Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique ...Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.展开更多
Lithium metal is considered as the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,undesirable parasitic reactions,p...Lithium metal is considered as the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,undesirable parasitic reactions,poor cycling stability and safety concerns could be caused by uncontrolled dendrite and high reactivity of Li metal,which hinder the practical application of Li-metal anode in high-energy rechargeable Li metal batteries(LMBs).Here,a facile way is reported to stabilize Li metal anode by building high lithiophilic Mg-Li-Cu alloy.Due to the delocalization of electrons on the deposited lithium enhanced by Cu self-diffusion into Mg-Li alloy,the growth of lithium dendrites could be inhibited by Mg-Li-Cu alloy.Moreover,the parasitic reactions with electrolyte could be avoided by the Mg-Li-Cu alloy anode.It is noteworthy that the symmetric battery life of Mg-Li-Cu alloy electrodes exceeds 9000 h at 1 m A cm^(-2)and 1 m Ah cm^(-2).The full cell(LiFePO_(4)|Mg-Li-Cu)exhibits a specific capacity of 148.2 m Ah g^(-1),with a capacity retention of 96.4%,at 1 C after 500 cycles.This work not only pave the way for application of flexible alloy anode in highly stable LMBs,but also provides novel strategies for preparation and optimization of Mg alloy.展开更多
In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more...In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more Li+during charge and discharge processes due to the increased Ni content in their crystal structure,thereby providing higher energy density.However,a significant challenge associated with Ni-rich layered oxide cathodes is the crossover effect,which arises from the dissolution of Ni^(2+)from the cathode,leading to a rapid decline in battery capacity.Through the delocalization-induced effect of solvent molecules,Ni^(2+)is transformed into a fluorinated transition metal inorganic phase layer,thereby forming a corrosion-resistant Li metal interface.This prevents solvent molecules from being reduced and degraded by Li metal anode.The surface of the Li metal anode exhibits a smooth and flat deposition morphology after long-term cycling.Furthermore,the introduction of Ni^(2+)can enhance the concentration gradient of transition metal ions near the cathode,thereby suppressing the dissolution process of transition metal ions.Even the NCM955 cathode with a mass load of 22 mg cm^(−2)also has great capacity retention after cycling.The Ni^(2+)induced by high electronegative functional groups of solvent under the electron delocalization effect,preventing the Ni ions dissolution of cathode and constructing a corrosion-resistant Li metal interface layer.This work provides new insights into suppressing crossover effects in Li metal batteries with high nickel cathodes.展开更多
Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of e...Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of exact solutions to the equations of motion of atoms in a body-centered cubic(bcc)lattice is analyzed.These solutions take the form of delocalized nonlinear vibrational modes(DNVMs)and can serve as an excellent test of the accuracy of the interatomic potentials used in MD modeling for bcc crystals.The accuracy of the potentials can be checked by comparing the frequency response of DNVMs calculated using this or that interatomic potential with that calculated using the more accurate ab initio approach.DNVMs can also be used to train new,more accurate machine learning potentials for bcc metals.To address the above issues,it is important to analyze the properties of DNVMs,which is the main goal of this work.Considering only the point symmetry groups of the bcc lattice,34 DNVMs are found.Since interatomic potentials are not used in finding DNVMs,they are exact solutions for any type of potential.Here,the simplest interatomic potentials with cubic anharmonicity are used to simplify the analysis and to obtain some analytical results.For example,the dispersion relations for small-amplitude phonon modes are derived,taking into account interactions between up to the fourth nearest neighbor.The frequency response of the DNVMs is calculated numerically,and for some DNVMs examples of analytical analysis are given.The energy stored by the interatomic bonds of different lengths is calculated,which is important for testing interatomic potentials.The pros and cons of using DNVMs to test and improve interatomic potentials for metals are discussed.Since DNVMs are the natural vibrational modes of bcc crystals,any reliable interatomic potential must reproduce their properties with reasonable accuracy.展开更多
The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,thes...The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,these organic molecules often exhibit sluggish reaction kinetics and unsatisfactory utilization of active sites,presenting significant challenges for their practical deployment as electrode materials in aqueous batteries.In this study,we have synthesized a novel organic compound(PTPZ),comprised of a centrally symmetric and fully ladder-type structure,tailored for aqueous proton storage.This unique configuration imparts the PTPZ molecule with high electron delocalization and enhanced structural stability.As an electrode material,PTPZ demonstrates a substantial proton-storage capacity of 311.9mAh g^(-1),with an active group utilization efficiency of up to 89% facilitated by an 8-electron transfer process,while maintaining a capacity retention of 92.89% after 8000 chargingdischarging cycles.Furthermore,in-situ monitoring technologies and various theoretical analyses have pinpointed the associated electrochemical processes of the PTPZ electrode,revealing exceptional redox activity,rapid proton diffusion,and efficient charge transfer.These attributes confer a significant competitive advantage to PTPZ as an anode material for high-performance proton storage devices.Consequently,this work contributes to the rational design of organic electrode materials for the advancement of rechargeable aqueous batteries.展开更多
A pair of asymmetric rigid carbazole-benzonitrile-based emitters were synthesized by strategically alternating donor and acceptor groups along the molecular edges.The spin-flip process is accelerated by both the forma...A pair of asymmetric rigid carbazole-benzonitrile-based emitters were synthesized by strategically alternating donor and acceptor groups along the molecular edges.The spin-flip process is accelerated by both the formation of localized and delocalized charge transfer states due to linearly positioned donors and strong spin-orbital coupling between different excitation feature of the lowest singlet and triplet excited states.This molecular architecture results in a remarkable short delayed lifespan of around 100 ns.The application of the two emitters in organic light-emitting diodes(OLEDs)achieves the highest external quantum efficiencies of 13.0%for the green emitter and 9.1%for the sky-blue emitter.Impressively,these devices maintain their high efficiency even at high luminance levels.The sustained efficiency is ascribed to the effective suppression of exciton quenching by substantially shortening delayed lifespan.These findings underscore the practical utility of the molecular design strategy that incorporates alternate donor and acceptor groups at the molecular periphery for shortening delayed fluorescence lifetime,and hold great promise for the development of high-performance OLEDs.展开更多
The idea of genetic engineering is introduced into the area of product design to improve the design efficiency. A method towards design process optimization based on the design process gene is proposed through analyzi...The idea of genetic engineering is introduced into the area of product design to improve the design efficiency. A method towards design process optimization based on the design process gene is proposed through analyzing the correlation between the design process gene and characteristics of the design process. The concept of the design process gene is analyzed and categorized into five categories that are the task specification gene, the concept design gene, the overall design gene, the detailed design gene and the processing design gene in the light of five design phases. The elements and their interactions involved in each kind of design process gene signprocess gene mapping is drawn with its structure disclosed based on its function that process gene.展开更多
Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for hi...Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for high-temperature application of such material involving high-temperature fatigue properties remains unknown.Here,the high-temperature high-cycle fatigue performance of PST TiAl single crystal has been studied.The result shows that PST TiAl single crystal can withstand more than 107 cyclic loadings at 975℃ under a stress amplitude of 270 MPa,which is significantly higher than traditional TiAl alloys.Experimental observations and atomistic simulations indicate that the improvement of fatigue resistance is attributed to the plastic strain delocalization in uniform lamellar structure,and the plastic deformation is well-distributed and sufficient in each lamella.Even in theα2 lamella with difficult slippage,a large number of stacking fault structures can be observed.The{c+a}dislocations inα2 tend to dissociate into a Frank partial with b=1/6<2^(-)20^(-)3>,forming a ribbon of I1 fault which ensures the continuity of deformation.展开更多
Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to des...Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content,surface area,and electronic conductivity,their performance is still far from satisfactory.Hitherto,there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance.Here,we introduce Ti_(3)C_(2) MXene with sulfur terminals to regulate the electronic configuration of FeN_(4) species and dramatically enhance catalytic activity toward ORR.The MXene with sulfur terminals induce the spin-state transition of FeN_(4) species and Fe 3d electron delocalization with d band center upshift,enabling the Fe(II)ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN_(4) species and ORR kinetics.The resulting FeN_(4)-Ti_(3)C_(2)Sx exhibits comparable catalytic performance to those of commercial Pt-C.The developed wearable ZABs using FeN_(4)-Ti_(3)C_(2)Sx also exhibit fast kinetics and excellent stability.This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.展开更多
With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emittin...With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emitting diodes(OLEDs)owing to their thermally activated delayed fluorescence(TADF)nature.However,the highly rigid molecular skeleton with the oppositely positioned bo ron and nitrogen in generating MR effects results in the intrinsic difficulties in the solution-processing of MR-OLEDs.Here,we demonstrate a facile strategy to increase the solubility,enhance the efficiencies and modulate emission color of MR-TADF molecules by extending aromatic rings and introducing tert-butyls into the MR backbone.Two MR-TADF emitters with smaller singlet-triplet splitting energies(ΔE~(ST))and larger oscillator strengths were prepared conveniently,and the solution-processed MR-OLEDs were fabricated for the first time,exhibiting efficient bluish-green electroluminescence with narrow FWHM of 32 nm and external quantum efficiency of 16.3%,which are even comparable to the state-of-the-art performances of the vacuum-evaporated devices.These results prove the feasibility of designing efficient solutionprocessible MR molecules,offering important clues in developing high-performance solution-processed MR-OLEDs with high efficiency and color purity.展开更多
The quark-antiquark （q^-q） spectrum is studied by solving the Schrōdinger equation in the framework of nonrelativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The...The quark-antiquark （q^-q） spectrum is studied by solving the Schrōdinger equation in the framework of nonrelativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The interactions between quark and antiquark consist of quadratic colour confinement-exchange, one-gluon-exchange, and Goldstone-boson-exchange potentials.展开更多
Electrocatalysis provides an optimal approach for the conversion of carbon dioxide(CO_(2))into high-value chemicals,thereby presenting a promising avenue toward achieve carbon neutrality.However,addressing the selecti...Electrocatalysis provides an optimal approach for the conversion of carbon dioxide(CO_(2))into high-value chemicals,thereby presenting a promising avenue toward achieve carbon neutrality.However,addressing the selectivity and stability challenges of metal catalysts in electrolytic reduction remains a daunting task.In this study,the electrospinning method is employed to fabricate porous carbon nanofibers loaded with bismuth nanoparticles with the help of in situ pyrolysis.The porous carbon nanofibers as conductive support would facilitate the dispersion of bismuth active sites while inhibiting their aggregation and promoting the mass transfer,thus enhancing their electrocatalytic activity and stability.Additionally,nitrogen doping induces electron delocalization in bismuth atoms through metal-support interactions,thus enabling efficient adsorption of intermediates for improving selectivity based on the theoretical calculation.Consequently,Bi@PCNF-500 exhibits the exceptional selectivity and stability across a wide range of potential windows.Notably,its faradaic efficiency(FE)of formate reaches 92.7%in H-cell and94.9%in flow cell,respectively,with good electrocatalytic stability.The in situ characterization and theoretical calculations elucidate the plausible reaction mechanism to obtain basic rules for designing efficient electrocatalyst.展开更多
At temperature above 1 K, we measured the temperature dependence of the longitudinal and Hall resistivity ρxx,ρxy in the regime of the quantum Hall plateau-to-plateau transitions. The localization exponent v is extr...At temperature above 1 K, we measured the temperature dependence of the longitudinal and Hall resistivity ρxx,ρxy in the regime of the quantum Hall plateau-to-plateau transitions. The localization exponent v is extracted with an approach based on the variable range hopping theory. We find the quantity v ≈ 2.3 at the second Landau level, which is proven to be accurately universal.展开更多
OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the...OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.展开更多
Ultrastrong nanolayered metallic composites are usually subjected to low ductility due to plastic instability during deformation.Here we investigated the shear instability of a newly designed heterogeneous nanolayered...Ultrastrong nanolayered metallic composites are usually subjected to low ductility due to plastic instability during deformation.Here we investigated the shear instability of a newly designed heterogeneous nanolayered Cu/Zr composites by microindentation.The heterogeneity in size was generated by inserting a few thin Cu-Zr bilayers with an individual layer thickness of 2.5-10 nm into the interface region of the Cu/Zr layered composites with an individual layer thickness of 100 nm.The microindentation tests showed that multiple shear bands appeared in the heterogeneous composite with one bilayer,whereas only a single shear band was formed in that with two or three bilayers.Most importantly,the layer strain in the multi-shear band region is much smaller than that in the single-shear band area.For example,the strain of the 100 nm layers within the shear band in the composite with one 10 nm bilayer could reach as low as 2.8,which was less than half of that in the composite with three 10 nm bilayers,i.e.,6.1.These fndings demonstrated that strain delocalization can be achieved through shear band multiplication if an appropriate number of thin bilayers were used as interlayers in the 100 nm Cu/Zr composites.Besides,compared with the homogeneous composite with an individual layer thickness of 100 nm and the bimodal composite which is composed of alternating one 100 nm Cu-Zr bilayer and two 10 nm CuZr bilayers,the heterogeneous composite with one bilayer displayed a higher strength(2.15 GPa)and a favorable resistance to strain localization.展开更多
Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the ...Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic lattice.Herein,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)ions.Theoretically,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge re-delocalization.Benefiting from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)ions.Accordingly,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.展开更多
Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO...Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO4H2O. The present calculations show that the major part of the spin magnetic moment in these two compounds is from Np（V） ions, and the origin of the cation-cation interactions between Np comes from the spin polarization effect within Np-ONv-Np bonds.展开更多
We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the loc...We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the localization length is enhanced by disorder of side sites in the case of strong disorder, but in the case of weak disorder there is a plateau in this dependence. The above behaviour is the conjunct influence of the coupling to the surrounding atoms and the antiresonant effect. We also discuss different effects and their physical origin of different types of disorder in such systems. The numerical results show that coupling with the surrounding atoms can induce either the localization or delocalization effect depending on the values of parameters.展开更多
基金supported by the National Nature Science Foundation of China(Nos.52202335 and 52171227)Natural Science Foundation of Jiangsu Province(No.BK20221137)National Key R&D Program of China(2024YFE0108500).
文摘Wide-temperature applications of sodium-ion batteries(SIBs)are severely limited by the sluggish ion insertion/diffusion kinetics of conversion-type anodes.Quantum-sized transition metal dichalcogenides possess unique advantages of charge delocalization and enrich uncoordinated electrons and short-range transfer kinetics,which are crucial to achieve rapid low-temperature charge transfer and high-temperature interface stability.Herein,a quantum-scale FeS_(2) loaded on three-dimensional Ti_(3)C_(2) MXene skeletons(FeS_(2) QD/MXene)fabricated as SIBs anode,demonstrating impressive performance under wide-temperature conditions(−35 to 65).The theoretical calculations combined with experimental characterization interprets that the unsaturated coordination edges of FeS_(2) QD can induce delocalized electronic regions,which reduces electrostatic potential and significantly facilitates efficient Na+diffusion across a broad temperature range.Moreover,the Ti_(3)C_(2) skeleton reinforces structural integrity via Fe-O-Ti bonding,while enabling excellent dispersion of FeS_(2) QD.As expected,FeS_(2) QD/MXene anode harvests capacities of 255.2 and 424.9 mAh g^(−1) at 0.1 A g^(−1) under−35 and 65,and the energy density of FeS_(2) QD/MXene//NVP full cell can reach to 162.4 Wh kg^(−1) at−35,highlighting its practical potential for wide-temperatures conditions.This work extends the uncoordinated regions induced by quantum-size effects for exceptional Na^(+)ion storage and diffusion performance at wide-temperatures environment.
基金supported by Shandong Provincial Natural Science Foundation,China(ZR2022QE014)Basic Scientific Research Fund for Central Universities(202112018)Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)。
文摘Lithium metal is considered as the most promising anode material for the next generation of secondary batteries due to its high theoretical specific capacity and low potential.However,undesirable parasitic reactions,poor cycling stability and safety concerns could be caused by uncontrolled dendrite and high reactivity of Li metal,which hinder the practical application of Li-metal anode in high-energy rechargeable Li metal batteries(LMBs).Here,a facile way is reported to stabilize Li metal anode by building high lithiophilic Mg-Li-Cu alloy.Due to the delocalization of electrons on the deposited lithium enhanced by Cu self-diffusion into Mg-Li alloy,the growth of lithium dendrites could be inhibited by Mg-Li-Cu alloy.Moreover,the parasitic reactions with electrolyte could be avoided by the Mg-Li-Cu alloy anode.It is noteworthy that the symmetric battery life of Mg-Li-Cu alloy electrodes exceeds 9000 h at 1 m A cm^(-2)and 1 m Ah cm^(-2).The full cell(LiFePO_(4)|Mg-Li-Cu)exhibits a specific capacity of 148.2 m Ah g^(-1),with a capacity retention of 96.4%,at 1 C after 500 cycles.This work not only pave the way for application of flexible alloy anode in highly stable LMBs,but also provides novel strategies for preparation and optimization of Mg alloy.
基金the support from Yunnan Fundamental Research Projects(202301BE070001-029,202401CF070129,202501CF070181)National Natural Science Foundation of China(22209012,22479067)Kunming University of Science and Technology Analysis and Testing Fund Support Project(2023T20220172)。
文摘In order to maximize the advantages of high energy density in Li metal batteries,it is necessary to match cathode materials with high specific capacities.Ni-rich layered oxides have been shown to reversibly embed more Li+during charge and discharge processes due to the increased Ni content in their crystal structure,thereby providing higher energy density.However,a significant challenge associated with Ni-rich layered oxide cathodes is the crossover effect,which arises from the dissolution of Ni^(2+)from the cathode,leading to a rapid decline in battery capacity.Through the delocalization-induced effect of solvent molecules,Ni^(2+)is transformed into a fluorinated transition metal inorganic phase layer,thereby forming a corrosion-resistant Li metal interface.This prevents solvent molecules from being reduced and degraded by Li metal anode.The surface of the Li metal anode exhibits a smooth and flat deposition morphology after long-term cycling.Furthermore,the introduction of Ni^(2+)can enhance the concentration gradient of transition metal ions near the cathode,thereby suppressing the dissolution process of transition metal ions.Even the NCM955 cathode with a mass load of 22 mg cm^(−2)also has great capacity retention after cycling.The Ni^(2+)induced by high electronegative functional groups of solvent under the electron delocalization effect,preventing the Ni ions dissolution of cathode and constructing a corrosion-resistant Li metal interface layer.This work provides new insights into suppressing crossover effects in Li metal batteries with high nickel cathodes.
基金support of the RSF Grant No.24-11-00139(analytics,numerical results,manuscript writing)Daxing Xiong acknowledges the support of the NNSF Grant No.12275116,the NSF Grant No.2021J02051,and the startup fund Grant No.MJY21035For Aleksey A.Kudreyko,this work was supported by the Bashkir StateMedicalUniversity StrategicAcademic Leadership Program(PRIORITY-2030)(analytics).
文摘Molecular dynamics(MD)is a powerful method widely used in materials science and solid-state physics.The accuracy of MD simulations depends on the quality of the interatomic potentials.In this work,a special class of exact solutions to the equations of motion of atoms in a body-centered cubic(bcc)lattice is analyzed.These solutions take the form of delocalized nonlinear vibrational modes(DNVMs)and can serve as an excellent test of the accuracy of the interatomic potentials used in MD modeling for bcc crystals.The accuracy of the potentials can be checked by comparing the frequency response of DNVMs calculated using this or that interatomic potential with that calculated using the more accurate ab initio approach.DNVMs can also be used to train new,more accurate machine learning potentials for bcc metals.To address the above issues,it is important to analyze the properties of DNVMs,which is the main goal of this work.Considering only the point symmetry groups of the bcc lattice,34 DNVMs are found.Since interatomic potentials are not used in finding DNVMs,they are exact solutions for any type of potential.Here,the simplest interatomic potentials with cubic anharmonicity are used to simplify the analysis and to obtain some analytical results.For example,the dispersion relations for small-amplitude phonon modes are derived,taking into account interactions between up to the fourth nearest neighbor.The frequency response of the DNVMs is calculated numerically,and for some DNVMs examples of analytical analysis are given.The energy stored by the interatomic bonds of different lengths is calculated,which is important for testing interatomic potentials.The pros and cons of using DNVMs to test and improve interatomic potentials for metals are discussed.Since DNVMs are the natural vibrational modes of bcc crystals,any reliable interatomic potential must reproduce their properties with reasonable accuracy.
基金National Natural Science Foundation of China,Grant/Award Numbers:22279166,52002157National Institute of Education,Singapore,under its Academic Research Fund,Grant/Award Numbers:RI 1/21 EAH,RI 3/23 EAH+1 种基金China Postdoctoral Science Foundation,Grant/Award Numbers:2022M711686,2023M741471Postgraduate Research&Practice Innovation Program of Jiangsu Province,Grant/Award Number:SJCX24_2512。
文摘The architectural design of redox-active organic molecules and the modulation of their electronic properties significantly influence their application in energy storage systems within aqueous environments.However,these organic molecules often exhibit sluggish reaction kinetics and unsatisfactory utilization of active sites,presenting significant challenges for their practical deployment as electrode materials in aqueous batteries.In this study,we have synthesized a novel organic compound(PTPZ),comprised of a centrally symmetric and fully ladder-type structure,tailored for aqueous proton storage.This unique configuration imparts the PTPZ molecule with high electron delocalization and enhanced structural stability.As an electrode material,PTPZ demonstrates a substantial proton-storage capacity of 311.9mAh g^(-1),with an active group utilization efficiency of up to 89% facilitated by an 8-electron transfer process,while maintaining a capacity retention of 92.89% after 8000 chargingdischarging cycles.Furthermore,in-situ monitoring technologies and various theoretical analyses have pinpointed the associated electrochemical processes of the PTPZ electrode,revealing exceptional redox activity,rapid proton diffusion,and efficient charge transfer.These attributes confer a significant competitive advantage to PTPZ as an anode material for high-performance proton storage devices.Consequently,this work contributes to the rational design of organic electrode materials for the advancement of rechargeable aqueous batteries.
基金supported by the National Natural Science Foundation of China(Nos.T2441002 and 22175186)。
文摘A pair of asymmetric rigid carbazole-benzonitrile-based emitters were synthesized by strategically alternating donor and acceptor groups along the molecular edges.The spin-flip process is accelerated by both the formation of localized and delocalized charge transfer states due to linearly positioned donors and strong spin-orbital coupling between different excitation feature of the lowest singlet and triplet excited states.This molecular architecture results in a remarkable short delayed lifespan of around 100 ns.The application of the two emitters in organic light-emitting diodes(OLEDs)achieves the highest external quantum efficiencies of 13.0%for the green emitter and 9.1%for the sky-blue emitter.Impressively,these devices maintain their high efficiency even at high luminance levels.The sustained efficiency is ascribed to the effective suppression of exciton quenching by substantially shortening delayed lifespan.These findings underscore the practical utility of the molecular design strategy that incorporates alternate donor and acceptor groups at the molecular periphery for shortening delayed fluorescence lifetime,and hold great promise for the development of high-performance OLEDs.
文摘The idea of genetic engineering is introduced into the area of product design to improve the design efficiency. A method towards design process optimization based on the design process gene is proposed through analyzing the correlation between the design process gene and characteristics of the design process. The concept of the design process gene is analyzed and categorized into five categories that are the task specification gene, the concept design gene, the overall design gene, the detailed design gene and the processing design gene in the light of five design phases. The elements and their interactions involved in each kind of design process gene signprocess gene mapping is drawn with its structure disclosed based on its function that process gene.
基金financially supported by the National Natural Science Foundation of China(Nos.51731006,51771093,91860104)the support of the National Key Laboratory for Precision Hot Processing of Metals,Harbin Institute of Technology(Grant No.6142909190104)Fundamental Research Funds for the Central Universities(Grant No.30919011295)。
文摘Polysynthetic twinned(PST)TiAl single crystal possesses great potentials for high-temperature applications due to its excellent combination of strength,ductility and creep resistance.However,a critical property for high-temperature application of such material involving high-temperature fatigue properties remains unknown.Here,the high-temperature high-cycle fatigue performance of PST TiAl single crystal has been studied.The result shows that PST TiAl single crystal can withstand more than 107 cyclic loadings at 975℃ under a stress amplitude of 270 MPa,which is significantly higher than traditional TiAl alloys.Experimental observations and atomistic simulations indicate that the improvement of fatigue resistance is attributed to the plastic strain delocalization in uniform lamellar structure,and the plastic deformation is well-distributed and sufficient in each lamella.Even in theα2 lamella with difficult slippage,a large number of stacking fault structures can be observed.The{c+a}dislocations inα2 tend to dissociate into a Frank partial with b=1/6<2^(-)20^(-)3>,forming a ribbon of I1 fault which ensures the continuity of deformation.
基金supported by a Grant of the Innovation and Technology Commission of Hong Kong(Project number:ITS/461/18)City University of Hong Kong(Project number:9678179).
文摘Transition metal-nitrogen-carbon materials(M-N-Cs),particularly Fe-N-Cs,have been found to be electroactive for accelerating oxygen reduction reaction(ORR)kinetics.Although substantial efforts have been devoted to design Fe-N-Cs with increased active species content,surface area,and electronic conductivity,their performance is still far from satisfactory.Hitherto,there is limited research about regulation on the electronic spin states of Fe centers for Fe-N-Cs electrocatalysts to improve their catalytic performance.Here,we introduce Ti_(3)C_(2) MXene with sulfur terminals to regulate the electronic configuration of FeN_(4) species and dramatically enhance catalytic activity toward ORR.The MXene with sulfur terminals induce the spin-state transition of FeN_(4) species and Fe 3d electron delocalization with d band center upshift,enabling the Fe(II)ions to bind oxygen in the end-on adsorption mode favorable to initiate the reduction of oxygen and boosting oxygen-containing groups adsorption on FeN_(4) species and ORR kinetics.The resulting FeN_(4)-Ti_(3)C_(2)Sx exhibits comparable catalytic performance to those of commercial Pt-C.The developed wearable ZABs using FeN_(4)-Ti_(3)C_(2)Sx also exhibit fast kinetics and excellent stability.This study confirms that regulation of the electronic structure of active species via coupling with their support can be a major contributor to enhance their catalytic activity.
基金supported by the National Natural Science Foundation of China(Nos.21772095,91833306,51873159,91956107,61875090 and 21674049)1311 Talents Program of Nanjing University of Posts and Telecommunications(Dingshan),the Six Talent Plan(No.2016XCL050)+3 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD,No.YX030003)China Postdoctoral Science Foundation(No.2020M671460)Jiangsu Planned Projects for Postdoctoral Research Funds(No.20202137)Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.46030CX17761)。
文摘With excellent color purity(full-width half maximum(FWHM)<40 nm)and high quantum yield,multiresonance(MR)molecules can harvest both singlet and triplet excitons for highly efficient narrowband organic light-emitting diodes(OLEDs)owing to their thermally activated delayed fluorescence(TADF)nature.However,the highly rigid molecular skeleton with the oppositely positioned bo ron and nitrogen in generating MR effects results in the intrinsic difficulties in the solution-processing of MR-OLEDs.Here,we demonstrate a facile strategy to increase the solubility,enhance the efficiencies and modulate emission color of MR-TADF molecules by extending aromatic rings and introducing tert-butyls into the MR backbone.Two MR-TADF emitters with smaller singlet-triplet splitting energies(ΔE~(ST))and larger oscillator strengths were prepared conveniently,and the solution-processed MR-OLEDs were fabricated for the first time,exhibiting efficient bluish-green electroluminescence with narrow FWHM of 32 nm and external quantum efficiency of 16.3%,which are even comparable to the state-of-the-art performances of the vacuum-evaporated devices.These results prove the feasibility of designing efficient solutionprocessible MR molecules,offering important clues in developing high-performance solution-processed MR-OLEDs with high efficiency and color purity.
基金Supported by the National Natural Science Foundation of China under Grant No 90503011.
文摘The quark-antiquark （q^-q） spectrum is studied by solving the Schrōdinger equation in the framework of nonrelativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The interactions between quark and antiquark consist of quadratic colour confinement-exchange, one-gluon-exchange, and Goldstone-boson-exchange potentials.
基金supported by the National Natural Science Foundation of China(Nos.22175108 and 22379086)the Natural Science Foundation of Shandong Province(Nos.ZR2020JQ09 and ZR2022ZD27)Taishan Scholars Program of Shandong Province(tstp20221105)。
文摘Electrocatalysis provides an optimal approach for the conversion of carbon dioxide(CO_(2))into high-value chemicals,thereby presenting a promising avenue toward achieve carbon neutrality.However,addressing the selectivity and stability challenges of metal catalysts in electrolytic reduction remains a daunting task.In this study,the electrospinning method is employed to fabricate porous carbon nanofibers loaded with bismuth nanoparticles with the help of in situ pyrolysis.The porous carbon nanofibers as conductive support would facilitate the dispersion of bismuth active sites while inhibiting their aggregation and promoting the mass transfer,thus enhancing their electrocatalytic activity and stability.Additionally,nitrogen doping induces electron delocalization in bismuth atoms through metal-support interactions,thus enabling efficient adsorption of intermediates for improving selectivity based on the theoretical calculation.Consequently,Bi@PCNF-500 exhibits the exceptional selectivity and stability across a wide range of potential windows.Notably,its faradaic efficiency(FE)of formate reaches 92.7%in H-cell and94.9%in flow cell,respectively,with good electrocatalytic stability.The in situ characterization and theoretical calculations elucidate the plausible reaction mechanism to obtain basic rules for designing efficient electrocatalyst.
基金Supported by the International Partnership Project of Chinese Academy of Sciences, the National Basic Research Programme of China, the Knowledge Innovation Project of Chinese Academy of Sciences, and the National Natural Science Foundation of China under Grant Nos 60121503 and 10604052. We thank Professor H. W. Jiang （UCLA）, Professor R. R. Du （Rice）, Professor D. N. Sheng （CSU）, and Dr Y. Chen （Princeton） for helpful discussions.
文摘At temperature above 1 K, we measured the temperature dependence of the longitudinal and Hall resistivity ρxx,ρxy in the regime of the quantum Hall plateau-to-plateau transitions. The localization exponent v is extracted with an approach based on the variable range hopping theory. We find the quantity v ≈ 2.3 at the second Landau level, which is proven to be accurately universal.
基金supported by the Provincial Innovation and Entrepreneurship Training Program of Jiangsu Province(No.201910319079Y)。
文摘OX_(2)(X=halogen)molecules was studied theoretically.Calculation results show that delocalizedπ_(3)^(6) bonds exist in their electronic structures and O atoms adopt the sp^(2) type of hybridization,which violates the prediction of the valence shell electron pair repulsion theory of sp^(3) type.Delocalization stabilization energy is proposed to measure the contribution of delocalizedπ_(3)^(6) bond to energy decrease and proves to bring extra-stability to the molecule.These phenomena can be summarized as a kind of coordinating effect.
基金fnancially supported by the National Natural Science Foundation of China(No.11872380)the Natural Science Foundation of Hunan Province(Nos.2019JJ50750 and 2020JJ3043)+1 种基金the start-up funding from Central South University,Chinathe Joint Research Found Liaoning-Shenyang National Laboratory for Materials Science(No.2019JH3/3010029)。
文摘Ultrastrong nanolayered metallic composites are usually subjected to low ductility due to plastic instability during deformation.Here we investigated the shear instability of a newly designed heterogeneous nanolayered Cu/Zr composites by microindentation.The heterogeneity in size was generated by inserting a few thin Cu-Zr bilayers with an individual layer thickness of 2.5-10 nm into the interface region of the Cu/Zr layered composites with an individual layer thickness of 100 nm.The microindentation tests showed that multiple shear bands appeared in the heterogeneous composite with one bilayer,whereas only a single shear band was formed in that with two or three bilayers.Most importantly,the layer strain in the multi-shear band region is much smaller than that in the single-shear band area.For example,the strain of the 100 nm layers within the shear band in the composite with one 10 nm bilayer could reach as low as 2.8,which was less than half of that in the composite with three 10 nm bilayers,i.e.,6.1.These fndings demonstrated that strain delocalization can be achieved through shear band multiplication if an appropriate number of thin bilayers were used as interlayers in the 100 nm Cu/Zr composites.Besides,compared with the homogeneous composite with an individual layer thickness of 100 nm and the bimodal composite which is composed of alternating one 100 nm Cu-Zr bilayer and two 10 nm CuZr bilayers,the heterogeneous composite with one bilayer displayed a higher strength(2.15 GPa)and a favorable resistance to strain localization.
基金the financial support of this work by the National Natural Science Foundation of China(No.52034011)the Key R&D Program of Shanxi(No.2019ZDLGY04-05)+2 种基金the National Natural Science Foundation of Shaanxi(No.2019JLZ-01)the Fundamental Research Funds for the Central Universities(No.G2020KY05129)the Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(No.2020-BJ-03)。
文摘Rechargeable Mg-ion batteries(MIBs)have attracted much more attentions by virtue of the high capacity from the two electrons chemistry.However,the reversible Mg^(2+)diffusion in cathode materials is restricted by the strong interactions between the high-polarized bivalent Mg^(2+)ions and anionic lattice.Herein,we design and propose a hetero-structural VO_(2)(R)-VS_(4)cathode,in which the re-delocalized d-electrons can effectively shield the polarity of Mg^(2+)ions.Theoretically,the electrons should spontaneously transfer from VS_(4)to VO_(2)(R)through the interfaces of hetero-structure due to the lower work function value of VS_(4).Furthermore,the internal electrons transfer lead to the electronic injection into VO_(2)(R)from VS_(4)and the partially broken V-V dimers,indicating the presence of lone pair electrons and charge re-delocalization.Benefiting from the shield effect of re-delocalized electrons,and the weakened attraction between cations and O/S anions enables more S^(2-)-S_(2)^(2-)redox groups to participate the electrochemical reactions and compensate the double charge of Mg^(2+)ions.Accordingly,VO_(2)(R)-VS_(4)hetero-structure exhibits a high specific capacity of 554 mA h g^(-1)at 50 mA g^(-1).It is believed that the charge re-delocalization of cathode extremely boost the Mg^(2+)ions migration for the high-capacity of MIBs.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10574048 and 20490210
文摘Ab initio within the full potential linearized augmented plane wave （FP-LAPW） method with the GGA＋U approach is applied to study the electronic structures of two compounds NaK3（NpO2）4（SO4）4（H2O）2 and NaNpO2SO4H2O. The present calculations show that the major part of the spin magnetic moment in these two compounds is from Np（V） ions, and the origin of the cation-cation interactions between Np comes from the spin polarization effect within Np-ONv-Np bonds.
基金Project supported by the State Key Programs for Basic Research of China (Grant Nos. 2005CB623605 and 2006CB921803)the National Natural Science Foundation of China (Grant Nos. 60676056 and 10874071)
文摘We investigate several models of a one-dimensional chain coupling with surrounding atoms to elucidate disorder- induced delocalization in quantum wires, a peculiar behaviour against common wisdom. We show that the localization length is enhanced by disorder of side sites in the case of strong disorder, but in the case of weak disorder there is a plateau in this dependence. The above behaviour is the conjunct influence of the coupling to the surrounding atoms and the antiresonant effect. We also discuss different effects and their physical origin of different types of disorder in such systems. The numerical results show that coupling with the surrounding atoms can induce either the localization or delocalization effect depending on the values of parameters.
