The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is...The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is a lack of information on the best method to coprecipitation NPs.Then,the present study has the objective to measure the effects of the impregnation process of wood veneers through two in situ processes(immersion and vacuum-pressure)using a solution of FeCl_(3)·6H_(2)O,FeCl_(2)·4H_(2)O and ammonia in three tropical species(Pinus oocarpa,Vochysia ferruginea and Vochysia guatemalensis).It was measured the degree of synthesis of iron NPs using weight and density gains,Fe^(3+) absorption,emission scanning electron microscope(SEM),Fournier transform infrared spectroscopy(FT-IR)and for magnetic properties were measured using vibrating sample magnetometry(VSM).After 5-layer veneer panels were fabricated,we evaluated their physical and mechanical properties.Wood samples impregnated by vacuum-pressure methods showed the higher amount of Fe_(3)O_(4)NPs formation,which was observed in the SEM,X-ray diffraction(XDR),FT-IR and VSM.Vacuum-pressure on treatment presented higher ferrite signals and better magnetic properties.Vochysia ferruginea presented the greatest magnetization properties.The magnetization treated causes probably a degradation of the cell wall,which weakens its mechanical properties,especially internal bonding.展开更多
Iron-rich compounds with the tetragonal ThMn12-type structure have the potential to meet current demands for rare-earth-lean permanent magnets with high energy density and operating temperatures of 150-200℃.However,w...Iron-rich compounds with the tetragonal ThMn12-type structure have the potential to meet current demands for rare-earth-lean permanent magnets with high energy density and operating temperatures of 150-200℃.However,while it is normal for magnet technology to lag behind the development of underlying magnetic material,this gap has always been unusually large for ThMn12-type magnets.The gap has widened further in recent years,as excellent combinations of intrinsic magnetic properties have been obtained in compounds synthesized with a smaller amount of structure-stabilizing elements(e.g.,SmFe11V or Sm0.8Zr0.2Fe9.2Co2.3Ti0.5)or with no such elements(i.e.,SmFe9.6Co2.4 thin films).The search for promising compounds continues-with increasing help coming from theoretical calculations.Unfortunately,progress in the development of magnets beyond polymer-bonded interstitially modified powders remains marginal.The introduction of lanthanum(La)was found to stabilize low-meltingtemperature minority phases in Sm(Fe,Ti)12 alloys,thus allowing for liquid-phase sintering for the first time.The high reactivity of La,however,has apparently undermined the development of coercivity(Hc).A controlled crystallization of the initially suppressed ThMn12-type phase makes"bulk"magnetic hardening possible,not only in Sm-Fe-V alloys(in which it has been known since the 1990s),but also is in La-added(Ce,Sm)(Fe,Ti)12 alloys.The properties of the bulk-hardened alloys,however,remain unsatisfactory.Mechanochemically synthesized(Sm,Zr)(Fe,Si)12 and(Sm,Zr)(Fe,Co,Ti)12 powders may become suitable for sintering into powerful fully dense magnets,although not before a higher degree of anisotropy in both alloys and a higher Hc in the latter alloy have been developed.展开更多
The demand for building-integrated photovoltaics and portable energy systems based on flexible photovoltaic technology such as perovskite embedded with exceptional flexibility and a superior power-to-mass ratio is eno...The demand for building-integrated photovoltaics and portable energy systems based on flexible photovoltaic technology such as perovskite embedded with exceptional flexibility and a superior power-to-mass ratio is enormous.The photoactive layer,i.e.,the perovskite thin film,as a critical component of flexible perovskite solar cells(F-PSCs),still faces long-term stability issues when deformation occurs due to encountering temperature changes that also affect intrinsic rigidity.This literature investigation summarizes the main factors responsible for the rapid destruction of F-PSCs.We focus on long-term mechanical stability of F-PSCs together with the recent research protocols for improving this performance.Furthermore,we specify the progress in F-PSCs concerning precise design strategies of the functional layer to enhance the flexural endurance of perovskite films,such as internal stress engineering,grain boundary modification,self-healing strategy,and crystallization regulation.The existing challenges of oxygen-moisture stability and advanced encapsulation technologies of F-PSCs are also discussed.As concluding remarks,we propose our viewpoints on the large-scale commercial application of F-PSCs.展开更多
Mixed cation and anion based perovskites solar cells exhibited enhanced stability under outdoor conditions,however,it yielded limited power conversion efficiency when TiO_(2) and Spiro-OMeTAD were employed as electron...Mixed cation and anion based perovskites solar cells exhibited enhanced stability under outdoor conditions,however,it yielded limited power conversion efficiency when TiO_(2) and Spiro-OMeTAD were employed as electron and hole transport layer(ETL/HTL)respectively.The inevitable interfacial recombination of charge carriers at ETL/perovskite and perovskite/HTL interface diminished the efficiency in planar(n-i-p)perovskite solar cells.By employing computational approach for uni-dimensional device simulator,the effect of band offset on charge recombination at both interfaces was investigated.We noted that it acquired cliff structure when the conduction band minimum of the ETL was lower than that of the perovskite,and thus maximized interfacial recombination.However,if the conduction band minimum of ETL is higher than perovskite,a spike structure is formed,which improve the performance of solar cell.An optimum value of conduction band offset allows to reach performance of 25.21%,with an open circuit voltage(VOC)of 1231 mV,a current density JSC of 24.57 mA/cm^(2) and a fill factor of 83.28%.Additionally,we found that beyond the optimum offset value,large spike structure could decrease the performance.With an optimized energy level of Spiro-OMeTAD and the thickness of mixed-perovskite layer performance of 26.56% can be attained.Our results demonstrate a detailed understanding about the energy level tuning between the charge selective layers and perovskite and how the improvement in PV performance can be achieved by adjusting the energy level offset.展开更多
The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to th...The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to their high performance. Among the different battery components, the separator allows the control of lithium ion diffusion between the electrodes. To overcome some drawbacks of liquid electrolytes, including safety and environmental issues, solid polymer electrolytes (SPEs) are being developed. In this work, a UV photocurable polyurethane acrylate (PUA) resin has been blended with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) up to 30 wt% LiTFSI content to reach a maximum ionic conductivity of 0.0032 mS/cm at room temperature and 0.09 mS/cm at 100 ℃. Those values allowed applying the developed materials as photocurable SPE in Swagelok type Li/C-LiFePO_(4) half-cells, reaching a battery discharge capacity value of 139 mAh.g^(−1) at C/30 rate. Those results, together with the theoretical studies of the discharge capacity at different C-rates and temperatures for batteries with LiTFSI/PUA SPE demonstrate the suitability of the developed photocurable SPE for LIB applications.展开更多
The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,t...The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,transverse and longitudinal velocity distribution of the glasses with different compositions were studied.Furthermore,the influence of these factors on the width and thickness of the flexible glass plate was investigated.It is found that the internal and external heat exchange of glass has a dominant influence on the viscosity variation during the UTG forming process,which is inconsistent with the general viscosity-temperature dependence.The glass that first reaches the lower limit of forming viscosity can significantly resist the shrinking effect caused by surface tension,making the glass wider during the forming.If the original glass width remains unchanged,the glass thickness or feeding speed is reduced,wider and thinner flexible glasses can be produced.展开更多
Perovskite solar cells(PSCs)hold promise for the next generation of photovoltaic technology because of their high power conversion efficiency(PCE)and low manufacturing cost.Methylammonium(MA)-based perovskites are the...Perovskite solar cells(PSCs)hold promise for the next generation of photovoltaic technology because of their high power conversion efficiency(PCE)and low manufacturing cost.Methylammonium(MA)-based perovskites are the most studied compositions as single cation or mixed cation for PSCs because of their high PCE.展开更多
As metal−organic framework(MOF)production scales up to meet industrial needs,the MOF field finds itself looking for less hazardous and more energy efficient synthetic protocols.Effective methods that operate under amb...As metal−organic framework(MOF)production scales up to meet industrial needs,the MOF field finds itself looking for less hazardous and more energy efficient synthetic protocols.Effective methods that operate under ambient conditions will be a huge production advantage that can promote MOF industrialization.To deepen our understanding of room temperature(RT)MOF synthesis,we investigate RT formation of Hf and Ce UiO-66 derivatives.We report the first successful RT synthesis of Hf UiO-66-X(X=–COOH,–NO_(2),–NH_(2),–Br and–(OH)2)by first forming a hafnium oxocluster at 80℃ in water or 120℃ in DMF and subsequently adding the linker at RT.Further,we present a green,one-step synthesis protocol for Ce UiO-66 derivatives in aqueous media either with or without a modulator.We compare the crystallinity,morphology,and yield of these one-step and two-step RT methods.This study advances current chemical understanding of RT synthesis of Hf and Ce UiO-66 structures and could help material chemists develop green RT synthesis protocols for other MOF structures.展开更多
The combination of a zirconium metal-organic cluster and a Keggin type polyoxotungstate into a compound of the formula[Zr_(6)(μ_(3)-O)_(4)(μ_(3)-OH)_(4)(μ-OOCC_(6)H_(5))_(8)(H_(2)O)_(8)][SiW_(12)O_(4)0]led to a che...The combination of a zirconium metal-organic cluster and a Keggin type polyoxotungstate into a compound of the formula[Zr_(6)(μ_(3)-O)_(4)(μ_(3)-OH)_(4)(μ-OOCC_(6)H_(5))_(8)(H_(2)O)_(8)][SiW_(12)O_(4)0]led to a chemically and photochemically stable material in which a synergistic effect between the metal-organic cluster and the polyoxometalate allows marked enhancement of the photochemical activity of the single ionic components toward the photooxidation of dyes.展开更多
A series of p-alkylthio-substituted phenyl-1,2,3,5-dithiadiazolyl radicals,p-R-PhDTDA(R=SMe(2),SEt(3),S^(n)Pr(4),S^(i)Pr(5),S^(t)Bu(6)),and the prototypical(R=H(1))phenyl derivative exhibit a thermally driven solid-li...A series of p-alkylthio-substituted phenyl-1,2,3,5-dithiadiazolyl radicals,p-R-PhDTDA(R=SMe(2),SEt(3),S^(n)Pr(4),S^(i)Pr(5),S^(t)Bu(6)),and the prototypical(R=H(1))phenyl derivative exhibit a thermally driven solid-liquid transition accompanied by a spin-state change from diamagnetic(S=0)π-dimers to a pair of paramagnetic(S=1/2)radicals.X-ray crystallography reveals that most derivatives form phase-pure ciscofacial dimers,except 3 which crystallizes as three distinct polymorphs:3αdisplays a sandwich-type herringbone structure stabilized by intermolecular S…S chalcogen bonding(isostructural with 2)while 3βand 3γfeature slippedπ-stacked herringbone arrangements(ABAB and AA’BB’,respectively).In these latter forms,the alkyl groups act as steric buffers between adjacent stacks,a structural motif retained in derivatives 4-6.Differential scanning calorimetry(DSC),hot-stage microscopy,and vibrating sample magnetometry(VSM)collectively demonstrate a hysteretic phase transition in 1-6 with magnetic bistability arising from supercooling of the paramagnetic liquid phase.These results establish a new design paradigm for stimuli-responsive materials in which molecular packing,thermal behavior,and spin states are intrinsically linked through phase transitions.展开更多
Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and ...Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and e-PTFE significantly decreases the proton conduction efficiency and durability of the PEM.In this study,the polyphenolamine treatment method(TA)is employed to effectively enhance the hydrophilicity and interfacial compatibility of e-PTFE,as well as to functionalize the surface of the free radical scavenger ZrO_(2) filler.The surface of the modified e-PTFE and ZrO_(2) is rich in polar phenolic hydroxyl groups and amino groups,which effectively enhance the three-dimensional interface compatibility of the e-PTFE/PFSA reinforced composite membrane(RCM),and improve the proton conductivity by establishing a three-dimensionally-reinforced hydrogen bonding network.The proton conductivity of the RCM is 0.203 S cm^(-1) at 80℃,and the tensile strength is 50.7 MPa.The peak power density of the hydrogen fuel cell based on the composite membrane is 1.46 W cm^(-2) at 80℃ and 50%RH.Moreover,the durability of the composite membrane is considerably improved by the redox properties of the surface functional groups of e-PTFE and the valence-changing properties of ZrO_(2).Following a 72-hour Fenton reaction,the mass loss of the TA@ZrO_(2)/e-PTFE RCM was found to be only 13.5%.The accelerated durability test indicates that the TA@ZrO_(2)/e-PTFE RCM can still provide a current density of 1.3 A cm^(-2) after 5500 dry/wet cycles at 0.55 V.展开更多
Herein we explore the opportunities arising from combining magnetic properties and porosity in metal-organic materials.In this sense,we have prepared an adenine based homometallic wheel-shaped heptameric[Cu_(7)(μ-ade...Herein we explore the opportunities arising from combining magnetic properties and porosity in metal-organic materials.In this sense,we have prepared an adenine based homometallic wheel-shaped heptameric[Cu_(7)(μ-adeninato)_(6)(μ_(3)-OH)_(6)(μ-OH_(2))_(4)]^(2+)entity containing two metal coordination environments:CuO_(6)at the core of the wheel with an unusually modest Jahn-Teller distortion and six peripheral CuN_(2)O_(4)with a more pronounced elongation.展开更多
Correction for‘An in solution adsorption characterization technique based on the response to an external magnetic field of porous paramagnetic materials:application on supramolecular metal-adenine frameworks containi...Correction for‘An in solution adsorption characterization technique based on the response to an external magnetic field of porous paramagnetic materials:application on supramolecular metal-adenine frameworks containing heterometallic heptameric clusters’by Jon Pascual-Colino et al.,Inorg.Chem.Front.,2023,https://doi.org/10.1039/d2qi01994a.展开更多
UiO-66,reported in 2008,inspired the ongoing chemistry of group 4 metal–organic frameworks and it is still one of the most studied MOFs due to its exceptional stability.The tightness of their building blocks and bond...UiO-66,reported in 2008,inspired the ongoing chemistry of group 4 metal–organic frameworks and it is still one of the most studied MOFs due to its exceptional stability.The tightness of their building blocks and bond strength make it tough to access new topologies,unless the building blocks are changed or defect engineering is employed,which in turn lead to different nominal stoichiometries.However,well selected structure directing agents and harsh synthesis conditions allowed the isolation of the first polymorph of UiO-66,named EHU-30.Herein,we provide evidence for the generalization of the synthetic approach with four new EHU-30 isoreticular compounds,based on amino-functionalized linkers and zirconium and hafnium as metal centres:EHU-30-NH_(2)(M)and EHU-30-NHR(M)(M:Zr,Hf;R:2-carboxypropyl).The crystal structure analysis reveals that their framework is more porous than that of their polymorphic counterpart.Furthermore,due to the current relevance of MOFs in greenhouse gas capture and in water harvesting methodologies,we have explored CO_(2)and water vapour adsorption on the new polymorphic phases,by means of experimental and computational resources,and compared to the parent EHU-30.The amino functionalization makes the EHU-30 series more prone to CO_(2)and water vapour adsorption.Besides,the water adsorption isotherms show an interesting crossing sensitive to temperature,sorption cycles and functionalization of the linker,which has been attributed to a localized structural transformation from EHU-30 to UiO-66.Finally,time-of-flight(TOF)powder neutron diffraction experiments were also conducted to locate the preferred adsorption sites for water in functionalized and parent EHU-30 structures.展开更多
Quantitative imaging of luminescent signals,ranging from electrochemiluminescence(ECL)and chemiluminescence to colorimetric assays,is increasingly performed using consumer-grade digital cameras and smartphones.However...Quantitative imaging of luminescent signals,ranging from electrochemiluminescence(ECL)and chemiluminescence to colorimetric assays,is increasingly performed using consumer-grade digital cameras and smartphones.However,device-dependent variability,nonlinear signal encoding,and the absence of standardized workflows hinder reproducibility and quantification accuracy.This work presents a generalized methodology for robust signal quantification in luminescent systems using digital imaging,with ECL as a model case.By combining synchronized electrochemical control,manual optimization of imaging parameters,gamma correction,and color space transformations,accurate device-independent analysis is enabled.Using Ru(bpy)_(3)^(2+)/TPrA as a test system,we evaluate RGB,CIEXYZ,and CIELAB color spaces,identifying optimal channels for sensitivity and dynamic range.Our performance assessment underscores the importance of transfer function selection and supports both linear and nonlinear quantification models.Results show that linearized r and X color channels offer broad dynamic ranges with moderate sensitivity,while encoded R and a*channels provide higher sensitivity at low concentrations,requiring nonlinear modeling to extend their quantification range.This scalable approach enables standardized,high-throughput optical analysis using low-cost camera platforms,with broad applications in diagnostics,biosensing,and analytical chemistry.展开更多
A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors...A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors that can induce a crystal phase transformation(such as humidity,intense light flux,temperature,etc.).In this perspective,it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring.In this paper we propose Raman spectroscopy as the ideal technique to solve this problem.The vibrational analysis of CsPbI3 in the a-phase and 5-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework.Finally,the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.展开更多
Micro(nano)plastics(MNPs)have become a significant environmental concern due to their widespread presence in the biosphere and potential harm to ecosystems and human health.Here,we propose for the first time a MNPs ca...Micro(nano)plastics(MNPs)have become a significant environmental concern due to their widespread presence in the biosphere and potential harm to ecosystems and human health.Here,we propose for the first time a MNPs capture,utilization,and storage(PCUS)concept to achieve MNPs remediation from water while meeting economically productive upcycling and environmentally sustainable plastic waste management.A highly efficient capturing material derived from surface-modified woody biomass waste(M-Basswood)is developed to remove a broad spectrum of multidimensional and compositional MNPs from water.The M-Basswood delivered a high and stable capture efficiency of>99.1%at different pH or salinity levels.This exceptional capture performance is driven by multiscale interactions between M-Basswood and MNPs,involving physical trapping,strong electrostatic attractions,and triggered MNPs cluster-like aggregation sedimentation.Additionally,the in vivo biodistribution of MNPs shows low ingestion and accumulation of MNPs in the mice organs.After MNPs remediation from water,the M-Basswood,together with captured MNPs,is further processed into a high-performance composite board product where MNPs serve as the glue for utilization and storage.Furthermore,the life cycle assessment(LCA)and techno-economic analysis(TEA)results demonstrate the environmental friendliness and economic viability of our proposed full-chain PCUS strategy,promising to drive positive change in plastic pollution and foster a circular economy.展开更多
Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained i...Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained in 0.95Pb_(0.92)La_(0.08)(Zr_(0.70)Ti_(0.30))_(0.98)O_(3)-0.05BiFeO_(3)(BFO-La-codoped PZT)epitaxial thin films deposited on the(100),(110)and(111)oriented SrTiO_(3)(STO)substrates by a sol-gel method.The thin film deposited on the(111)oriented STO substrate exhibited a stronger EC effect(~20.6 K at 1956 kV/cm)near room temperature.However,the thin films deposited on the(100)and(110)oriented STO substrates exhibited a stronger EC effect(~18.8 K at 1852 kV/cm and~20.8 K at 1230 kV/cm,respectively)around the peak of the dielectric permittivity(T_(m),~375 K).Particularly,as the direction of the applied electric field was switched(E<0),the DT of the(100)-oriented thin films around T_(m) was enhanced significantly from 18.8 K to 38.1 K.The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon.It can be concluded that the BFO-La-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.展开更多
Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic dev...Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.展开更多
In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical por...In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical porous carbon foam supported carbon-encapsulated chromium carbide nano-particles(Cr_(3)C_(2)@C/HPCF),in which the well-distributed conductive Cr_(3)C_(2) nano-particles can act as powerful chemical adsorbent and are effective in restraining the shuttle effect of lithium polysulfides(LiPSs).Test results show that the Cr_(3)C_(2)@C/HPCF based sulfur electrodes with 75 wt.%of sulfur exhibit a high initial discharging capacity of 1,321.1 mAh·g^(−1) at 0.1 C(3.5 mg·cm^(−2)),and a reversible capacity can still maintain stability at 1,002.1 mAh·g^(−1) after 150 cycles.Even increasing the areal sulfur loading to 4 mg·cm^(−2),the electrodes can still deliver an initial discharging capacity of 948.0 mAh·g^(−1) at 0.5 C with ultra-slow capacity decay rate of 0.075%per cycle during 500 cycles.Furthermore,the adsorption energy between the Cr_(3)C_(2) surface and LiPSs as well as theoretic analysis based on first-principles is also investigated.展开更多
文摘The impregnation of nanoparticles magnetified into wood had been developed by different methods,like surface chemical coprecipitation and vacuum-pressure coprecipitation of magnetic nanoparticles(NPs).However,there is a lack of information on the best method to coprecipitation NPs.Then,the present study has the objective to measure the effects of the impregnation process of wood veneers through two in situ processes(immersion and vacuum-pressure)using a solution of FeCl_(3)·6H_(2)O,FeCl_(2)·4H_(2)O and ammonia in three tropical species(Pinus oocarpa,Vochysia ferruginea and Vochysia guatemalensis).It was measured the degree of synthesis of iron NPs using weight and density gains,Fe^(3+) absorption,emission scanning electron microscope(SEM),Fournier transform infrared spectroscopy(FT-IR)and for magnetic properties were measured using vibrating sample magnetometry(VSM).After 5-layer veneer panels were fabricated,we evaluated their physical and mechanical properties.Wood samples impregnated by vacuum-pressure methods showed the higher amount of Fe_(3)O_(4)NPs formation,which was observed in the SEM,X-ray diffraction(XDR),FT-IR and VSM.Vacuum-pressure on treatment presented higher ferrite signals and better magnetic properties.Vochysia ferruginea presented the greatest magnetization properties.The magnetization treated causes probably a degradation of the cell wall,which weakens its mechanical properties,especially internal bonding.
基金supported by the US Department of Energy,United States(DE-FG02-90ER45413)EU Horizon 2020 Program(686056–NOVAMAG)Ford Motor Company,United States.
文摘Iron-rich compounds with the tetragonal ThMn12-type structure have the potential to meet current demands for rare-earth-lean permanent magnets with high energy density and operating temperatures of 150-200℃.However,while it is normal for magnet technology to lag behind the development of underlying magnetic material,this gap has always been unusually large for ThMn12-type magnets.The gap has widened further in recent years,as excellent combinations of intrinsic magnetic properties have been obtained in compounds synthesized with a smaller amount of structure-stabilizing elements(e.g.,SmFe11V or Sm0.8Zr0.2Fe9.2Co2.3Ti0.5)or with no such elements(i.e.,SmFe9.6Co2.4 thin films).The search for promising compounds continues-with increasing help coming from theoretical calculations.Unfortunately,progress in the development of magnets beyond polymer-bonded interstitially modified powders remains marginal.The introduction of lanthanum(La)was found to stabilize low-meltingtemperature minority phases in Sm(Fe,Ti)12 alloys,thus allowing for liquid-phase sintering for the first time.The high reactivity of La,however,has apparently undermined the development of coercivity(Hc).A controlled crystallization of the initially suppressed ThMn12-type phase makes"bulk"magnetic hardening possible,not only in Sm-Fe-V alloys(in which it has been known since the 1990s),but also is in La-added(Ce,Sm)(Fe,Ti)12 alloys.The properties of the bulk-hardened alloys,however,remain unsatisfactory.Mechanochemically synthesized(Sm,Zr)(Fe,Si)12 and(Sm,Zr)(Fe,Co,Ti)12 powders may become suitable for sintering into powerful fully dense magnets,although not before a higher degree of anisotropy in both alloys and a higher Hc in the latter alloy have been developed.
基金supported by the National Key Research and Development Program of China(2022YFB4200052)the National Natural Science Foundation of China(No.21975088)+2 种基金the Department of Science and Technology of Hubei Province(2022EHB009)the China Postdoctoral Science Foundation(2022M711236)S.A.thanks European Research Council(MOLEMAT-726360)for support.
文摘The demand for building-integrated photovoltaics and portable energy systems based on flexible photovoltaic technology such as perovskite embedded with exceptional flexibility and a superior power-to-mass ratio is enormous.The photoactive layer,i.e.,the perovskite thin film,as a critical component of flexible perovskite solar cells(F-PSCs),still faces long-term stability issues when deformation occurs due to encountering temperature changes that also affect intrinsic rigidity.This literature investigation summarizes the main factors responsible for the rapid destruction of F-PSCs.We focus on long-term mechanical stability of F-PSCs together with the recent research protocols for improving this performance.Furthermore,we specify the progress in F-PSCs concerning precise design strategies of the functional layer to enhance the flexural endurance of perovskite films,such as internal stress engineering,grain boundary modification,self-healing strategy,and crystallization regulation.The existing challenges of oxygen-moisture stability and advanced encapsulation technologies of F-PSCs are also discussed.As concluding remarks,we propose our viewpoints on the large-scale commercial application of F-PSCs.
基金funding from the European Union H2020 programme under Excellence research,ERC grant MOLEMAT(726360)PARASOL(RTI2018-102292-B-I00)from Spanish ministry of Science and Innovation。
文摘Mixed cation and anion based perovskites solar cells exhibited enhanced stability under outdoor conditions,however,it yielded limited power conversion efficiency when TiO_(2) and Spiro-OMeTAD were employed as electron and hole transport layer(ETL/HTL)respectively.The inevitable interfacial recombination of charge carriers at ETL/perovskite and perovskite/HTL interface diminished the efficiency in planar(n-i-p)perovskite solar cells.By employing computational approach for uni-dimensional device simulator,the effect of band offset on charge recombination at both interfaces was investigated.We noted that it acquired cliff structure when the conduction band minimum of the ETL was lower than that of the perovskite,and thus maximized interfacial recombination.However,if the conduction band minimum of ETL is higher than perovskite,a spike structure is formed,which improve the performance of solar cell.An optimum value of conduction band offset allows to reach performance of 25.21%,with an open circuit voltage(VOC)of 1231 mV,a current density JSC of 24.57 mA/cm^(2) and a fill factor of 83.28%.Additionally,we found that beyond the optimum offset value,large spike structure could decrease the performance.With an optimized energy level of Spiro-OMeTAD and the thickness of mixed-perovskite layer performance of 26.56% can be attained.Our results demonstrate a detailed understanding about the energy level tuning between the charge selective layers and perovskite and how the improvement in PV performance can be achieved by adjusting the energy level offset.
基金Work supported by the Portuguese national funds(PIDDAC),through the Portuguese Foundation for Science and Technology(FCT)and FCT/MCTES:projects UID/FIS/04650/2020.UID/QUI/0686/2020,UID/CTM/50025/2020,UIDB/05549/2020,PTDC/FIS-MAC/28157/2017Grants SFRH/BD/140842/2018(J.C.B.),CEECIND/00833/2017(R.G.)and SFRH/BPD/112547/2015(C.M.C.).Financial support from the Basque Government Industry Departments under the ELKARTEK and HAZITEK programs is also acknowledged.
文摘The increased demand of electronic devices promotes the development of advanced and more efficient energy storage devices, such as batteries. Lithium-ion batteries (LIBs) are the most studied battery systems due to their high performance. Among the different battery components, the separator allows the control of lithium ion diffusion between the electrodes. To overcome some drawbacks of liquid electrolytes, including safety and environmental issues, solid polymer electrolytes (SPEs) are being developed. In this work, a UV photocurable polyurethane acrylate (PUA) resin has been blended with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) up to 30 wt% LiTFSI content to reach a maximum ionic conductivity of 0.0032 mS/cm at room temperature and 0.09 mS/cm at 100 ℃. Those values allowed applying the developed materials as photocurable SPE in Swagelok type Li/C-LiFePO_(4) half-cells, reaching a battery discharge capacity value of 139 mAh.g^(−1) at C/30 rate. Those results, together with the theoretical studies of the discharge capacity at different C-rates and temperatures for batteries with LiTFSI/PUA SPE demonstrate the suitability of the developed photocurable SPE for LIB applications.
基金the National Key Research and Development Program of China(No.2022YFB3603300)。
文摘The forming process of the flexible ultrathin glasses(UTG)prepared by the redrawing method was numerically simulated using ANSYS Polyflow software.In the forming process by the redrawing method,temperature,viscosity,transverse and longitudinal velocity distribution of the glasses with different compositions were studied.Furthermore,the influence of these factors on the width and thickness of the flexible glass plate was investigated.It is found that the internal and external heat exchange of glass has a dominant influence on the viscosity variation during the UTG forming process,which is inconsistent with the general viscosity-temperature dependence.The glass that first reaches the lower limit of forming viscosity can significantly resist the shrinking effect caused by surface tension,making the glass wider during the forming.If the original glass width remains unchanged,the glass thickness or feeding speed is reduced,wider and thinner flexible glasses can be produced.
文摘Perovskite solar cells(PSCs)hold promise for the next generation of photovoltaic technology because of their high power conversion efficiency(PCE)and low manufacturing cost.Methylammonium(MA)-based perovskites are the most studied compositions as single cation or mixed cation for PSCs because of their high PCE.
基金supported by the Spanish State Research Agency(AEI)and the European Regional Development Fund(ERFD)through the project PID2020–15935RB-C42The European Union’s Horizon 2020 Research and Innovation Programmes is also acknowledged for the funding of the LCSC3-RES-25-20204AirCRAFT(Ref.:101022633)project+1 种基金In addition,4AirCRAFT project was also supported by Japan Science and Technology Agency(JST)Mission Innovation Challenge was supported by the Sao Paulo Research Foundation(FAPESP).
文摘As metal−organic framework(MOF)production scales up to meet industrial needs,the MOF field finds itself looking for less hazardous and more energy efficient synthetic protocols.Effective methods that operate under ambient conditions will be a huge production advantage that can promote MOF industrialization.To deepen our understanding of room temperature(RT)MOF synthesis,we investigate RT formation of Hf and Ce UiO-66 derivatives.We report the first successful RT synthesis of Hf UiO-66-X(X=–COOH,–NO_(2),–NH_(2),–Br and–(OH)2)by first forming a hafnium oxocluster at 80℃ in water or 120℃ in DMF and subsequently adding the linker at RT.Further,we present a green,one-step synthesis protocol for Ce UiO-66 derivatives in aqueous media either with or without a modulator.We compare the crystallinity,morphology,and yield of these one-step and two-step RT methods.This study advances current chemical understanding of RT synthesis of Hf and Ce UiO-66 structures and could help material chemists develop green RT synthesis protocols for other MOF structures.
基金financial support from the Basque Government(IT1291-19)from the University of the Basque Country(predoctoral fellowships for J.P.C.and M.P.I.:PIF17/51 and PIF18/175)+1 种基金from the Spanish Ministry of Science and Innovation(PID2019-108028GB-C21)Technical and human support provided by SGIker(UPV/EHU,MICINN,GV/EJ,and ESF)is also acknowledged.
文摘The combination of a zirconium metal-organic cluster and a Keggin type polyoxotungstate into a compound of the formula[Zr_(6)(μ_(3)-O)_(4)(μ_(3)-OH)_(4)(μ-OOCC_(6)H_(5))_(8)(H_(2)O)_(8)][SiW_(12)O_(4)0]led to a chemically and photochemically stable material in which a synergistic effect between the metal-organic cluster and the polyoxometalate allows marked enhancement of the photochemical activity of the single ionic components toward the photooxidation of dyes.
基金supported by the Academy of Finland(projects 358156,336456,333565)the University of Jyväskylä,and the authors are grateful for technical and human support provided by SGIker(UPV/EHU/ERDF,EU),especially the fruitful discussions with Dr I.Orue.
文摘A series of p-alkylthio-substituted phenyl-1,2,3,5-dithiadiazolyl radicals,p-R-PhDTDA(R=SMe(2),SEt(3),S^(n)Pr(4),S^(i)Pr(5),S^(t)Bu(6)),and the prototypical(R=H(1))phenyl derivative exhibit a thermally driven solid-liquid transition accompanied by a spin-state change from diamagnetic(S=0)π-dimers to a pair of paramagnetic(S=1/2)radicals.X-ray crystallography reveals that most derivatives form phase-pure ciscofacial dimers,except 3 which crystallizes as three distinct polymorphs:3αdisplays a sandwich-type herringbone structure stabilized by intermolecular S…S chalcogen bonding(isostructural with 2)while 3βand 3γfeature slippedπ-stacked herringbone arrangements(ABAB and AA’BB’,respectively).In these latter forms,the alkyl groups act as steric buffers between adjacent stacks,a structural motif retained in derivatives 4-6.Differential scanning calorimetry(DSC),hot-stage microscopy,and vibrating sample magnetometry(VSM)collectively demonstrate a hysteretic phase transition in 1-6 with magnetic bistability arising from supercooling of the paramagnetic liquid phase.These results establish a new design paradigm for stimuli-responsive materials in which molecular packing,thermal behavior,and spin states are intrinsically linked through phase transitions.
基金supported by Chongqing Technology Innovation and Application Development Special Key Project,CSTB2023TIAD-KPX0010 and Chongqing Technology Innovation and Application Development Special Major Project,CSTB2023TIAD-STX0033,and the Science Foundation of National Key Laboratory of Science and Technology on Advanced Composites in Special EnvironmentsNatural Science Foundation of Chongqing,China(Nos.CSTC2021jcyj-msxmX1035,CSTB2022NSCQ-MSX0246,CSTB2022NSCQ-MSX0242,CSTB2022NSCQ-MSX1244,CSTB2022NSCQ-MSX0441,CSTB2022NSCQ-MSX1356,CSTB2022NSCQ-MSX1572,CSTB2022NSCQ-MSX1583,CSTB2022NSCQ-MSX0487,CSTB2022TFII-OFX0034)Fundação para a Ciência e Tecnologia(FCT)for financial support under the framework of Strategic Funding UIDB/04650/2020,UID/FIS/04650/2020,UID/EEA/04436/2020,and under project,10.54499/2022.03931.
文摘Expanded polytetrafluoroethylene(e-PTFE)reinforced perfluorosulfonic acid(PFSA)is the predominant proton exchange membrane(PEM)for hydrogen fuel cells.However,the difference in interfacial properties between PFSA and e-PTFE significantly decreases the proton conduction efficiency and durability of the PEM.In this study,the polyphenolamine treatment method(TA)is employed to effectively enhance the hydrophilicity and interfacial compatibility of e-PTFE,as well as to functionalize the surface of the free radical scavenger ZrO_(2) filler.The surface of the modified e-PTFE and ZrO_(2) is rich in polar phenolic hydroxyl groups and amino groups,which effectively enhance the three-dimensional interface compatibility of the e-PTFE/PFSA reinforced composite membrane(RCM),and improve the proton conductivity by establishing a three-dimensionally-reinforced hydrogen bonding network.The proton conductivity of the RCM is 0.203 S cm^(-1) at 80℃,and the tensile strength is 50.7 MPa.The peak power density of the hydrogen fuel cell based on the composite membrane is 1.46 W cm^(-2) at 80℃ and 50%RH.Moreover,the durability of the composite membrane is considerably improved by the redox properties of the surface functional groups of e-PTFE and the valence-changing properties of ZrO_(2).Following a 72-hour Fenton reaction,the mass loss of the TA@ZrO_(2)/e-PTFE RCM was found to be only 13.5%.The accelerated durability test indicates that the TA@ZrO_(2)/e-PTFE RCM can still provide a current density of 1.3 A cm^(-2) after 5500 dry/wet cycles at 0.55 V.
基金funded by Eusko Jaurlaritza/Gobierno Vasco(IT1291-19,IT1722-22,ELKARTEK program KK-2022/00109)Ministerio de Universidades and the European Union-Next Generation EU(marsa21/52,R.P.A.)+1 种基金Ministerio de Ciencia e Innovación(PID2019-108028GB-C21)Technical and human support provided by SGIker(UPV/EHU,MICINN,GV/EJ,ESF)is also acknowledged.
文摘Herein we explore the opportunities arising from combining magnetic properties and porosity in metal-organic materials.In this sense,we have prepared an adenine based homometallic wheel-shaped heptameric[Cu_(7)(μ-adeninato)_(6)(μ_(3)-OH)_(6)(μ-OH_(2))_(4)]^(2+)entity containing two metal coordination environments:CuO_(6)at the core of the wheel with an unusually modest Jahn-Teller distortion and six peripheral CuN_(2)O_(4)with a more pronounced elongation.
文摘Correction for‘An in solution adsorption characterization technique based on the response to an external magnetic field of porous paramagnetic materials:application on supramolecular metal-adenine frameworks containing heterometallic heptameric clusters’by Jon Pascual-Colino et al.,Inorg.Chem.Front.,2023,https://doi.org/10.1039/d2qi01994a.
基金the financial support from the Basque Government(IT1291-19)from the Spanish Ministry of Science and Innovation(PID2019-108028GB-C21,CTQ2017-92173-EXP and IJC2018-038162-I)+2 种基金Technical and human support provided by SGIker(UPV/EHU,MICINN,GV/EJ,and ESF)HPC support from C3UPO are also acknowledgedthe ISIS Neutron and Muon Source for the award of beam time on GEM(experiment RB1920440).
文摘UiO-66,reported in 2008,inspired the ongoing chemistry of group 4 metal–organic frameworks and it is still one of the most studied MOFs due to its exceptional stability.The tightness of their building blocks and bond strength make it tough to access new topologies,unless the building blocks are changed or defect engineering is employed,which in turn lead to different nominal stoichiometries.However,well selected structure directing agents and harsh synthesis conditions allowed the isolation of the first polymorph of UiO-66,named EHU-30.Herein,we provide evidence for the generalization of the synthetic approach with four new EHU-30 isoreticular compounds,based on amino-functionalized linkers and zirconium and hafnium as metal centres:EHU-30-NH_(2)(M)and EHU-30-NHR(M)(M:Zr,Hf;R:2-carboxypropyl).The crystal structure analysis reveals that their framework is more porous than that of their polymorphic counterpart.Furthermore,due to the current relevance of MOFs in greenhouse gas capture and in water harvesting methodologies,we have explored CO_(2)and water vapour adsorption on the new polymorphic phases,by means of experimental and computational resources,and compared to the parent EHU-30.The amino functionalization makes the EHU-30 series more prone to CO_(2)and water vapour adsorption.Besides,the water adsorption isotherms show an interesting crossing sensitive to temperature,sorption cycles and functionalization of the linker,which has been attributed to a localized structural transformation from EHU-30 to UiO-66.Finally,time-of-flight(TOF)powder neutron diffraction experiments were also conducted to locate the preferred adsorption sites for water in functionalized and parent EHU-30 structures.
文摘Quantitative imaging of luminescent signals,ranging from electrochemiluminescence(ECL)and chemiluminescence to colorimetric assays,is increasingly performed using consumer-grade digital cameras and smartphones.However,device-dependent variability,nonlinear signal encoding,and the absence of standardized workflows hinder reproducibility and quantification accuracy.This work presents a generalized methodology for robust signal quantification in luminescent systems using digital imaging,with ECL as a model case.By combining synchronized electrochemical control,manual optimization of imaging parameters,gamma correction,and color space transformations,accurate device-independent analysis is enabled.Using Ru(bpy)_(3)^(2+)/TPrA as a test system,we evaluate RGB,CIEXYZ,and CIELAB color spaces,identifying optimal channels for sensitivity and dynamic range.Our performance assessment underscores the importance of transfer function selection and supports both linear and nonlinear quantification models.Results show that linearized r and X color channels offer broad dynamic ranges with moderate sensitivity,while encoded R and a*channels provide higher sensitivity at low concentrations,requiring nonlinear modeling to extend their quantification range.This scalable approach enables standardized,high-throughput optical analysis using low-cost camera platforms,with broad applications in diagnostics,biosensing,and analytical chemistry.
基金support of the"Fondazione di Sardegna"within the project L.R 7.CUP F74I19000930007"NG-Light:a new generation of phosphors".Technical support provided by A.Larranaga in SGIker(UPV/EHU,GV/EJ,ESF)is gratefully acknowledged.
文摘A major issue in the development of Lead halide perovskites is the assessment of the crystal structure of the samples,due to their typically limited time-stability,and the understanding of the role of external factors that can induce a crystal phase transformation(such as humidity,intense light flux,temperature,etc.).In this perspective,it is of utmost importance to have at disposal a fast and reliable experimental tool able to give an immediate indication of the polymorph of the sample with the possibility to integrate in-situ measurements for constant monitoring.In this paper we propose Raman spectroscopy as the ideal technique to solve this problem.The vibrational analysis of CsPbI3 in the a-phase and 5-phase and of the Cs4PbI6 secondary phase is reported and all the vibrational modes are assigned by comparing experimental spectra of the phases to Raman modes calculated within the DFT framework.Finally,the mechanism of laser induced phase degradation was studied using in-situ Raman measurements providing new insights on the secondary phase generated during the process.
基金the National Natural Science Foundation of China(grant no.52273091)Knowledge Innovation Program of Wuhan-Basi Research(grant no.2023020201010072)+1 种基金the Fundamental Research Funds for the Central Universities(grant no.691000003)for the financial supportE.L.thanks the University of the Basque Country(Convocatoria de ayudas a grupos de investigación,GIU21/010)for the financial support。
文摘Micro(nano)plastics(MNPs)have become a significant environmental concern due to their widespread presence in the biosphere and potential harm to ecosystems and human health.Here,we propose for the first time a MNPs capture,utilization,and storage(PCUS)concept to achieve MNPs remediation from water while meeting economically productive upcycling and environmentally sustainable plastic waste management.A highly efficient capturing material derived from surface-modified woody biomass waste(M-Basswood)is developed to remove a broad spectrum of multidimensional and compositional MNPs from water.The M-Basswood delivered a high and stable capture efficiency of>99.1%at different pH or salinity levels.This exceptional capture performance is driven by multiscale interactions between M-Basswood and MNPs,involving physical trapping,strong electrostatic attractions,and triggered MNPs cluster-like aggregation sedimentation.Additionally,the in vivo biodistribution of MNPs shows low ingestion and accumulation of MNPs in the mice organs.After MNPs remediation from water,the M-Basswood,together with captured MNPs,is further processed into a high-performance composite board product where MNPs serve as the glue for utilization and storage.Furthermore,the life cycle assessment(LCA)and techno-economic analysis(TEA)results demonstrate the environmental friendliness and economic viability of our proposed full-chain PCUS strategy,promising to drive positive change in plastic pollution and foster a circular economy.
基金supported by the National Natural Science Foundation of China(51402196,51973170)the Innovation Project of Guangxi Graduate Education(YCSW2020047)+3 种基金the Guangxi Natural Science Foundation(2017GXNSFFA198015)the open Foundation of Guangxi Key Laboratory of Optical and Electronic Materials and Devices(20KF-6)the Natural Science Foundation of Shaanxi Province(Grant No.2019JCW-17,2020JCW-15)the Development and Planning Guide Foundation of Xidian University(Grant No.21103200005).
文摘Ferroelectric thin/thick films with large electrocaloric(EC)effect are critical for solid state cooling technologies.Here,large positive EC effects with two EC peaks in a broad temperature range(~100 K)were obtained in 0.95Pb_(0.92)La_(0.08)(Zr_(0.70)Ti_(0.30))_(0.98)O_(3)-0.05BiFeO_(3)(BFO-La-codoped PZT)epitaxial thin films deposited on the(100),(110)and(111)oriented SrTiO_(3)(STO)substrates by a sol-gel method.The thin film deposited on the(111)oriented STO substrate exhibited a stronger EC effect(~20.6 K at 1956 kV/cm)near room temperature.However,the thin films deposited on the(100)and(110)oriented STO substrates exhibited a stronger EC effect(~18.8 K at 1852 kV/cm and~20.8 K at 1230 kV/cm,respectively)around the peak of the dielectric permittivity(T_(m),~375 K).Particularly,as the direction of the applied electric field was switched(E<0),the DT of the(100)-oriented thin films around T_(m) was enhanced significantly from 18.8 K to 38.1 K.The self-induced-poling during the preparing process maybe plays a key role on the magic phenomenon.It can be concluded that the BFO-La-codoped PZT epitaxial thin films are promising candidates for application in the next solid-state cooling devices.
文摘Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.
基金The authors appreciate support by the Natural Science Foundation of Anhui Province(No.1908085ME147)Projects of International Cooperation and Exchanges in Anhui Provincial Key Project of Research(No.202004b11020010)+2 种基金Shenzhen Basic Research Program(Nos.JCYJ20190808141611189,JCYJ20170818100134570,and JCYJ20160422091418366)Basic and applied basic research fund of Guangdong Province(No.2020A1515011018)we are grateful to Instrumental Analysis Center of Shenzhen University(Xili Campus)for the help with TEM,and thanks for technical support by Ceshigo Research Service Agency(www.ceshigo.com)for XAS,ACSTEM and DFT/MD.
文摘In this paper,we use microwave reduction strategy to synthesize a new bi-functional sulfur host material at the service of cathode substrate for lithium-sulfur batteries(LSBs),the composite is made of hierarchical porous carbon foam supported carbon-encapsulated chromium carbide nano-particles(Cr_(3)C_(2)@C/HPCF),in which the well-distributed conductive Cr_(3)C_(2) nano-particles can act as powerful chemical adsorbent and are effective in restraining the shuttle effect of lithium polysulfides(LiPSs).Test results show that the Cr_(3)C_(2)@C/HPCF based sulfur electrodes with 75 wt.%of sulfur exhibit a high initial discharging capacity of 1,321.1 mAh·g^(−1) at 0.1 C(3.5 mg·cm^(−2)),and a reversible capacity can still maintain stability at 1,002.1 mAh·g^(−1) after 150 cycles.Even increasing the areal sulfur loading to 4 mg·cm^(−2),the electrodes can still deliver an initial discharging capacity of 948.0 mAh·g^(−1) at 0.5 C with ultra-slow capacity decay rate of 0.075%per cycle during 500 cycles.Furthermore,the adsorption energy between the Cr_(3)C_(2) surface and LiPSs as well as theoretic analysis based on first-principles is also investigated.
