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
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
Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer a...Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.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
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
Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals ...Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals （Ir, Pt, and Au） and 4d metals （Ru, Rh, and Pd） were prepared and capped with ethynylphenylacetylene and the impacts of the number of metal d electrons on the nanoparticle optoelectronic properties were examined. Both FTIR and photoluminescence measurements indicate that intraparticle charge delocalization was en- hanced with the increase of the number of d electrons in the same period with palladium being an exception.展开更多
The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds w...The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).展开更多
Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was c...Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.展开更多
Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trif...Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trifluorostyrenes(Y-TFS's). A series of previously unavailable Y-TFS's were thus obtained.展开更多
We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transpo...We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transport dynamics in the two-photon CCA exhibits the entanglement-enhanced two-photon delocalization phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.展开更多
The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improve...The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.展开更多
Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish tran...Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.展开更多
A unique feature of non-Hermitian systems is the extreme sensitivity of the eigenspectrum to boundary conditions with the emergence of the non-Hermitian skin effect (NHSE). A NHSE originates from the point-gap topolog...A unique feature of non-Hermitian systems is the extreme sensitivity of the eigenspectrum to boundary conditions with the emergence of the non-Hermitian skin effect (NHSE). A NHSE originates from the point-gap topology of complex eigenspectrum, where an extensive number of eigenstates are anomalously localized at the boundary driven by nonreciprocal dissipation. Two different approaches to create localization are disorder and flat-band spectrum, and their interplay can lead to the anomalous inverse Anderson localization, where the Bernoulli anti-symmetric disorder induces mobility in a full-flat band system in the presence of Aharonov−Bohm (AB) Cage. In this work, we study the localization−delocalization transitions due to the interplay of the point-gap topology, flat band and correlated disorder in the one-dimensional rhombic lattice, where both its Hermitian and non-Hermitian structures show AB cage in the presence of magnetic flux. Although it remains the coexistence of localization and delocalization for the Hermitian rhombic lattice in the presence of the random anti-symmetric disorder, it surprisingly becomes complete delocalization, accompanied by the emergence of NHSE. To further study the effects from the Bernoulli anti-symmetric disorder, we found the similar NHSE due to the interplay of the point-gap topology, correlated disorder and flat bands. Our anomalous localization−delocalization property can be experimentally tested in the classical physical platform, such as electrical circuit.展开更多
Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free L...Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free Li^(+)and improving the Li^(+)diffusion kinetics will effectively enhance the cell performance.Here,Mo-based MXene heterostructure(MoS_(2)@Mo_(2)C)was developed by partial vulcanization of Mo_(2)C MXene,in which the introduction of similar valence S into Mo-based MXene(Mo_(2)C)can create an electron delocalization effect.Through theoretical simulations and electrochemical characterisation,it is demonstrated that the MoS_(2)@Mo_(2)C heterojunction can effectively promote ion desolvation,increase the amount of free Li^(+),and accelerate Li^(+)transport for more efficient polysulfide conversion.In addition,the MoS_(2)@Mo_(2)C material is also capable of accelerating the oxidation and reduction of polysulfides through its sufficient defects and vacancies to further enhance the catalytic efficiency.Consequently,the Li-S battery with the designed MoS_(2)@Mo_(2)C electrocatalyst performed for 500 cycles at 1 C and still maintained the ideal capacity(664.7 mAh·g^(−1)),and excellent rate performance(567.6 mAh·g^(−1)at 5 C).Under the extreme conditions of high loading,the cell maintained an excellent capacity of 775.6 mAh·g^(−1)after 100 cycles.It also retained 838.4 mAh·g^(−1)for 70 cycles at a low temperature of 0℃,and demonstrated a low decay rate(0.063%).These results indicate that the delocalized electrons effectively accelerate the catalytic conversion of lithium polysulfide,which is more practical for enhancing the behaviour of Li-S batteries.展开更多
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
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
In our first Paper,we proposed a new QCD model to deal with hadron interaction.The key ingredients of this model are quark delocalization and color screening.The quarkdelocalizafion is modelled from electron delocaliz...In our first Paper,we proposed a new QCD model to deal with hadron interaction.The key ingredients of this model are quark delocalization and color screening.The quarkdelocalizafion is modelled from electron delocalization in molecular physics and the colorscreening is inspirited by the lattice QCD calculations.In this way we obtained the nu-clear intermediate range attraction and the qualitative fit of N—N phase shifts.Following the quark potential model,the quark wave function of a single baryon ischosen to be a Gaussian展开更多
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National Natural Science Foundation of China,Grant/Award Numbers:22162009,32360236。
文摘Investigating the activation of the persulfate process through heterogeneous carbonaceous catalysts to expedite the reduction of uranyl ions(U(Ⅵ))is imperative.The primary hurdle involves understanding the transfer and distribution of photogenerated carriers during the reduction process in this intricate system and deciphering the role of activated groups in promoting reduction efficiency.In this study,we strategically regulate the structure of polymeric carbon nitride to promote the N-doped state,thereby facilitating delocalization electron enrichment.The resulting active sites effectively activate peroxyl disulfate(PDS),generating radicals that expedite the selective reduction of U(VI).This strategic approach mitigates the inherent disadvantage of the short half-life of free radicals in persulfate-based advanced oxidation processes.As a consequence of our endeavors and with the simultaneous presence of PDS and hydrogen peroxide,we achieve an exceptional photoreduction efficiency of 100%within a remarkably short period of 20 min.This breakthrough presents a high-efficiency application with significant potential for addressing the pollution associated with uranylcontaining wastewater.Our findings not only contribute to the fundamental understanding of AOPs but also offer a practical solution with implications for environmental remediation.
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.
基金supported,in part,by the National Science Foundation(DMR-1409396 and CHE-1710408)carried out at the National Center for Electron Microscopy and Molecular Foundry of Lawrence Berkeley National Laboratory,which is supported by the US Department of Energy
文摘Intraparticle charge delocalization occurs when metal nanoparticles are functionalized with organic capping ligands through conjugated rnetal-ligand interfacial bonds. In this study, metal nanoparticles of 5d metals （Ir, Pt, and Au） and 4d metals （Ru, Rh, and Pd） were prepared and capped with ethynylphenylacetylene and the impacts of the number of metal d electrons on the nanoparticle optoelectronic properties were examined. Both FTIR and photoluminescence measurements indicate that intraparticle charge delocalization was en- hanced with the increase of the number of d electrons in the same period with palladium being an exception.
基金financially supported by the National Key Research and Development Program of China(Grant No.2018YFA0702100)the Joint Funds of the National Natural Science Foundation of China+1 种基金the Chinese Academy of Sciences’Large-Scale Scientific Facility(Grant No.U1932106)the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)。
文摘The misfit layer compound(SnS)_(1.2)(TiS_(2))_(2)is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure.However,the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying.Here,we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons.This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range.It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons,indicating that it independently modulates phonon and charge transport properties.These effects collectively give rise to a maximum ZT of 0.3 at 720 K.In addition,we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound(SnS)_(1.2)(TiS_(2))_(2).
基金supported by the National Research Foundation of Korea(NRF)grants funded by the Korea government(MSIT)(2022R1F1A1065586,2019R1A6A1A11053838)the GIST Research Institute(GRI)APRI grant funded by the GIST in 2022.
文摘Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized previously.However,the driving force that leads to this reduction was not clearly understood.In this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ composites.We demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination process.The driving force for this deactivation was determined to be the improved interchain hole delocalization between the polymers.An enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)spectroscopy.In particular,increased splitting between the polaron PIA bands was noted.Moreover,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.
基金Supported by National Natural Science Foundation of China
文摘Palladium-catalyzed coupling of trifluorovinylzinc reagent with substituted aryl halides Y-C_6H_4-X (Y=p-NO_2, p-and m-COOMe, p-COOH, p-CONH_2, p- and m-CN; X=Br, I, Cl) provides a synthetic method for α, β, β-trifluorostyrenes(Y-TFS's). A series of previously unavailable Y-TFS's were thus obtained.
基金Supported by the National Basic Research Program of China under Grant No 2013CB921804the National Natural Science Foundation of China under Grant Nos 11375060 and 11434011
文摘We study the transport properties of two entangled photons which are initially injected into two nearest-neighbor coupling cavities in an one-dimensional coupled-cavity array （CCA）. It is found that photonic transport dynamics in the two-photon CCA exhibits the entanglement-enhanced two-photon delocalization phenomenon. It is shown that the CCA can realize the localization-to-delocalization transition for two entangled photons.
基金supported by the National Natural Science Foundation of China(52225104 and 52071084)the Key Research and Development Program of Shanxi Province(2024CY2-GJHX-65)+1 种基金“Shuguang Program”supported by the Shanghai Education Development Foundation and Shanghai Municipal Education Commission(20SG03)Science and Technology Commission of Shanghai Municipality(22520710600)。
文摘The introduction of foreign metals with a higher oxophilicity represents a promising strategy to promote water dissociation and in turn kinetics of alkaline hydrogen evolution reaction(HER).However,the further improvement of HER activity is limited by the unfavorable interaction of hydroxyl generated by the dissociation of water with active sites.Herein,we propose a strategy of alkaline earth metal cations-driven electron delocalization to elaborately tailor the binding of hydroxyl with the active sites.Taking FeNiMg-layered double hydroxides(FeNiMg-LDH)as a prototypical example,the combined operando spectroscopy analysis and theoretical calculations show that the introduction of Mg cations in solid-solution phase can create a local electronic field and delocalize the electron between Fe and adsorbed hydroxyl,resulting in an optimization of hydroxyl binding strength.Accordingly,FeNiMg-LDH lowers the overpotentials to deliver 10 mA cm−2 in alkaline electrolyte by 39 and 64 mV,compared to FeNi-LDH and Ni-LDH catalysts,respectively.This work sheds new light on the rational design of advanced HER electrocatalyst for alkaline water electrolysis.
基金the financial support from the National Key Projects for Fundamental Research and Development of China(2021YFA1500803)the National Natural Science Foundation of China(No.22209190)+2 种基金the Central China Normal University(2020CXZZ023)the Young Elite Scientists Sponsorship Program by CAST(2023QNRC001)the Beijing Natural Science Foundation(2222081).S.O.appreciates the financial support from the“Guizi Scholar”Program of Central China Normal University and the fellowship of China Postdoctoral Science Foundation(No.GZC20241766,2024M753304).
文摘Photocatalytic hydrogen evolution based on the use of carbon nitride(CN)catalyst offers a sustainable route to convert solar energy into hydrogen energy;however,its activity is severely restricted by the sluggish transfer of photogenerated charges.Herein,we report a novel approach involving boron(B)dopinginducedπ-electron delocalization in CN for efficient hydrogen(H2)evolution.The as-prepared B-dopedCN(BCN)catalyst presented an 8.6-fold enhancement in the H2-evolution rate(7924.0μmol h^(−1)g^(−1))under visible-light irradiation compared with pristine CN,which corresponded to an apparent quantum yield(AQY)of 14.5%at 405 nm.Experimental analysis and density functional theory(DFT)calculations demonstrated that B doping inducedπ-electron delocalization in conjugated CN rings to generate a new intermediate state within the band gap to provide a new transfer path for visible-light utilization,thus achieving the high separation and transfer of photoinduced carriers.This work provides a new approach to adjust the electronic structure of CN-like conjugated polymer semiconductors for efficient catalytic energy conversion.
基金T.L.acknowledges the support from the Fundamental Research Funds for the Central Universities(Grant No.2023ZYGXZR020)the Introduced Innovative Team Project of Guangdong Pearl River Talents Program(Grant No.2021ZT09Z109)the Startup Grant of South China University of Technology(Grant No.20210012).
文摘A unique feature of non-Hermitian systems is the extreme sensitivity of the eigenspectrum to boundary conditions with the emergence of the non-Hermitian skin effect (NHSE). A NHSE originates from the point-gap topology of complex eigenspectrum, where an extensive number of eigenstates are anomalously localized at the boundary driven by nonreciprocal dissipation. Two different approaches to create localization are disorder and flat-band spectrum, and their interplay can lead to the anomalous inverse Anderson localization, where the Bernoulli anti-symmetric disorder induces mobility in a full-flat band system in the presence of Aharonov−Bohm (AB) Cage. In this work, we study the localization−delocalization transitions due to the interplay of the point-gap topology, flat band and correlated disorder in the one-dimensional rhombic lattice, where both its Hermitian and non-Hermitian structures show AB cage in the presence of magnetic flux. Although it remains the coexistence of localization and delocalization for the Hermitian rhombic lattice in the presence of the random anti-symmetric disorder, it surprisingly becomes complete delocalization, accompanied by the emergence of NHSE. To further study the effects from the Bernoulli anti-symmetric disorder, we found the similar NHSE due to the interplay of the point-gap topology, correlated disorder and flat bands. Our anomalous localization−delocalization property can be experimentally tested in the classical physical platform, such as electrical circuit.
基金supported by the National Natural Science Foundation of China(No.U1710252)the Natural Science Foundation of Jiangsu Province(BK.20210130)+3 种基金Innovative and Entrepreneurial Doctor in Jiangsu Province(No.JSSCBS20211428)China Postdoctoral Science Foundation(No.2023M731084)Shanghai Sailing Program of China(No.23YF1408900)the Fundamental Research Funds for the Central Universities(No.JKD01231701).
文摘Lithium-sulfur(Li-S)batteries mainly rely on the reversible electrochemical reaction of between lithium ions(Li^(+))and sulfur species to achieve energy storage and conversion,therefore,increasing the number of free Li^(+)and improving the Li^(+)diffusion kinetics will effectively enhance the cell performance.Here,Mo-based MXene heterostructure(MoS_(2)@Mo_(2)C)was developed by partial vulcanization of Mo_(2)C MXene,in which the introduction of similar valence S into Mo-based MXene(Mo_(2)C)can create an electron delocalization effect.Through theoretical simulations and electrochemical characterisation,it is demonstrated that the MoS_(2)@Mo_(2)C heterojunction can effectively promote ion desolvation,increase the amount of free Li^(+),and accelerate Li^(+)transport for more efficient polysulfide conversion.In addition,the MoS_(2)@Mo_(2)C material is also capable of accelerating the oxidation and reduction of polysulfides through its sufficient defects and vacancies to further enhance the catalytic efficiency.Consequently,the Li-S battery with the designed MoS_(2)@Mo_(2)C electrocatalyst performed for 500 cycles at 1 C and still maintained the ideal capacity(664.7 mAh·g^(−1)),and excellent rate performance(567.6 mAh·g^(−1)at 5 C).Under the extreme conditions of high loading,the cell maintained an excellent capacity of 775.6 mAh·g^(−1)after 100 cycles.It also retained 838.4 mAh·g^(−1)for 70 cycles at a low temperature of 0℃,and demonstrated a low decay rate(0.063%).These results indicate that the delocalized electrons effectively accelerate the catalytic conversion of lithium polysulfide,which is more practical for enhancing the behaviour of Li-S batteries.
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Project supported partly by DOE of US and partly by NSF of China.
文摘In our first Paper,we proposed a new QCD model to deal with hadron interaction.The key ingredients of this model are quark delocalization and color screening.The quarkdelocalizafion is modelled from electron delocalization in molecular physics and the colorscreening is inspirited by the lattice QCD calculations.In this way we obtained the nu-clear intermediate range attraction and the qualitative fit of N—N phase shifts.Following the quark potential model,the quark wave function of a single baryon ischosen to be a Gaussian
