel,simple and cost-effective self-healing method to heal defects and enhance energy density.In this paper,we systematically reviewed the current self-healing technologies and the important progress of electrolysis and dielectric co-existence dielectrics.Finally,we outlook the electrolysis and dielectric co-existence dielectrics and potential challenge.展开更多
Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic...Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic salts generally rely on ionic interaction and hydrogen bonding formation to maintain the porous channels.The synthesis of organic moiety-derived saltswith permanent accessible pores even after removal of the trapped vip molecules,and without the constraint of hydrogen bonding formation still remains a great challenge.Herein,we present an expeditious construction pathway to generate hierarchically nanoporous barium salts without hydrogen bonding formation.The strong ionic interaction of the bariumcation and sulfonate anions led to rapid reaction equilibrium(∼2 min),affording diverse barium-derived ionic polymer(Ba-IP)with permanent porosity and highly polarized channels.The produced Ba-IP materials with abundant cations and anions displayed high CO_(2)/N2 and CO_(2)/CH_(4)separation performance,with the selectivities reaching up to 89.5 and 280,respectively,at 273 K,surpassingmost of the organic polymers functionalized by ionic moieties.展开更多
基金supported by the Natural Science Foundation of China (52277218)the Hubei Provincial Natural Science Foundation of China (2024AFA094)+1 种基金the Excellent Discipline Cultivation Project by JHUN (2023XKZ009)supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,Materials Sciences and Engineering Division under contract number DE-AC05-00OR22725。
文摘Lithium metal(LM)is a promising anode for next-generation batteries due to its high theoretical capacity and low electrode potential.Nonetheless,side reactions,volume change,and unwanted lithium dendrite growth seriously limit the practical application of LM.Herein,with the aid of a hard template approach,a novel lithiophilic CoF_(2)-carbon hollow sphere(CoF_(2)@C-HS)composite material is successfully prepared via a facile in-situ fluorination and etching strategy.The lithiophilic CoF_(2) acts as nucleation sites to reduce nucleation overpotential as well as induces the spatial Li deposition and the formation of LiFrich solid electrolyte interphase(SEI),and the hollow carbon matrix can enhance the electrical conductivity and offer free space for LM deposition.Theoretical simulations reveal that the synergistic effect of lithiophilic CoF_(2) and hollow carbon matrix homogenizes the electric field distribution and Li~+flux.Benefiting from these advantages,the CoF_(2)@C-HS-modified copper substrate electrode delivers an enhanced Coulombic efficiency(CE)of 93.7%for 280 cycles at 1 mA cm^(-2)and 1 mA h cm^(-2).The symmetrical cell using CoF_(2)@C-HS can stably cycle more than 1800 h with a low voltage hysteresis of 11 mV at a current density of 0.5 MA cm^(-2)and an areal capacity of 0.5 mA h cm^(-2).Moreover,the Li@CoF_(2)@C-HS composite anode enables more than 300 stable cycles at 1 C with a capacity retention of 95%in LiFePO_(4)-based full cell and 110 stable cycles at 1 C in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)-based highvoltage full cell.This work might shed a new light on designing lithiophilic hosts to spatially confine LM deposition,realizing dendrite-free LM anodes and the practical applications of LM batteries.
基金supported by the youth project of Guangdong Foshan joint fund of Guangdong Natural Science Foundation(Grant No.2020A1515110601 and Grant No.2019A1515110444)the National Natural Science Foundation of China(No:61804029)the Project of Foshan Science and Technology Innovation Team(No:FS0AA-KJ919-4402-0062).
文摘Ferroelectric ceramics have the potential to be widely applied in the modern industry and military power systems due to their ultrafast charging/discharging speed and high energy density.Considering the structural design and electrical properties of ferroelectric capacitor,it is still a challenge to ffnd out the optimal energy storage of ferroelectric ceramics during the phase-transition process of amorphous/nanocrystalline and polycrystalline.In this work,a ffnite element model suitable for the multiphase ceramic system is constructed based on the phase ffeld breakdown theory.The nonlinear coupling relationship of multiple physical ffelds between multiphase ceramics was taken into account in this model.The basic structures of multiphase ceramics are generated by using the Voronoi diagram construction method.The speciffed structure of multiphase ceramics in the phase-transition process of amorphous/nanocrystalline and polycrystalline was further obtained through the grain boundary diffusion equation.The simulation results show that the multiphase ceramics have an optimal energy storage in the process of amorphous polycrystalline transformation,and the energy storage density reaches the maximum when the crystallinity is 13.96%and the volume fraction of grain is 2.08%.It provides a research plan and idea for revealing the correlation between microstructure and breakdown characteristics of multiphase ceramics.This simulation model realizes the nonlinear coupling of the multiphase ceramic mesoscopic structure and the phase ffeld breakdown.It provides a reference scheme for the structural design and performance optimization of ferroelectric ceramics.
基金funding support of the Key Laboratory of Flame Retardancy Finishing of Textile Materials,CNTAC(Q811580421)Australian Research Council(Nos.DP190102992 and FT190100188)the National Natural Science Foundation of China(Nos.51803200 and 52003104)。
文摘Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene.Herein,phosphorylated MXene/polypropylene(PP)composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine(PEI)and hot-pressing.The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates.Upon hot-pressing,melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases.The composites show significantly improved thermal stability and flame retardancy relative to pure PP,with a low total heat release(THR)of 3.7 kJ/g and a heat release rate(HRR)of 50.0 W/g,which are reduced by 78%and 87%,respectively.In addition,the composites exhibit a high electrical conductivity of~36,700 S/m and an EMI shielding performance of~90 d B over the whole frequency range of 8–12 GHz with a thickness of~400μm.The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments.
基金supported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,as part of the Energy Frontier Research Centers program:CSSAS-The Center for the Science of Synthesis Across Scales-under Award No.DE-SC0019288,located at University of Washington,DCAdditional support for ongoing pyroVED software development came from the Laboratory Directed Research and Development Program at Pacific Northwest National Laboratory(PNNL),a multiprogram national laboratory operated by Battelle for the U.S.Department of Energysupported by the Center for Nanophase Materials Sciences(CNMS),which is aUS Department of Energy,Office of Science User Facility at Oak Ridge National Laboratory(ORNL).
文摘Electron,optical,and scanning probe microscopy methods are generating ever increasing volume of image data containing information on atomic and mesoscale structures and functionalities.This necessitates the development of themachine learning methods for discovery of physical and chemical phenomena from the data,such as manifestations of symmetry breaking phenomena in electron and scanning tunneling microscopy images,or variability of the nanoparticles.Variational autoencoders(VAEs)are emerging as a powerful paradigm for the unsupervised data analysis,allowing to disentangle the factors of variability and discover optimal parsimonious representation.Here,we summarize recent developments in VAEs,covering the basic principles and intuition behind the VAEs.
基金supported by the Center for Nanophase Materials Sciences(CNMS),which is a US Department of Energy,Office of Science User Facility at Oak Ridge National Laboratorysupported by the US Department of Energy,Office of Science,Office of Basic Energy Sciences,MLExchange Project,award number 107514+1 种基金supported by the center for 3D Ferroelectric Microelectronics(3DFeM),an Energy Frontier Research Center funded by the U.S.Department of Energy(DOE),Office of Science,Basic Energy Sciences under Award Number DE-SC0021118the National Science and Technology Council(NSTC),Taiwan,under grant no.NSTC-111-2628-M-006-005.
文摘Optimization of experimental materials synthesis and characterization through active learning methods has been growing over the last decade,with examples ranging from measurements of diffraction on combinatorial alloys at synchrotrons,to searches through chemical space with automated synthesis robots for perovskites.In virtually all cases,the target property of interest for optimization is defined a priori with the ability to shift the trajectory of the optimization based on human-identified findings during the experiment is lacking.Thus,to highlight the best of both human operators and AI-driven experiments,here we present the development of a human–AI collaborated experimental workflow,via a Bayesian optimized active recommender system(BOARS),to shape targets on the fly with human real-time feedback.Here,the human guidance overpowers AI at early iteration when prior knowledge(uncertainty)is minimal(higher),while the AI overpowers the human during later iterations to accelerate the process with the human-assessed goal.We showcase examples of this framework applied to pre-acquired piezoresponse force spectroscopy of a ferroelectric thin film,and in real-time on an atomic force microscope,with human assessment to find symmetric hysteresis loops.It is found that such features appear more affected by subsurface defects than the local domain structure.This work shows the utility of human–AI approaches for curiosity driven exploration of systems across experimental domains.
基金This work was supported by the National Natural Science Foundation of China(Grant No.51902167,51902134)Natural Science Foundation of Ningbo City(Grant No.2021J064)+1 种基金Zhejiang Province Natural Science Foundation of China(Grant No.LY21E020002)Natural Science Foundation of Anhui Province(No.2008085ME133).
文摘Environmentally friendly lead-free ceramics capacitors,with outstanding power density,rapid charging/discharging rate,and superior stability,have been receiving increasing attention of late for their ability to meet the critical requirements of pulsed power devices in low-consumption systems.However,the relatively low energy storage capability must be urgently overcome.Herein,this work reports on leadfree SrTi_(0.875)Nb_(0.1)O_(3)(STN)replacement of(Bi_(0.47)La_(0.03)Na_(0.5))_(0.94)Ba_(0.06)TiO_(3)(BLNBT)ferroelectric ceramics with excellent energy storage performance.Improving relaxor behaviour and breakdown strength(Eb),decreasing grain size,and mitigating large polarization difference are conductive to the enhancement of comprehensive energy storage performances.The phase-field simulation methods are further analysized evolution process of electrical tree in the experimental breakdown.In particular,the 0.70BLNBT-0.30STN ceramic exhibit a large discharged energy density of 4.2 J/cm^(3) with an efficiency of 89.3%at room temperature under electric field of 380 kV/cm.Additionally,for practical applications,the BLNBT-based ceramics achieve a high power density(~62.3 MW/cm^(3))and fast discharged time(~148.8 ns)over broad temperature range(20-200℃).Therefore,this work can provide a simple and effective guideline paradigm for acquiring high-performance dielectric materials in low-consumption systems operating in a wide range of temperatures and long-term operations.
基金financially supported by the National Natural Science Foundation of China (Nos.51922074,22075194,51673138,and 51820105003)the National Key Research and Development Program of China (No.2020YFB1506400)+4 种基金the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (No.20KJA430010)the Tang Scholar,Collaborative Innovation Center of Suzhou Nano Science and Technologythe Fundamental Research Funds for Jiaxing University (Nos.CDN70518005 and CD70519019)Jiaxing Public Welfare Research Program in 2019 (No.2019AY11007)the General Scientific Research Project of Education Department of Zhejiang Province (No.Y201942334)。
文摘As a promising photovoltaic technology, perovskite solar cells(pero-SCs) have developed rapidly over the past few years and the highest power conversion efficiency is beyond 25%. Nowadays, the planar structure is universally popular in pero-SCs due to the simple processing technology and low-temperature preparation.Electron transport layer(ETL) is verified to play a vital role in the device performance of planar pero-SCs. Particularly, the metal oxide(MO) ETL with low-cost, superb versatility, and excellent optoelectronic properties has been widely studied. This review mainly focuses on recent developments in the use of low-temperature-processed MO ETLs for planar pero-SCs. The optical and electronic properties of widely used MO materials of TiO_(2), ZnO, and SnO_(2), as well as the optimizations of these MO ETLs are briefly introduced. The commonly used methods for depositing MO ETLs are also discussed. Then, the applications of different MO ETLs on pero-SCs are reviewed.Finally, the challenge and future research of MO-based ETLs toward practical application of efficient planar peroSCs are proposed.
基金the National Natural Science Foundation of China(No.21801097)the Australian Re-search Council(Nos.DP190102992 and FT190100188).
文摘Renewable and biodegradable polylactide (PLA) has excellent mechanical strength but is highly flammable which restricts its practical applications. Many phosphorus/nitrogen (P/N)-based flame retardants are ef- fective in PLA, but their high addition loading usually decreases the mechanical strength of the PLA bulk. For polyphosphoramides, despite high fire-retardant efficiency, their chemical synthesis often generates chemical wastes as byproducts. Herein, we report an atom-economic and highly efficient oligomeric P/N fire retardant (APN) prepared using a mild Michael addition polymerization with no byproducts. Using only 3 wt% APN, the resulting PLA exhibits desired fire retardancy including a UL-94 V-0 rating and a limiting oxygen index of 37.6%. Furthermore, the toughness of the fire-retardant PLA increases by 85% compared to pure PLA, with both tensile strength and thermal stability preserved. This work offers an atom-economic strategy for synthesizing highly efficient P/N fire retardants for use in the creation of fire-resistant PLA with robust mechanical properties.
基金This work was financially supported by the National Key Research and Development Program of China(No.2020YFB2008502)the National Natural Science Foundation of China(Nos.51972124,51872101,51902115,and 12172143)the Innovation Fund of Wuhan National Laboratory for Optoelectronics(WNLO)。
文摘The development of earth-abundant-metal-based electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction(HER)is crucial for the clean and renewable energy application.Herein,we report a molten-salt method to synthesize Co-doped CaMn_(3)O_(6)(CMO)nanowires(NWs)as effective electrocatalyst for HER.The as-obtained CaMn_(3-x)Co_(x)O_(6)(CMCO)exhibits a small onset overpotential of 70 mV,a required overpotential of 140 mV at a current density of 10 mA·cm^(-2),a Tafel slope of 39 mV·dec^(-1)in 0.1 M HClO_(4),and a satisfying long-term stability.Experimental characterizations combined with density functional theory(DFT)calculations demonstrate that the obtained HER performance can be attributed to the Co-doping which altered CMO’s surface electronic structures and properties.Considering the simplicity of synthesis route and the abundance of the pertinent elements,the synthesized CMCO shows a promising prospect as a candidate for the development of earth-abundant,metal-based,and cost-effective electrocatalyst with superior HER activity.Our results also establish a strategy of rational design and construction of novel electrocatalyst toward HER by tailoring band structures of transition metal oxides(TMOs).
基金supported by the National Natural Science Foundation of China(Grant Nos.1180424251802121 and 51861145202)+3 种基金the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ18E040001)the Jiangsu Provincial Natural Science Funding Project(Grant No.BK20160308)the Jiaxing Science and Technology Project(Grant No.2017AY13009)the 111 Program
文摘p-n heterostructure(HTS) is a fundamental component for high-performance electronic and optoelectronic device. Vertical stacking through van der Waals(vdW) force is emerging as a feasible technique to construct p-n HTS. Herein, we designed a novel kind of direct-bandgap C_3N monolayer, via adjusting the arrangement of C and N atoms in C_3N hexagonal cell. On the basis of the density functional theory combined with the non-equilibrium Green's function method, we built two-dimensional vdW-contact phosphorene(BP)/C_3N p-n HTS, and analyzed its electronic and optical properties in comparison with the inplanejointed ones. The strong charge transfer between BP and C_3N segments results in a wide bandgap of 0.48 eV for joint-contact type BP/C_3N HTS, whereas the effective interlayer coupling in vdW-contact type leads to an improved light adsorption as compared to the isolated C_3N monolayer. By fabricating dual-gated BP/C_3N HTS field-effect transistors(FETs), the dynamic transport behaviors demonstrated that the band bending under a lower threshold voltage makes band-to-band tunneling possible for vdW-contact type. Our work suggests that vdW-contact type is superior to joint-contact type in constructing p-n HTS for high-performance electronic and optoelectronic devices.
基金This work was supported by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences,under Award Number DE-SC0022311.
文摘The relationship between electron–phonon(e-ph)interactions and charge-density-wave(CDW)order in the bismuthate family of high-temperature superconductors remains unresolved.We address this question using nonperturbative hybrid Monte Carlo calculations for the parent compound BaBiO_(3).Our model includes the Bi 6s and O 2pσorbitals and coupling to the Bi-O bond-stretching branch of optical phonons via modulations of the Bi-O hopping integral.We simulate three-dimensional clusters of up to 4000 orbitals,with input model parameters taken from ab initio electronic structure calculations and a phonon energyℏΩ0=60 meV.Our results demonstrate that the coupling to the bond-stretching modes is sufficient to reproduce the CDW transition in this system,despite a relatively small dimensionless coupling.We also find that the transition deviates from the weak-coupling Peierls’picture.This work demonstrates that off-diagonal e-ph interactions in orbital space are vital in establishing the bismuthate phase diagram.
文摘Organic single crystals(OSCs)offer a unique combination of both individual and collective properties of the employed molecules,but it remains highly challenging to achieve OSCs with both high mobilities and strong fluorescence emissions for their potential applications in multifunctional optoelectronics.Herein,we demonstrate the design and synthesis of two novel triphenylamine-functionalized thienoacenes-based organic semiconductors,4,8-distriphenylamineethynylbenzo[1,2-b:4,5-b′]dithiophene(4,8-DTEBDT)and 2,6-distriphenylamineethynylbenzo[1,2-b:4,5-b′]dithiophene(2,6-DTEBDT),with high-mobility and strong fluorescence emission.The two compounds show the maximum mobilities up to 0.25 and 0.06 cm^(2) V^(-1) s^(-1),the photoluminescence quantum yields(PLQYs)of 51% and 45%,and the small binding energies down to 55.13 and 58.79 meV.The excellent electrical and optical properties ensured the application of 4,8-DTEBDT and 2,6-DTEBDT single crystals in ultrasensitive UV phototransistors,achieving high photoresponsivity of 9.60×105 and 6.43×10^(4) AW^(-1),and detectivity exceeding 5.68×10^(17) and 2.99×10^(16) Jones.
基金supported by the U.S.Department of Energy,Office of Science,Basic Energy Sciences,Materials Sciences,and Engineering Division
文摘Mechanochemistry has been recognized as an efficient and sustainable methodology to provide a unique driven force and reaction environments under ambient and neat conditions for the construction of functionalized materials possessing promising properties.Among them,highly porous conjugated scaffolds with attractive electronic conductivities and high surface areas are one of the representative categories exhibiting diverse taskspecific applications,especially in electrochemical energy storage.In recent years,the mechanochemistry-driven procedures have been deployed to construct conjugated scaffolds with engineered structures and properties leveraging the tunability in chemical structures of building blocks and polymerization capability of diverse catalysts.Therefore,a thorough review of related works is required to gain an in-depth understanding of the mechanochemical synthesis procedure and property-performance relationship of the as-produced conjugated scaffolds.Herein,the mechanochemistry-driven construction of conjugated porous networks(CPNs),the carbon-based materials(e.g.,graphite and graphyne),and carbon supported single atom catalysts(CS-SACs)are discussed and summarized.The electrochemical performance of the afforded conductive scaffolds as electrode materials in supercapacitors and alkali-ion batteries is elucidated.Finally,the challenges and potential opportunities related to the construction of conjugated scaffolds driven by mechanochemistry are also discussed and concluded.
基金supported by the Australian Research Council(Grant Nos.FT190100188,LP220100278,DP240102628,DP240102728).
文摘Engineering polyamide 6(PA6)is preferred for its superior mechanical properties,yet the intrinsic flammability restricts its industrial applications.As one of the biomass phosphorus-containing chemicals,phytic acid(PA)is favorable for its high phosphorus content and aggregation ability,making it expected to enhance the fire retardancy of PA6.Herein,a melamine-phytate aggregate(MPA)is prepared by electrostatic interaction in aqueous solution,and applied as a synergist for aluminum diethylphosphinate(ADP)in PA6.The strong synergistic effect exists between ADP and MPA towards PA6,especially when their mass ratio is 3:1 and the total loading is 18 wt%.Compared to the neat PA6,this formula allows for remarkable decreases in peak heat release rate(PHRR),total heat release(THR),and maximum average heat release rate(MARHE)by∼48%,∼27%,and∼30%,respectively,as well as a high synergistic efficiency of∼43%in PHRR.This PA6 composite also presents a V-0 rating in the vertical burning(UL-94)test and a high limiting oxygen index(LOI)of 29.7%.This work offers an eco-friendly strategy for developing bio-based P/N fire-retardant aggregates for fabricating PA6 materials with high fire safety.
基金supported by the National Natural Science Foundation of China(Grant Nos.11804242,51802121,51861145202)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LQ18E040001)+2 种基金the Jiangsu Provincial Natural Science Funding Project(Grant No.BK20160308)the Jiaxing Science and Technology Project(Grant No.2017AY13009)the 111 Program
文摘Monolayer borophene, a novel kind of two-dimensional(2D) crystal, has been receiving intensive attention owing to its atomic thickness and metallic characteristics. Rational tuning the anisotropic electronic transport properties is essential to the application of monolayer borophene in electronic and optoelectronic devices. Herein, we developed an oxidation strategy to tune the anisotropic transport properties of borophene by changing O-defect coverage, using density functional theory combined with the nonequilibrium Green's function formalism. It was found that for monolayer borophene, the preferable current flowing direction between armchair and zigzag could be reversed by modulating the surface O-defect coverage between 0 and 100%. The tunable anisotropic transport properties of oxidized borophene could be attributed to the interplay among several factors, including the surface charge transfer between O-defects and borophene layer, the scattering effects related to the coverage and orientation of O-B-O interfaces, and the additional transport channels through O-defects. Our work unveils the great potential of oxidization strategy in tuning the anisotropic electronic transport properties of monolayer borophene and is of significance to its application in high-performance electronic and optoelectronic nanodevices.
基金supported by the National Natural Science Foundation of China(Youth Program,Grant No.51902134)Zhejiang Public Welfare Technology Application Research Program(GJ22B043506)+2 种基金Jiaxing Public Welfare Research Program(2019 AY11007)Fundamental Research Funds of Jiaxing University(No.CDN70518005)the Innovation Jiaxing·Elite leading plan 2020,International scientific and technological cooperation base of Yangtze River Delta photovoltaic and new energy technology,and Jiaxing University Natural Science Iconic Achievement Cultivation Project 2021。
文摘Dielectric capacitors are receiving increasing attention due to the high-power density and fast charge-discharge speed.However,defects are inevitably induced during the preparation process and then weaken the breakdown strength,thereby limiting their energy density.The phenomenon gives rise to self-healing technology.The discovery of sol-gel-derived aluminum oxide with electrolysis and dielectric dual-characteristic provides a novel,simple and cost-effective self-healing method to heal defects and enhance energy density.In this paper,we systematically reviewed the current self-healing technologies and the important progress of electrolysis and dielectric co-existence dielectrics.Finally,we outlook the electrolysis and dielectric co-existence dielectrics and potential challenge.
基金The research was supported financially by the Division of Chemical Sciences,Geosciences,and Biosciences,Office of Basic Energy Sciences,US Department of Energy.
文摘Organic moieties-derived salts with permanent porosity and polarized channels have shown unique features and attractive performance in the field of adsorption,separation,and conduction.However,state-of-the-art organic salts generally rely on ionic interaction and hydrogen bonding formation to maintain the porous channels.The synthesis of organic moiety-derived saltswith permanent accessible pores even after removal of the trapped vip molecules,and without the constraint of hydrogen bonding formation still remains a great challenge.Herein,we present an expeditious construction pathway to generate hierarchically nanoporous barium salts without hydrogen bonding formation.The strong ionic interaction of the bariumcation and sulfonate anions led to rapid reaction equilibrium(∼2 min),affording diverse barium-derived ionic polymer(Ba-IP)with permanent porosity and highly polarized channels.The produced Ba-IP materials with abundant cations and anions displayed high CO_(2)/N2 and CO_(2)/CH_(4)separation performance,with the selectivities reaching up to 89.5 and 280,respectively,at 273 K,surpassingmost of the organic polymers functionalized by ionic moieties.
