Magnesium-lithium hybrid batteries(MLHBs)have gained increasing attention due to their combined advantages of rapid ion insertion/extraction cathode and magnesium metal anode.Herein,Sn S_(2)-SPAN hybrid cathode with s...Magnesium-lithium hybrid batteries(MLHBs)have gained increasing attention due to their combined advantages of rapid ion insertion/extraction cathode and magnesium metal anode.Herein,Sn S_(2)-SPAN hybrid cathode with strong C-Sn bond and rich defects is ingeniously constructed to realize Mg^(2+)/Li^(+)co-intercalation.The physical and chemical double-confinement synergistic engineering of sulfurized polyacrylonitrile can suppress the agglomeration of Sn S_(2)nanoparticles and the volume expansion,simultaneously promote charge transfer and enhance structural stability.The introduced abundant sulfur vacancies provide more active sites for Mg^(2+)/Li^(+)co-intercalation.Meanwhile,the beneficial effects of rich sulfur defects and C-Sn bond on enhanced electrochemical properties are further evidenced by density-functional theory(DFT)calculations.Therefore,compared with pristine SnS_(2),SnS_(2)-SPAN cathode displays high specific capacity(218 m Ah g^(-1)at 0.5A g^(-1)over 700 cycles)and ultra-long cycling life(101 m Ah g^(-1)at 5 A g^(-1)up to 28,000 cycles).And a high energy density of 307 Wh kg^(-1)can be realized by the Sn S_(2)-SPAN//Mg pouch cell.Such elaborate and simple design supplies a reference for the exploitation of advanced cathode materials with excellent electrochemical properties for MLHBs.展开更多
Effects of pressure on lattice parameters, electronic, thermodynamic and mechanical properties of the fully ordered Ti_(2)AlNb orthorhombic phase were studied using first-principles calculations based on density funct...Effects of pressure on lattice parameters, electronic, thermodynamic and mechanical properties of the fully ordered Ti_(2)AlNb orthorhombic phase were studied using first-principles calculations based on density functional theory(DFT). The bonding nature for ordering orthorhombic Ti_(2)AlNb was revealed quantitatively through the electronic structure analyzing. The external pressures play limited roles in the elastic anisotropy of the alloy due to the outstanding dynamical and mechanical stabilities under pressure. However, the shear modulus of O phase manifests anisotropic, where {010} shear planes are the easiest planes to cleave among the principal planes under all pressures.The heat capacities, volume expansions and thermal expansion coefficients were calculated using the quasi-harmonic approximation model based on the phonon dispersion curves. Meanwhile, the bulk modulus, Young’s modulus,shear modulus and the hardness are promptly enhanced under pressure. The predicted results give hints to design Ti_(2)AlNb-based alloy as high-pressure applications.展开更多
The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,...The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton(3DIO FCSe-QDs@NC)is elaborately designed for both sulfur cathode and Li metal anode.The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble Li PSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors.Simultaneously,the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites.Taking advantage of these merits,the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability(a low decay rate of 0.014%over 2,000 cycles at 2C).Remarkably,a promising areal capacity of 8.41 mAh cm^(-2)can be achieved at the sulfur loading up to 8.50 mg cm^(-2)with an ultra-low electrolyte/sulfur ratio of 4.1μL mg^(-1).This work paves the bi-serve host design from systematic experimental and theoretical analysis,which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.展开更多
Two-dimensional electride Ca_(2)N has strong electron transfer ability and low work function,which is a potential candidate for hydrogen evolution reaction(HER)catalyst.In this work,based on density functional theory ...Two-dimensional electride Ca_(2)N has strong electron transfer ability and low work function,which is a potential candidate for hydrogen evolution reaction(HER)catalyst.In this work,based on density functional theory calculations,we adopt two strategies to improve the HER catalytic activity of Ca_(2)N monolayer:introducing Ca or N vacancy and doping transition metal atoms(TM,refers to Ti,V,Cr,Mn,Fe,Zr,Nb,Mo,Ru,Hf,Ta and W).Interestingly,the Gibbs free energyΔG_(H*)of Ca_(2)N monolayer after introducing N vacancy is reduced to-0.146 e V,showing good HER catalytic activity.It is highlighted that,the HER catalytic activity of Ca_(2)N monolayer can be further enhanced with TM doping,the Gibbs free energyΔG_(H*)of single Mo and double Mn doped Ca_(2)N are predicted to be 0.119 and 0.139 e V,respectively.The present results will provide good theoretical guidance for the HER catalysis applications of two-dimensional electride Ca_(2)N monolayer.展开更多
Sodium metal batteries are arousing extensive interest owing to their high energy density,low cost and wide resource.However,the practical development of sodium metal batteries is inherently plagued by the severe volu...Sodium metal batteries are arousing extensive interest owing to their high energy density,low cost and wide resource.However,the practical development of sodium metal batteries is inherently plagued by the severe volume expansion and the dendrite growth of sodium metal anode during long cycles under high current density.Herein,a simple electrospinning method is applied to construct the uniformly nitrogen-doped porous carbon fiber skeleton and used as three-dimensional(3D)current collector for sodium metal anode,which has high specific surface area(1,098 m^2/g)and strong binding to sodium metal.As a result,nitrogen-doped carbon fiber current collector shows a low sodium deposition overpotential and a highly stable cyclability for 3,500 h with a high coulombic effciency of 99.9%at 2 mA/cm^2 and 2 mAh/cm^2.Moreover,the full cells using carbon coated sodium vanadium phosphate as cathode and sodium pre-plated nitrogen-doped carbon fiber skeleton as hybrid anode can stably cycle for 300 times.These results illustrate an effective strategy to construct a 3D uniformly nitrogen-doped carbon skeleton based sodium metal hybrid anode without the formation of dendrites,which provide a prospect for further development and research of high performance sodium metal batteries.展开更多
With the development of modern electronics,especially the next generation of wearable electromagnetic interference(EMI)shielding materials requires flexibility,ultrathin,lightweight and robustness to protect electroni...With the development of modern electronics,especially the next generation of wearable electromagnetic interference(EMI)shielding materials requires flexibility,ultrathin,lightweight and robustness to protect electronic devices from radiation pollution.In this work,the flexible and ultrathin dopamine modified MXene@cellulose nanofiber(DM@CNF)composite films with alternate multilayer structure have been developed by a facile vacuum filtration induced self-assembly approach.The multilayered DM@CNF composite films exhibit improved mechanical properties compared with the homogeneous DM/CNF film.By adjusting the layer number,the multilayered DM3@CNF2 composite film exhibits a tensile strength of 48.14 MPa and a toughness of 5.28 MJ·m^(–3) with a thickness about 19μm.Interestingly that,the DM@CNF film with annealing treatment achieves significant improvement in conductivity(up to 17264 S·m^(–1))and EMI properties(SE of 41.90 dB and SSE/t of 10169 dB·cm^(2)·g–1),which still maintains relatively high mechanical properties.It is highlighted that the ultrathin multilayered DM@CNF film exhibits superior EMI shielding performance compared with most of the metal-based,carbon-based and MXene-based shielding materials reported in the literature.These results will offer an appealing strategy to develop the ultrathin and flexible MXene-based materials with excellent EMI shielding performance for the next generation intelligent protection devices.展开更多
Development of the nano-electronics requires materials with both high carrier mobility and a sufficiently large electronic band gap.In this work,by means of ab initio calculations,we have predicted a new 2D Ca2Si mono...Development of the nano-electronics requires materials with both high carrier mobility and a sufficiently large electronic band gap.In this work,by means of ab initio calculations,we have predicted a new 2D Ca2Si monolayer with a quasi-planar hexa-coordinate structure.The geometrical structure,stability and electronic properties of Ca2Si monolayer have been systemically investigated.The Ca2Si monolayer is an indirect semiconductor with band gap of about 0.77 eV,which exhibits stable chemical bonding interactions as well as thermal and dynamic stability.Moreover,the carrier mobility in Ca2Si monolayer is electron dominated with a high electron mobility about 4590.47 cm2×V-1×s-1.It is excited that the 2D Ca2Si monolayer exhibits strong directionally anisotropic carrier mobility,which could effectively facilitate the migration and separation of the generated electron-hole pairs.Our calculations demonstrate that the 2D Ca2Si monolayer is potential for high efficiency solar cells and other nano-electronic applications.展开更多
The potential energy surfaces of CN_(6)O isomers were calculated at the B3LYP/aug-cc-pVDZ level and the key decomposition pathways were calculated at the G3B3 level.The optimum pathway for the decomposition of carbony...The potential energy surfaces of CN_(6)O isomers were calculated at the B3LYP/aug-cc-pVDZ level and the key decomposition pathways were calculated at the G3B3 level.The optimum pathway for the decomposition of carbonyl diazide to OCN_(4)and N2 has a barrier of about 30 kcal mol^(−1).Except for carbonyl diazide,no isomer of CN_(6)O crosses a higher decomposition barrier than 20 kcal mol^(−1).The specific impulse of carbonyl diazide is close to those of RDX(cyclotrimethylene trinitramine),HMX(cyclotetramethylene tetranitramine)and CL-20(hexanitrohexaazaisowurtzitane),and the specific impulses of many other CN_(6)O isomers are greater than that of FTDO([1,2,5]oxadizolo[3,4-4][1,2,3,4]tetrazine-4,6-di-Ndioxide).The CN_(6)O system has a higher combustion temperature than RDX,HMX,CL-20 and FTDO at comparable specific impulses.The detonation velocity and pressure of most of CN_(6)O isomers are lower than that of CL-20.展开更多
基金financially supported by the National Key R&D Program of China(No.2023YFB3809500)National Natural Science Foundation of China(Grant No.51931006,52272240 and U22A20118)+2 种基金the Fundamental Research Funds for the Central Universities of China(Xiamen University:No.20720220074)Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(HRTP-[2022]-22)the“Double-First Class”Foundation of Materials Intelligent Manufacturing Discipline of Xiamen University。
文摘Magnesium-lithium hybrid batteries(MLHBs)have gained increasing attention due to their combined advantages of rapid ion insertion/extraction cathode and magnesium metal anode.Herein,Sn S_(2)-SPAN hybrid cathode with strong C-Sn bond and rich defects is ingeniously constructed to realize Mg^(2+)/Li^(+)co-intercalation.The physical and chemical double-confinement synergistic engineering of sulfurized polyacrylonitrile can suppress the agglomeration of Sn S_(2)nanoparticles and the volume expansion,simultaneously promote charge transfer and enhance structural stability.The introduced abundant sulfur vacancies provide more active sites for Mg^(2+)/Li^(+)co-intercalation.Meanwhile,the beneficial effects of rich sulfur defects and C-Sn bond on enhanced electrochemical properties are further evidenced by density-functional theory(DFT)calculations.Therefore,compared with pristine SnS_(2),SnS_(2)-SPAN cathode displays high specific capacity(218 m Ah g^(-1)at 0.5A g^(-1)over 700 cycles)and ultra-long cycling life(101 m Ah g^(-1)at 5 A g^(-1)up to 28,000 cycles).And a high energy density of 307 Wh kg^(-1)can be realized by the Sn S_(2)-SPAN//Mg pouch cell.Such elaborate and simple design supplies a reference for the exploitation of advanced cathode materials with excellent electrochemical properties for MLHBs.
基金financially supported by the National Natural Science Foundation of China (Nos.50971043 and 51171046)the Research Fund for the Doctoral Program of Higher Education of China (No.20133514110006)+1 种基金the Natural Science Foundation of Fujian Province,China (No.2014J01176)the Program for New Century Excellent Talents in University of Fujian Province,China (No.JA10013)。
文摘Effects of pressure on lattice parameters, electronic, thermodynamic and mechanical properties of the fully ordered Ti_(2)AlNb orthorhombic phase were studied using first-principles calculations based on density functional theory(DFT). The bonding nature for ordering orthorhombic Ti_(2)AlNb was revealed quantitatively through the electronic structure analyzing. The external pressures play limited roles in the elastic anisotropy of the alloy due to the outstanding dynamical and mechanical stabilities under pressure. However, the shear modulus of O phase manifests anisotropic, where {010} shear planes are the easiest planes to cleave among the principal planes under all pressures.The heat capacities, volume expansions and thermal expansion coefficients were calculated using the quasi-harmonic approximation model based on the phonon dispersion curves. Meanwhile, the bulk modulus, Young’s modulus,shear modulus and the hardness are promptly enhanced under pressure. The predicted results give hints to design Ti_(2)AlNb-based alloy as high-pressure applications.
基金financial support from the National Natural Science Foundation of China(Grant Nos.51871188 and 51931006)the Fundamental Research Funds for the Central Universities of China(Xiamen University:Nos.20720200068,20720190007 and 20720220074)+2 种基金Guangdong Basic and Applied Basic Research Foundation(No.2021A1515010139)Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(HRTP-[2022]-22)the“Double-First Class”Foundation of Materials Intelligent Manufacturing Discipline of Xiamen University。
文摘The commercial viability of lithium-sulfur batteries is still challenged by the notorious lithium polysulfides(Li PSs)shuttle effect on the sulfur cathode and uncontrollable Li dendrites growth on the Li anode.Herein,a bi-service host with Co-Fe binary-metal selenide quantum dots embedded in three-dimensional inverse opal structured nitrogen-doped carbon skeleton(3DIO FCSe-QDs@NC)is elaborately designed for both sulfur cathode and Li metal anode.The highly dispersed FCSe-QDs with superb adsorptive-catalytic properties can effectively immobilize the soluble Li PSs and improve diffusion-conversion kinetics to mitigate the polysulfide-shutting behaviors.Simultaneously,the 3D-ordered porous networks integrated with abundant lithophilic sites can accomplish uniform Li deposition and homogeneous Li-ion flux for suppressing the growth of dendrites.Taking advantage of these merits,the assembled Li-S full batteries with 3DIO FCSe-QDs@NC host exhibit excellent rate performance and stable cycling ability(a low decay rate of 0.014%over 2,000 cycles at 2C).Remarkably,a promising areal capacity of 8.41 mAh cm^(-2)can be achieved at the sulfur loading up to 8.50 mg cm^(-2)with an ultra-low electrolyte/sulfur ratio of 4.1μL mg^(-1).This work paves the bi-serve host design from systematic experimental and theoretical analysis,which provides a viable avenue to solve the challenges of both sulfur and Li electrodes for practical Li-S full batteries.
基金supported by the National Natural Science Foundation of China(No.21973012)the Natural Science Foundation of Fujian Province(Nos.2020J01474,2021J06011 and 2020J01351)the"Qishan Scholar"Scientific Research Project of Fuzhou University。
文摘Two-dimensional electride Ca_(2)N has strong electron transfer ability and low work function,which is a potential candidate for hydrogen evolution reaction(HER)catalyst.In this work,based on density functional theory calculations,we adopt two strategies to improve the HER catalytic activity of Ca_(2)N monolayer:introducing Ca or N vacancy and doping transition metal atoms(TM,refers to Ti,V,Cr,Mn,Fe,Zr,Nb,Mo,Ru,Hf,Ta and W).Interestingly,the Gibbs free energyΔG_(H*)of Ca_(2)N monolayer after introducing N vacancy is reduced to-0.146 e V,showing good HER catalytic activity.It is highlighted that,the HER catalytic activity of Ca_(2)N monolayer can be further enhanced with TM doping,the Gibbs free energyΔG_(H*)of single Mo and double Mn doped Ca_(2)N are predicted to be 0.119 and 0.139 e V,respectively.The present results will provide good theoretical guidance for the HER catalysis applications of two-dimensional electride Ca_(2)N monolayer.
基金The authors gratefully acknowledge financial support from the Fundamental Research Funds for the Central Universities of China(No.20720190013)the Guangdong Basic and Applied Basic Research Foundation(Nos.2019A1515011070 and 2019B151502045)the National Natural Science Foundation of China(Nos.51972351 and 51802361).
文摘Sodium metal batteries are arousing extensive interest owing to their high energy density,low cost and wide resource.However,the practical development of sodium metal batteries is inherently plagued by the severe volume expansion and the dendrite growth of sodium metal anode during long cycles under high current density.Herein,a simple electrospinning method is applied to construct the uniformly nitrogen-doped porous carbon fiber skeleton and used as three-dimensional(3D)current collector for sodium metal anode,which has high specific surface area(1,098 m^2/g)and strong binding to sodium metal.As a result,nitrogen-doped carbon fiber current collector shows a low sodium deposition overpotential and a highly stable cyclability for 3,500 h with a high coulombic effciency of 99.9%at 2 mA/cm^2 and 2 mAh/cm^2.Moreover,the full cells using carbon coated sodium vanadium phosphate as cathode and sodium pre-plated nitrogen-doped carbon fiber skeleton as hybrid anode can stably cycle for 300 times.These results illustrate an effective strategy to construct a 3D uniformly nitrogen-doped carbon skeleton based sodium metal hybrid anode without the formation of dendrites,which provide a prospect for further development and research of high performance sodium metal batteries.
基金supported by the National Key Research and Development Program of China(No.2022YFB3807200)the National Natural Science Foundation of China(Nos.52201022 and 21973012)+1 种基金the Natural Science Foundation of Fujian Province(Nos.2020J01474,2021J06011,and 2020J01351)the“Qishan Scholar”Scientific Research Startup Project of Fuzhou University.
文摘With the development of modern electronics,especially the next generation of wearable electromagnetic interference(EMI)shielding materials requires flexibility,ultrathin,lightweight and robustness to protect electronic devices from radiation pollution.In this work,the flexible and ultrathin dopamine modified MXene@cellulose nanofiber(DM@CNF)composite films with alternate multilayer structure have been developed by a facile vacuum filtration induced self-assembly approach.The multilayered DM@CNF composite films exhibit improved mechanical properties compared with the homogeneous DM/CNF film.By adjusting the layer number,the multilayered DM3@CNF2 composite film exhibits a tensile strength of 48.14 MPa and a toughness of 5.28 MJ·m^(–3) with a thickness about 19μm.Interestingly that,the DM@CNF film with annealing treatment achieves significant improvement in conductivity(up to 17264 S·m^(–1))and EMI properties(SE of 41.90 dB and SSE/t of 10169 dB·cm^(2)·g–1),which still maintains relatively high mechanical properties.It is highlighted that the ultrathin multilayered DM@CNF film exhibits superior EMI shielding performance compared with most of the metal-based,carbon-based and MXene-based shielding materials reported in the literature.These results will offer an appealing strategy to develop the ultrathin and flexible MXene-based materials with excellent EMI shielding performance for the next generation intelligent protection devices.
基金Supported by the National Key Research and Development Program of China(No.2017YFB0701700)the National Natural Science Foundation of China(No.21973012)the Natural Science Foundation of Fujian Province(No.2016J05003)。
文摘Development of the nano-electronics requires materials with both high carrier mobility and a sufficiently large electronic band gap.In this work,by means of ab initio calculations,we have predicted a new 2D Ca2Si monolayer with a quasi-planar hexa-coordinate structure.The geometrical structure,stability and electronic properties of Ca2Si monolayer have been systemically investigated.The Ca2Si monolayer is an indirect semiconductor with band gap of about 0.77 eV,which exhibits stable chemical bonding interactions as well as thermal and dynamic stability.Moreover,the carrier mobility in Ca2Si monolayer is electron dominated with a high electron mobility about 4590.47 cm2×V-1×s-1.It is excited that the 2D Ca2Si monolayer exhibits strong directionally anisotropic carrier mobility,which could effectively facilitate the migration and separation of the generated electron-hole pairs.Our calculations demonstrate that the 2D Ca2Si monolayer is potential for high efficiency solar cells and other nano-electronic applications.
基金partially supported by the National Natural Science Foundation of China(no.51171046,21303133 and 21403162).
文摘The potential energy surfaces of CN_(6)O isomers were calculated at the B3LYP/aug-cc-pVDZ level and the key decomposition pathways were calculated at the G3B3 level.The optimum pathway for the decomposition of carbonyl diazide to OCN_(4)and N2 has a barrier of about 30 kcal mol^(−1).Except for carbonyl diazide,no isomer of CN_(6)O crosses a higher decomposition barrier than 20 kcal mol^(−1).The specific impulse of carbonyl diazide is close to those of RDX(cyclotrimethylene trinitramine),HMX(cyclotetramethylene tetranitramine)and CL-20(hexanitrohexaazaisowurtzitane),and the specific impulses of many other CN_(6)O isomers are greater than that of FTDO([1,2,5]oxadizolo[3,4-4][1,2,3,4]tetrazine-4,6-di-Ndioxide).The CN_(6)O system has a higher combustion temperature than RDX,HMX,CL-20 and FTDO at comparable specific impulses.The detonation velocity and pressure of most of CN_(6)O isomers are lower than that of CL-20.
