由于变星具有确定的周光关系,我们可以比较准确地计算出它们的距离,因此它们在银河系结构与形成等天文研究领域里有着重要的作用。Hoffman et al.(2009)把北天变星巡天的4659颗变星分类成5种重要变星,我们从他们给出的星表里整理出了19...由于变星具有确定的周光关系,我们可以比较准确地计算出它们的距离,因此它们在银河系结构与形成等天文研究领域里有着重要的作用。Hoffman et al.(2009)把北天变星巡天的4659颗变星分类成5种重要变星,我们从他们给出的星表里整理出了194颗造父变星(包括确认的和候选体),526颗天琴座RR变星和371颗大熊座W变星。我们把这些整理的三类变星与LAMOST DR3数据进行交叉,匹配出来的有13颗造父变星(包含候选体),78颗天琴座RR变星和83颗大熊座W变星,从而我们可以得到这些匹配出的三类变星的LAMOST提供的金属丰度。从三类变星的金属丰度随距离的分布来看,造父变星(或候选体)在5<R_(GC)<15kpc距离范围内有比较明显的梯度。然而RR变星和WUMa变星的金属丰度分布比较弥散,与距离没有相关性。展开更多
Rechargeable zinc(Zn)metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase(SEI).Although the current strategies...Rechargeable zinc(Zn)metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase(SEI).Although the current strategies assist in suppressing dendritic Zn growth,it is still a challenge to obtain the operation-stability of Zn anode with high Coulombic efficiency(CE)required to implement a sustainable and long-cycling life of Zn metal batteries.In this perspective,we summarize the advantages of the functional gradient interphase(FGI)and try to fundamentally understand the transport behaviors of Zn ions,based on recently an article understanding Zn chemistry.The correlation between the function-orientated design of gradient interphase and key challenges of Zn metal anodes in accelerating Zn2+transport kinetics,improving electrode reversibility,and inhibiting Zn dendrite growth and side reactions was particularly emphasized.Finally,the rational design and innovative directions are provided for the development and application of functional gradient interphase in rechargeable Zn metal battery systems.展开更多
There is an increasingly urgent need to develop cost-effective electrocatalysts with high catalytic activity and stability as alternatives to the traditional Pt/C in catalysts in water electrolysis.In this study,micro...There is an increasingly urgent need to develop cost-effective electrocatalysts with high catalytic activity and stability as alternatives to the traditional Pt/C in catalysts in water electrolysis.In this study,microspheres composed of Mo-doped NiCoP nanoneedles supported on nickel foam were prepared to address this challenge.The results show that the nanoneedles provide sufficient active sites for efficient electron transfer;the small-sized effect and the micro-scale roughness enhance the entry of reactants and the release of hydrogen bubbles;the Mo doping effectively improves the electrocatalytic performance of NiCoP in alkaline media.The catalyst exhibits low hydrogen evolution overpotentials of 38.5 and 217.5 mV at a current density of 10 mA·cm^(-2) and high current density of 500 mA·cm^(-2),respectively,and only 1.978 V is required to achieve a current density of 1000 mA·cm^(-2) for overall water splitting.Density functional theory(DFT)calculations show that the improved hydrogen evolution performance can be explained as a result of the Mo doping,which serves to reduce the interaction between NiCoP and intermediates,optimize the Gibbs free energy of hydrogen adsorption(△G_(*H)),and accelerate the desorption rate of *OH.This study provides a promising solution to the ongoing challenge of designing efficient electrocatalysts for high-current-density hydrogen production.展开更多
The separator is of great significance to alleviate the shuttle effect and dendrite growth of lithium-sulfur batteries.However,most of the current commercial separators cannot meet these requirements well.In this work...The separator is of great significance to alleviate the shuttle effect and dendrite growth of lithium-sulfur batteries.However,most of the current commercial separators cannot meet these requirements well.In this work,a dense metal-organic-framework(MOF)modification layer is in-situ prepared by the assistant of polydopamine on the polypropylene separators.Due to the unique structure and synergistic effect of polydopamine(PDA)and zeolitic imidazolate framework-8(ZIF-8),the functional separator can not only trap the polysulfides effectively but also promote the transport of lithium ions.As a result,the battery assembled with the functional separator exhibits excellent cycle stability.The capacity remains 711 mAh·g^(−1)after 500 cycles at 2 C,and the capacity decay rate is as low as 0.013%per cycle.The symmetrical battery is cycled for 1,000 h at 2 mA·cm^(−2)(2 mAh·cm^(−2))with the plating/stripping overpotential of 20 mV.At the same time,the modification separator shows a higher lithium ion transference number(0.88),better thermal stability and electrolyte wettability than the unmodified separator.展开更多
Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of prac...Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of practical lithium metal batteries.Methods of driving lithium metal to deposit inside the pores of structured lithium metal anodes have always been one of the most concerned issues,especially for highly conductive frameworks.An electrochemical phase field theory with galvanostatic lithium plating process is employed in this work,the mechanism that illustrates the preference of lithium metal to deposit at the top of the framework structure has been revealed,and through the simulation analysis of various regulating strategies,the strategies that can efficiently drive lithium to deposit inside structured pores are summarized.This work presents the theoretical calculation and analysis methods that can be used for the rational design of lithium metal batteries.展开更多
Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D ...Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D framework remains a tough challenge.To achieve a uniform bottom-up Li growth,a scheme involving Ag concentration gradient in 3 D PVDF framework(C-Ag/PVDF)is proposed.Ag nanoparticles with a concentration gradient induce an interface activity gradient in the 3 D framework,and this gradient feature is still maintained during the cycle.As a result,the C-Ag/PVDF framework delivers a long lifespan over 1800 h at a current density of 1 mA cm^(-2) with a capacity of 1 mAh cm^(-2),and shows an ultra-long life(>1300 h)even at a high current density of 4 mA cm^(-2) with a capacity of 4 mAh cm^(-2).The advantage of concentration gradient provides further insights into the optimal design of the 3 D framework for stable Li metal anode.展开更多
A combinatorial high-throughput experiment(HTE)was used to optimize composition and process of nickel-saving cryogenic steel.A gradient temperature heat treatment method with a high linear distribution of heat treatme...A combinatorial high-throughput experiment(HTE)was used to optimize composition and process of nickel-saving cryogenic steel.A gradient temperature heat treatment method with a high linear distribution of heat treatment temperature using customized graphite sleeve direct current heating was used in the combinatorial HTE,which enhanced the richness of the sample library for the single preparation of the 10^(2) level component process variables.Cryogenic steel with excellent mechanical properties was optimized using this combinatorial HTE,and the Ni content was reduced from the traditional 9 to 5.6 wt.%by using Mn instead of Ni.The heterogeneous structure architecture strategy and strengthening and toughening mechanism of the harmonic structure induced by intrinsic heat treatment of additive manufacturing were revealed.Taking the composition process optimization of Ni-saving cryogenic steel as an example,the boosting ability of combinatorial HTE in the research and development of new metal materials was proposed.展开更多
文摘由于变星具有确定的周光关系,我们可以比较准确地计算出它们的距离,因此它们在银河系结构与形成等天文研究领域里有着重要的作用。Hoffman et al.(2009)把北天变星巡天的4659颗变星分类成5种重要变星,我们从他们给出的星表里整理出了194颗造父变星(包括确认的和候选体),526颗天琴座RR变星和371颗大熊座W变星。我们把这些整理的三类变星与LAMOST DR3数据进行交叉,匹配出来的有13颗造父变星(包含候选体),78颗天琴座RR变星和83颗大熊座W变星,从而我们可以得到这些匹配出的三类变星的LAMOST提供的金属丰度。从三类变星的金属丰度随距离的分布来看,造父变星(或候选体)在5<R_(GC)<15kpc距离范围内有比较明显的梯度。然而RR变星和WUMa变星的金属丰度分布比较弥散,与距离没有相关性。
基金the National Key R&D Program of China(Nos.2022YFB3805904 and 2022YFB3805900)the National Natural Science Foundation of China(Nos.22122207 and 21988102)CAS Project for Young Scientists in Basic Research(YSBR-039)。
文摘Rechargeable zinc(Zn)metal batteries have long been plagued by dendrite growth and parasitic reactions due to the absence of a stable Zn-ion conductive solid-electrolyte interphase(SEI).Although the current strategies assist in suppressing dendritic Zn growth,it is still a challenge to obtain the operation-stability of Zn anode with high Coulombic efficiency(CE)required to implement a sustainable and long-cycling life of Zn metal batteries.In this perspective,we summarize the advantages of the functional gradient interphase(FGI)and try to fundamentally understand the transport behaviors of Zn ions,based on recently an article understanding Zn chemistry.The correlation between the function-orientated design of gradient interphase and key challenges of Zn metal anodes in accelerating Zn2+transport kinetics,improving electrode reversibility,and inhibiting Zn dendrite growth and side reactions was particularly emphasized.Finally,the rational design and innovative directions are provided for the development and application of functional gradient interphase in rechargeable Zn metal battery systems.
基金support from the National Natural Science Foundation of China(No.22179077)the National Natural Science Foundation Youth Fund(No.22209104)+3 种基金Shanghai Science and Technology Commission’s“2020 Science and Technology Innovation Action Plan”(No.20511104003)the Natural Science Foundation of Shanghai(No.21ZR1424200)Hebei provincial Department of Science and Technology(No.226Z4404G)Hebei Science Foundation(No.E2021203005).
文摘There is an increasingly urgent need to develop cost-effective electrocatalysts with high catalytic activity and stability as alternatives to the traditional Pt/C in catalysts in water electrolysis.In this study,microspheres composed of Mo-doped NiCoP nanoneedles supported on nickel foam were prepared to address this challenge.The results show that the nanoneedles provide sufficient active sites for efficient electron transfer;the small-sized effect and the micro-scale roughness enhance the entry of reactants and the release of hydrogen bubbles;the Mo doping effectively improves the electrocatalytic performance of NiCoP in alkaline media.The catalyst exhibits low hydrogen evolution overpotentials of 38.5 and 217.5 mV at a current density of 10 mA·cm^(-2) and high current density of 500 mA·cm^(-2),respectively,and only 1.978 V is required to achieve a current density of 1000 mA·cm^(-2) for overall water splitting.Density functional theory(DFT)calculations show that the improved hydrogen evolution performance can be explained as a result of the Mo doping,which serves to reduce the interaction between NiCoP and intermediates,optimize the Gibbs free energy of hydrogen adsorption(△G_(*H)),and accelerate the desorption rate of *OH.This study provides a promising solution to the ongoing challenge of designing efficient electrocatalysts for high-current-density hydrogen production.
基金the Ministry of Science and Technology of the People’s Republic of China(No.2017YFE0127600)the National Natural Science Foundation of China(No.51702247)+3 种基金the Fundamental Research Funds for the Central Universities(No.WUT:2020III023,2020III050,2021IVA123,2021III009)Hainan Provincial Joint Project of Sanya Yazhou Bay Science and Technology City(No.520LH056)Sanya Science and Education Innovation Park of Wuhan University of Technology(No.2020KF0021)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(WUT:2021-ZD-1).
文摘The separator is of great significance to alleviate the shuttle effect and dendrite growth of lithium-sulfur batteries.However,most of the current commercial separators cannot meet these requirements well.In this work,a dense metal-organic-framework(MOF)modification layer is in-situ prepared by the assistant of polydopamine on the polypropylene separators.Due to the unique structure and synergistic effect of polydopamine(PDA)and zeolitic imidazolate framework-8(ZIF-8),the functional separator can not only trap the polysulfides effectively but also promote the transport of lithium ions.As a result,the battery assembled with the functional separator exhibits excellent cycle stability.The capacity remains 711 mAh·g^(−1)after 500 cycles at 2 C,and the capacity decay rate is as low as 0.013%per cycle.The symmetrical battery is cycled for 1,000 h at 2 mA·cm^(−2)(2 mAh·cm^(−2))with the plating/stripping overpotential of 20 mV.At the same time,the modification separator shows a higher lithium ion transference number(0.88),better thermal stability and electrolyte wettability than the unmodified separator.
基金supported by Beijing Natural Science Foundation(JQ20004)National Key Research and Development Program(2021YFB2400300)+1 种基金National Natural Scientific Foundation of China(22109011)the China Postdoctoral Science Foundation(BX20200047,2021M690380)。
文摘Lithium metal anode is one of the most important anode materials for next-generation high-specificenergy secondary batteries.Structured lithium metal anodes have received extensive attention in the development of practical lithium metal batteries.Methods of driving lithium metal to deposit inside the pores of structured lithium metal anodes have always been one of the most concerned issues,especially for highly conductive frameworks.An electrochemical phase field theory with galvanostatic lithium plating process is employed in this work,the mechanism that illustrates the preference of lithium metal to deposit at the top of the framework structure has been revealed,and through the simulation analysis of various regulating strategies,the strategies that can efficiently drive lithium to deposit inside structured pores are summarized.This work presents the theoretical calculation and analysis methods that can be used for the rational design of lithium metal batteries.
基金supported by the Fundamental Research Funds for the Central Universities,China(ZYGX2019Z008)the National Natural Science Foundation of China(52072061)the Open Fund of the Key Laboratory for Renewable Energy,Chinese Academy of Sciences,Beijing Key Laboratory for New Energy Materials and Devices。
文摘Three-dimensional(3 D)frameworks have received much attention as an effective modification strategy for next-generation high-energy-density lithium metal batteries.However,the top-growth mode of lithium(Li)on the 3 D framework remains a tough challenge.To achieve a uniform bottom-up Li growth,a scheme involving Ag concentration gradient in 3 D PVDF framework(C-Ag/PVDF)is proposed.Ag nanoparticles with a concentration gradient induce an interface activity gradient in the 3 D framework,and this gradient feature is still maintained during the cycle.As a result,the C-Ag/PVDF framework delivers a long lifespan over 1800 h at a current density of 1 mA cm^(-2) with a capacity of 1 mAh cm^(-2),and shows an ultra-long life(>1300 h)even at a high current density of 4 mA cm^(-2) with a capacity of 4 mAh cm^(-2).The advantage of concentration gradient provides further insights into the optimal design of the 3 D framework for stable Li metal anode.
基金the financial support of the National KeyR&DProgram of China(No.2021YFB3702401)Major Program of the National Natural Science Foundation of China(No.52293394)the National Natural Science Foundation of China(No.51831002).
文摘A combinatorial high-throughput experiment(HTE)was used to optimize composition and process of nickel-saving cryogenic steel.A gradient temperature heat treatment method with a high linear distribution of heat treatment temperature using customized graphite sleeve direct current heating was used in the combinatorial HTE,which enhanced the richness of the sample library for the single preparation of the 10^(2) level component process variables.Cryogenic steel with excellent mechanical properties was optimized using this combinatorial HTE,and the Ni content was reduced from the traditional 9 to 5.6 wt.%by using Mn instead of Ni.The heterogeneous structure architecture strategy and strengthening and toughening mechanism of the harmonic structure induced by intrinsic heat treatment of additive manufacturing were revealed.Taking the composition process optimization of Ni-saving cryogenic steel as an example,the boosting ability of combinatorial HTE in the research and development of new metal materials was proposed.
