Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metall...Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling,while a facile method to solve this issue is still lacking.In this work,we report an effective,environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable,NaF-rich solid electrolyte interface(SEI)layer on metallic Na via adding a small amount(~3 wt%)of fluorinated graphene(FG)in bulk Na.Inspired by the forging processing,a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes.The Na/FG–Na/FG half cell exhibits a low voltage hysteresis of 110–140 mV over 700 h at a current density up to 5 mA cm^(-2) with an areal capacity as high as 5 mAh cm^(-2).Na–CO_(2) full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g^(-1).Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na.Both experiments and density functional theory(DFT)calculations confirm the formation of the NaF-rich SEI layer.The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.展开更多
Ferroelectric materials are typically made up of various elements.By introducing atomic displacements,[1]such as octahedral tilts/rotations[2,3]or interlayer sliding,[4–7]the positive and negative charge centers can ...Ferroelectric materials are typically made up of various elements.By introducing atomic displacements,[1]such as octahedral tilts/rotations[2,3]or interlayer sliding,[4–7]the positive and negative charge centers can be separated,resulting in spontaneous polarization.Due to their homogeneity,it is difficult to achieve ferroelectricity in elemental materials where opposite charge centers must be generated.展开更多
On the basis of existing research,carbon emission reduction technologies in production,processing,packaging,transportation and storage of the food system were summarized,and their application effects were analyzed.In ...On the basis of existing research,carbon emission reduction technologies in production,processing,packaging,transportation and storage of the food system were summarized,and their application effects were analyzed.In view of the inherent inadequacy of carbon emission reduction technologies in Chinese food system,starting from carbon labeling technologies and ESG system of the food industry,the unsoundness of the carbon emission reduction evaluation system and the high cost of related technology promotion,countermeasures such as strengthening top-level design,encouraging and supporting the development of new carbon emission reduction technologies,and improving carbon emission reduction technology subsidies were proposed by drawing on domestic and international experiences.展开更多
Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry ...Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping,while they fail to match most cathode materials toward highvoltage magnesium batteries. Herein,reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl_(2) additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg^(2+) desolvation barrier for accelerated redox kinetics,while the Mg^(2+)-conducting polymer coating on the Mg surface ensures the facile Mg^(2+) migration and the e ective isolation of electrolytes. As a result,reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover,benefitting from the wide electrochemical window of carbonate electrolytes,high-voltage(> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries.展开更多
The coupling between electric ordering and magnetic ordering in two-dimensional(2D)materials is important for both fundamental research of 2D multiferroics and future development of magnetism-based information storage...The coupling between electric ordering and magnetic ordering in two-dimensional(2D)materials is important for both fundamental research of 2D multiferroics and future development of magnetism-based information storage and operation.Here,we introduce a scheme for realizing a magnetic phase transition through the transition of electric ordering.We take CuMoP_(2)S_(6) monolayer as an example,which is a member of the large 2D transition-metal chalcogen-phosphates family.Based on first-principles calculations,we find that it is a multiferroic with unprecedented characters,namely,it exhibits two different phases:an antiferroelectric-antiferromagnetic phase and a ferroelectric-ferromagnetic phase,in which the electric and magnetic orderings are strongly coupled.Importantly,the electric polarization is out-of-plane,so the magnetism can be readily switched by using the gate electric field.Our finding reveals a series of 2D multiferroics with special magnetoelectric coupling,which hold great promise for experimental realization and practical applications.展开更多
Two-dimensional(2D)van der Waals magnetic materials have promising and versatile electronic and magnetic properties in the 2D limit,indicating a considerable potential to advance spintronic applications.Theoretical pr...Two-dimensional(2D)van der Waals magnetic materials have promising and versatile electronic and magnetic properties in the 2D limit,indicating a considerable potential to advance spintronic applications.Theoretical predictions thus far have not ascertained whether monolayer VCl_(3) is a ferromagnetic(FM)or anti-FM monolayer;this also remains to be experimentally verified.We theoretically investigate the influence of potential factors,including C_(3) symmetry breaking,orbital ordering,epitaxial strain,and charge doping,on the magnetic ground state.Utilizing first-principles calculations,we predict a collinear type-Ⅲ FM ground state in monolayer VCl_(3) with a broken C_(3) symmetry,wherein only the former two of three t_(2g)orbitals(a_(1g),e_(g2)^(π)and e_(g1)^(π))are occupied.The atomic layer thickness and bond angles of monolayer VCl_(3) undergo abrupt changes driven by an orbital ordering switch,resulting in concomitant structural and magnetic phase transitions.Introducing doping to the underlying Cl atoms of monolayer VCl_(3) without C_(3) symmetry simultaneously induces in-and out-of-plane polarizations.This can achieve a multiferroic phase transition if combined with the discovered adjustments of magnetic ground state and polarization magnitude under strain.The establishment of an orbital-ordering driven regulatory mechanism can facilitate deeper exploration and comprehension of magnetic properties of strongly correlated systems in monolayer VCl_(3).展开更多
Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss....Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss.Here,we report a composite Li anode composed(LYF)of metallic Li and trace amounts(1 e2 wt%)of two-dimensional YF_(δ).The lithiophilic nature of YF_(δ) enables its homogeneous dispersion in metallic lithium.The LYF electrode exhibits lower resistance,higher chemical and mechanical stability,and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_(δ) incorporation,which was confirmed by in-situ optical microscope observation.X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_(δ) during cycling.The spontaneous reactions are clarified by density functional theory calculations.A quasisolid-state cell with LYF anode,LiFePO_(4) cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization.The cell shows a high initial discharge capacity of 147 mAh g1 at 0.5℃ at 60℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.展开更多
Emergent Dirac fermion states underlie many intriguing properties of graphene,and the search for them constitutes one strong motivation to explore two-dimensional(2D)allotropes of other elements.Phosphorene,the ultrat...Emergent Dirac fermion states underlie many intriguing properties of graphene,and the search for them constitutes one strong motivation to explore two-dimensional(2D)allotropes of other elements.Phosphorene,the ultrathin layers of black phosphorous,has been a subject of intense investigations recently,and it was found that other group-Va elements could also form 2D layers with similar puckered lattice structure.Here,by a close examination of their electronic band structure evolution,we discover two types of Dirac fermion states emerging in the low-energy spectrum.One pair of(type-I)Dirac points is sitting on high-symmetry lines,while two pairs of(type-II)Dirac points are located at generic k-points,with different anisotropic dispersions determined by the reduced symmetries at their locations.Such fully-unpinned(type-II)2D Dirac points are discovered for the first time.In the absence of spin-orbit coupling(SOC),we find that each Dirac node is protected by the sublattice symmetry from gap opening,which is in turn ensured by any one of three point group symmetries.The SOC generally gaps the Dirac nodes,and for the type-I case,this drives the system into a quantum spin Hall insulator phase.We suggest possible ways to realise the unpinned Dirac points in strained phosphorene.展开更多
基金supported by the National Natural Science Foundation of China(No.51572238)Zhejiang Provincial Natural Science Foundation of China under Grant no.LY19E020013Hunan Provincial Science and Technology Major Project of China(2020GK1014).
文摘Na–CO_(2) batteries recently are emerging as promising energy-storage devices due to the abundance of Na in the earth’s crust and the clean utilization of greenhouse gas CO_(2) .However,similar to metallic Li,metallic Na also suffers from a serious issue of dendrite growth upon repeated cycling,while a facile method to solve this issue is still lacking.In this work,we report an effective,environmentally friendly method to inhibit Na dendrite growth by in situ constructing a stable,NaF-rich solid electrolyte interface(SEI)layer on metallic Na via adding a small amount(~3 wt%)of fluorinated graphene(FG)in bulk Na.Inspired by the forging processing,a uniform Na/FG composite was obtained by melting and repetitive FG-adsorbing/hammering processes.The Na/FG–Na/FG half cell exhibits a low voltage hysteresis of 110–140 mV over 700 h at a current density up to 5 mA cm^(-2) with an areal capacity as high as 5 mAh cm^(-2).Na–CO_(2) full cell with the Na/FG anode is able to sustain a stable cycling of 391 cycles at a limited capacity of 1000 mAh g^(-1).Long cycle life of the cell can be attributed to the protecting effect of the in situ fabricated NaF-rich SEI layer on metallic Na.Both experiments and density functional theory(DFT)calculations confirm the formation of the NaF-rich SEI layer.The inhibition effect of the NaF-rich SEI layer for Na dendrites is verified by in situ optical microscopy observations.
文摘Ferroelectric materials are typically made up of various elements.By introducing atomic displacements,[1]such as octahedral tilts/rotations[2,3]or interlayer sliding,[4–7]the positive and negative charge centers can be separated,resulting in spontaneous polarization.Due to their homogeneity,it is difficult to achieve ferroelectricity in elemental materials where opposite charge centers must be generated.
基金Supported by the Fundamental Research Funds for the Central Universities(CZY23014)Major Project of the National Social Science Foundation(19ZDA085)。
文摘On the basis of existing research,carbon emission reduction technologies in production,processing,packaging,transportation and storage of the food system were summarized,and their application effects were analyzed.In view of the inherent inadequacy of carbon emission reduction technologies in Chinese food system,starting from carbon labeling technologies and ESG system of the food industry,the unsoundness of the carbon emission reduction evaluation system and the high cost of related technology promotion,countermeasures such as strengthening top-level design,encouraging and supporting the development of new carbon emission reduction technologies,and improving carbon emission reduction technology subsidies were proposed by drawing on domestic and international experiences.
基金supported by National Key Research and Development Program (2019YFE0111200)the National Natural Science Foundation of China (51722105)+1 种基金Zhejiang Provincial Natural Science Foundation of China (LR18B030001)the Fundamental Research Funds for the Central Universities and the Fundamental Research Funds for the Central Universities。
文摘Magnesium metal anode holds great potentials toward future high energy and safe rechargeable magnesium battery technology due to its divalent redox and dendrite-free nature. Electrolytes based on Lewis acid chemistry enable the reversible Mg plating/stripping,while they fail to match most cathode materials toward highvoltage magnesium batteries. Herein,reversible Mg plating/stripping is achieved in conventional carbonate electrolytes enabled by the cooperative solvation/surface engineering. Strongly electronegative Cl from the MgCl_(2) additive of electrolyte impairs the Mg…O = C interaction to reduce the Mg^(2+) desolvation barrier for accelerated redox kinetics,while the Mg^(2+)-conducting polymer coating on the Mg surface ensures the facile Mg^(2+) migration and the e ective isolation of electrolytes. As a result,reversible plating and stripping of Mg is demonstrated with a low overpotential of 0.7 V up to 2000 cycles. Moreover,benefitting from the wide electrochemical window of carbonate electrolytes,high-voltage(> 2.0 V) rechargeable magnesium batteries are achieved through assembling the electrode couple of Mg metal anode and Prussian blue-based cathodes. The present work provides a cooperative engineering strategy to promote the application of magnesium anode in carbonate electrolytes toward high energy rechargeable batteries.
基金Supported by the National Key R&D Program of China(Grant No.2019YFE0112000)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LR21A040001)the National Natural Science Foundation of China(Grant No.11974307,12088101,11991060,and U1930402).
文摘The coupling between electric ordering and magnetic ordering in two-dimensional(2D)materials is important for both fundamental research of 2D multiferroics and future development of magnetism-based information storage and operation.Here,we introduce a scheme for realizing a magnetic phase transition through the transition of electric ordering.We take CuMoP_(2)S_(6) monolayer as an example,which is a member of the large 2D transition-metal chalcogen-phosphates family.Based on first-principles calculations,we find that it is a multiferroic with unprecedented characters,namely,it exhibits two different phases:an antiferroelectric-antiferromagnetic phase and a ferroelectric-ferromagnetic phase,in which the electric and magnetic orderings are strongly coupled.Importantly,the electric polarization is out-of-plane,so the magnetism can be readily switched by using the gate electric field.Our finding reveals a series of 2D multiferroics with special magnetoelectric coupling,which hold great promise for experimental realization and practical applications.
基金supported by the National Key Research and Development Program of China(Grant Nos.2018YFE0202700 and 2023YFA1406500)the National Natural Science Foundation of China(Grant Nos.11974422 and 12104504)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB30000000)Fundamental Research Funds for the Central Universities,and Research Funds of Renmin University,China(Grant No.22XNKJ30)supported by the Outstanding Innovative Talents Cultivation Funded Programs 2023 of Renmin University,China。
文摘Two-dimensional(2D)van der Waals magnetic materials have promising and versatile electronic and magnetic properties in the 2D limit,indicating a considerable potential to advance spintronic applications.Theoretical predictions thus far have not ascertained whether monolayer VCl_(3) is a ferromagnetic(FM)or anti-FM monolayer;this also remains to be experimentally verified.We theoretically investigate the influence of potential factors,including C_(3) symmetry breaking,orbital ordering,epitaxial strain,and charge doping,on the magnetic ground state.Utilizing first-principles calculations,we predict a collinear type-Ⅲ FM ground state in monolayer VCl_(3) with a broken C_(3) symmetry,wherein only the former two of three t_(2g)orbitals(a_(1g),e_(g2)^(π)and e_(g1)^(π))are occupied.The atomic layer thickness and bond angles of monolayer VCl_(3) undergo abrupt changes driven by an orbital ordering switch,resulting in concomitant structural and magnetic phase transitions.Introducing doping to the underlying Cl atoms of monolayer VCl_(3) without C_(3) symmetry simultaneously induces in-and out-of-plane polarizations.This can achieve a multiferroic phase transition if combined with the discovered adjustments of magnetic ground state and polarization magnitude under strain.The establishment of an orbital-ordering driven regulatory mechanism can facilitate deeper exploration and comprehension of magnetic properties of strongly correlated systems in monolayer VCl_(3).
基金supported by the National Natural Science Foundation of China (U1909212, U1809217, and 11474249)supported by the U.S. Department of Energy, Office of Basic Energy Science, Division of Materials Sciences and Engineering (Ames Laboratory is operated for the U.S. Department of Energy by Iowa State University under Contract No. DE-AC02-07CH11358)。
基金supported by the National Natural Science Foundation of China(Grant no.51572238,51725102)and Zhejiang Provincial Natural Science Foundation of China(Grant no.LY19E020013).
文摘Lithium metal batteries are regarded as promising alternatives to lithium ion batteries due to their high specific capacity.However,lithium dendrite growth during cycling causes safety problem and rapid capacity loss.Here,we report a composite Li anode composed(LYF)of metallic Li and trace amounts(1 e2 wt%)of two-dimensional YF_(δ).The lithiophilic nature of YF_(δ) enables its homogeneous dispersion in metallic lithium.The LYF electrode exhibits lower resistance,higher chemical and mechanical stability,and longer cycle life compared to bare Li electrode due to uniform Li stripping and plating with YF_(δ) incorporation,which was confirmed by in-situ optical microscope observation.X-ray photoelectron spectroscopy reveals that LiF can in-situ form on the LYF electrode with reactions between Li and YF_(δ) during cycling.The spontaneous reactions are clarified by density functional theory calculations.A quasisolid-state cell with LYF anode,LiFePO_(4) cathode and cathode-supported solid electrolyte layer has been constructed with a soft interface constructed between Li anode and solid electrolyte by in-situ thermal polymerization.The cell shows a high initial discharge capacity of 147 mAh g1 at 0.5℃ at 60℃ and sustains a stable cycling over 50 cycles with the in-situ formed LiF-rich layer and soft interface.
基金supported by NSFC(Grant No.11374009,61574123 and 21373184)the National Key Basic Research Program of China(2012CB825700)+5 种基金SUTD-SRG-EPD2013062Singapore MOE Academic Research Fund Tier 1(SUTD-T1-2015004)A*STAR SERC 122-PSF-0017 and AcRF R-144-000-310-112support by Singapore National Research Foundation under NRF Award No.NRF-NRFF2013-03Special Program for Applied Research on Super Computation of the NSFC-Guangdong Joint Fund(the second phase)support from SR16000 supercomputing resources of the Center for Computational Materials Science,Tohoku University.
文摘Emergent Dirac fermion states underlie many intriguing properties of graphene,and the search for them constitutes one strong motivation to explore two-dimensional(2D)allotropes of other elements.Phosphorene,the ultrathin layers of black phosphorous,has been a subject of intense investigations recently,and it was found that other group-Va elements could also form 2D layers with similar puckered lattice structure.Here,by a close examination of their electronic band structure evolution,we discover two types of Dirac fermion states emerging in the low-energy spectrum.One pair of(type-I)Dirac points is sitting on high-symmetry lines,while two pairs of(type-II)Dirac points are located at generic k-points,with different anisotropic dispersions determined by the reduced symmetries at their locations.Such fully-unpinned(type-II)2D Dirac points are discovered for the first time.In the absence of spin-orbit coupling(SOC),we find that each Dirac node is protected by the sublattice symmetry from gap opening,which is in turn ensured by any one of three point group symmetries.The SOC generally gaps the Dirac nodes,and for the type-I case,this drives the system into a quantum spin Hall insulator phase.We suggest possible ways to realise the unpinned Dirac points in strained phosphorene.
