Alkali-metal atomic magnetometers employing longitudinal carrier magnetic field have ultrahigh sensitivity to measure transverse magnetic fields and have been applied in a variety of precise-measurement science and te...Alkali-metal atomic magnetometers employing longitudinal carrier magnetic field have ultrahigh sensitivity to measure transverse magnetic fields and have been applied in a variety of precise-measurement science and technologies.In practice,the magnetometer response is not rigorously proportional to the measured transverse magnetic fields and the existing fundamental analytical model of this magnetometer is effective only when the amplitudes of the measured fields are very small.In this paper,we present a modified analytical model to characterize the practical performance of the magnetometer more definitely.We find out how the longitudinal magnetization of the alkali metal atoms vary with larger transverse fields.The linear-response capacity of the magnetometer is determined by these factors:the amplitude and frequency of the longitudinal carrier field,longitudinal and transverse spin relaxation time of the alkali spins and rotation frequency of the transverse fields.We give a detailed and rigorous theoretical derivation by using the perturbation-iteration method and simulation experiments are conducted to verify the validity and correctness of the proposed modified model.This model can be helpful for measuring larger fields more accurately and configuring a desirable magnetometer with proper linear range.展开更多
With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable ...With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional（2D） organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery（LIB）, lithium sulfur battery（LSB）, lithium air battery（LAB） and sodium ion battery（SIB） are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.展开更多
As the lightest two-dimensional material,monolayer borophene exhibits great potential as electrode materials,but it suffers from stability issues in the free-standing form.Here,the striped-borophene and graphene bilay...As the lightest two-dimensional material,monolayer borophene exhibits great potential as electrode materials,but it suffers from stability issues in the free-standing form.Here,the striped-borophene and graphene bilayer(sB/Gr)is found to be a high-performance anode material for rechargeable alkali-metal ion batteries.The first-principles results show that all the three alkali-metal atoms,Li,Na,and K,can be strongly adsorbed on sB/Gr with ultra-low diffusion barriers than that on pristine borophene/graphene,indicating good charge-discharge rates.Remarkably,high storage capacities are proposed for LIBs(1880 mA·h/g),NIBs(1648 mA·h/g),and KIBs(470 m A·h/g)with relatively small lattice change rate(<2.9%)in the process of alkali-metal atoms intercalations.These intriguing features of sB/Gr make it an excellent choice for batteries.展开更多
The collision of alkali-metal atoms at ultralow temperatures have been studied, The Scattering lengths and the effective range are calculated for 7Li, 23Na, 39K, 87Rb, and 133Cs.
The electronic band stucturec of crystalline Na2KC60, Na2RbC40 and Na2CsC60 are examined using the three-dimensional crystal orbital method. Our calculation results reveal that ground states of all these three alkali-...The electronic band stucturec of crystalline Na2KC60, Na2RbC40 and Na2CsC60 are examined using the three-dimensional crystal orbital method. Our calculation results reveal that ground states of all these three alkali-metal doped fullerides from a metalic conducting phase with a rather narrow molecular crystal-like band stucture and a high density of state near the fermi-level, which indicate a very high Tc for this newly found molecular superconductors. A monotonic relationship is found between our calculated band dispersion ,Fermi-level density of state, and the experimental transition temperature Tc, which is in exceuentt agreemet with the prediction of the BCS model.展开更多
Covalent organic frameworks(COFs)are a class of porous crystalline polymers that have been widely investigated in various fields,including energy storage,photo/electrocatalysis,drug delivery.The covalent-bond intercon...Covalent organic frameworks(COFs)are a class of porous crystalline polymers that have been widely investigated in various fields,including energy storage,photo/electrocatalysis,drug delivery.The covalent-bond interconnection allows COFs extraordinary chemical and thermal stability,and the porous structure ensures a high ion-diffusion coefficient.These merits compensate for the drawbacks of organic electrodes that are easy to dissolve and have low charge conductivity,and promote the development of novel electrode materials with excellent performance,environmental friendliness,and low price.However,the application of COFs also encountered many problems,such as poor electronic conductivity due to the large band gap.Moreover,in some three-dimensional(3D)COFs and stacked two-dimensional(2D)COFs,the huge crystal structure,aligned ultralong channels,and numerous crystal defects usually impede ion transport,and the large molecular weights of COFs generally decrease the specific capacities.These issues are urgently needed to be solved.Here in this review,we summarize the latest progress,core challenges and coping strategies concerning with the use of COFs in alkali-metal ion batteries,discuss the impact of material structure on energy storage,and propose strategies for the construction of high-performance COF-based electrodes.展开更多
It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quan...It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.展开更多
Various internal and external defects present in the perovskite film are one of the main factors that causelow efficiency and stability, and in order to realize high-performance perovskite solar cells, it is necessary...Various internal and external defects present in the perovskite film are one of the main factors that causelow efficiency and stability, and in order to realize high-performance perovskite solar cells, it is necessaryto develop a method to effectively suppress them. In this study, a heterofunctional dopants strategy wasattempted to integrate the effect of alkali metal cations (Rbþ and Kþ) and formate anion (HCOO) throughdoping engineering with alkali-metal formates, i.e., rubidium formate (RbHCOO) and potassium formate(KHCOO). Inclusive physical and photoelectric analysis revealed that doping with a small amount ofalkali-metal formate leads to crystal growth and reduction of grain boundaries, and further passivates orinhibits bulk and surface defects. As a result, the photogenerated charge recombination was reduced andthe charge carrier transport was improved, leading to improved PSC performance. RbHCOO-dopedinverted planar PSCs achieved a PCE of up to 20.41% with long-term stability. Our findings provide away for producing high-quality perovskite films with low defect densities that are essential for realizinghigh-performance PSCs.展开更多
High-order dispersion coefficients C9, C11, C12, and C13 for the ground-state alkali-metals were calculated by combining the 1-dependent model potential of alkali-metal atoms and linear variation method based on B-spl...High-order dispersion coefficients C9, C11, C12, and C13 for the ground-state alkali-metals were calculated by combining the 1-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions. The results were compared.展开更多
In this study, we employed the density functional theory method to simulate Li-, Na- and K-adsorbed boron α1-sheets（al-BSTs）. After optimizing possible structures, we investigated their thermodynamic stabilities, b...In this study, we employed the density functional theory method to simulate Li-, Na- and K-adsorbed boron α1-sheets（al-BSTs）. After optimizing possible structures, we investigated their thermodynamic stabilities, barriers for metal atom diffusion on the substrate, and work functions. The computed results indicate that the work function of α1-BST decreases significantly after the adsorption of Li, Na and K. Furthermore, under high hole coverage, these alkali-metal-adsorbed α1-BSTs have lower work functions than the two-dimensional materials of greatest concern and the commonly used electrode materials Ca and Mg. Therefore, the Li-, Na- and K-adsorbed α1-BSTs are potential low-work-function nanomaterials.展开更多
基金the Hunan Graduate Research and Innovation Project(Grant No.CX2018B009)the Natural Science Foundation of Hunan(Grant No.2018JJ3608)+1 种基金the Research Project of National University of Defense Technology(Grant Nos.ZK170204 and ZZKY-YX-07-02)the National Natural Science Foundation of China(Grant Nos.61671458 and 61701515).
文摘Alkali-metal atomic magnetometers employing longitudinal carrier magnetic field have ultrahigh sensitivity to measure transverse magnetic fields and have been applied in a variety of precise-measurement science and technologies.In practice,the magnetometer response is not rigorously proportional to the measured transverse magnetic fields and the existing fundamental analytical model of this magnetometer is effective only when the amplitudes of the measured fields are very small.In this paper,we present a modified analytical model to characterize the practical performance of the magnetometer more definitely.We find out how the longitudinal magnetization of the alkali metal atoms vary with larger transverse fields.The linear-response capacity of the magnetometer is determined by these factors:the amplitude and frequency of the longitudinal carrier field,longitudinal and transverse spin relaxation time of the alkali spins and rotation frequency of the transverse fields.We give a detailed and rigorous theoretical derivation by using the perturbation-iteration method and simulation experiments are conducted to verify the validity and correctness of the proposed modified model.This model can be helpful for measuring larger fields more accurately and configuring a desirable magnetometer with proper linear range.
基金the financial support from the 973 Programs of China(2013CBA01602)NSFC for Excellent Youth Scholars(51722304)+4 种基金NSFC(21720102002,21574080 and 61306018)Shanghai Committee of Science and Technology(15JC1490500,16JC1400703)and Open Project Program of the State Key Laboratory of Supramolecular Structure and Materials(sklssm201732,Jilin University)State Key Laboratory of Inorganic Synthesis and Preparative Chemistry(2016-08,Jilin University)State Key Laboratory for Mechanical Behavior of Materials(20161803,Xi’an Jiaotong University)
文摘With the increasing demand for large-scale battery systems in electric vehicles（EVs） and smart renewable energy grids, organic materials including small molecules and polymers utilized as electrodes in rechargeable batteries have received increasing attraction. In recent years, two-dimensional（2D） organic materials possessing planar layered architecture exhibit optional chemical modification, high specific surface area as well as unique electrical/magnetic properties, which have been emerging as the promising functional materials for wide applications in optoelectronics, catalysis, sensing, etc. Integrating with high-density redox-active sites and hierarchical porous structure, significant achievements in 2D organic materials as cathode materials for alkali-metal-ion batteries have been witnessed. In this review, the recent progress in synthetic approaches, structure analyses, electrochemical characterizations of 2D organic materials as well as their application in alkali-metal-ion batteries containing lithium ion battery（LIB）, lithium sulfur battery（LSB）, lithium air battery（LAB） and sodium ion battery（SIB） are summarized systematically,and their current challenges including cycling stability and electron conductivity for cathode materials in battery fields are also discussed.
基金Project supported by the National Natural Science Foundation of China(Grant No.12174084)the Scientific and Technological Research Foundation of Hebei Province,China(Grant No.ZD2021065)the Key Program of Natural Science Foundation of Hebei Province,China(Grant No.A2021205024)。
文摘As the lightest two-dimensional material,monolayer borophene exhibits great potential as electrode materials,but it suffers from stability issues in the free-standing form.Here,the striped-borophene and graphene bilayer(sB/Gr)is found to be a high-performance anode material for rechargeable alkali-metal ion batteries.The first-principles results show that all the three alkali-metal atoms,Li,Na,and K,can be strongly adsorbed on sB/Gr with ultra-low diffusion barriers than that on pristine borophene/graphene,indicating good charge-discharge rates.Remarkably,high storage capacities are proposed for LIBs(1880 mA·h/g),NIBs(1648 mA·h/g),and KIBs(470 m A·h/g)with relatively small lattice change rate(<2.9%)in the process of alkali-metal atoms intercalations.These intriguing features of sB/Gr make it an excellent choice for batteries.
文摘The collision of alkali-metal atoms at ultralow temperatures have been studied, The Scattering lengths and the effective range are calculated for 7Li, 23Na, 39K, 87Rb, and 133Cs.
文摘The electronic band stucturec of crystalline Na2KC60, Na2RbC40 and Na2CsC60 are examined using the three-dimensional crystal orbital method. Our calculation results reveal that ground states of all these three alkali-metal doped fullerides from a metalic conducting phase with a rather narrow molecular crystal-like band stucture and a high density of state near the fermi-level, which indicate a very high Tc for this newly found molecular superconductors. A monotonic relationship is found between our calculated band dispersion ,Fermi-level density of state, and the experimental transition temperature Tc, which is in exceuentt agreemet with the prediction of the BCS model.
基金This work was financially supported by the Natural Science Foundation of Jiangsu Province of China(BK20180086).
文摘Covalent organic frameworks(COFs)are a class of porous crystalline polymers that have been widely investigated in various fields,including energy storage,photo/electrocatalysis,drug delivery.The covalent-bond interconnection allows COFs extraordinary chemical and thermal stability,and the porous structure ensures a high ion-diffusion coefficient.These merits compensate for the drawbacks of organic electrodes that are easy to dissolve and have low charge conductivity,and promote the development of novel electrode materials with excellent performance,environmental friendliness,and low price.However,the application of COFs also encountered many problems,such as poor electronic conductivity due to the large band gap.Moreover,in some three-dimensional(3D)COFs and stacked two-dimensional(2D)COFs,the huge crystal structure,aligned ultralong channels,and numerous crystal defects usually impede ion transport,and the large molecular weights of COFs generally decrease the specific capacities.These issues are urgently needed to be solved.Here in this review,we summarize the latest progress,core challenges and coping strategies concerning with the use of COFs in alkali-metal ion batteries,discuss the impact of material structure on energy storage,and propose strategies for the construction of high-performance COF-based electrodes.
基金financially supported by the National Natural Science Foundation of China(No.21174122)Special Funds for Major Basic Research Projects(No.G2011CB606001)Zhejiang Provincial Natural Science Foundation of China(No.Y4110115)
文摘It is reported that alkali-metal borohydrides （MBH4, M = Li, Na and K） are efficient catalysts for ring opening polymerization （ROP） of α-amino acid N-carboxyanhydrides （NCAs）. Polypeptides are prepared in quantitative yields with relatively narrow molecular weight distributions （MWDs = 1.1-1.5） which depend on the reaction temperature. End groups of the produced polypeptide are studied in detail by MALDI-ToF MS, IH-NMR, 13C-NMR, IH-1H COSY and IH-13C HMQC analyses. The results indicate that α-hydroxy-ω-aminotelechelic polypeptides are formed which are suitable for post- polymerization functionalization.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1I1A1A01051961 and 2021R1A2C2010353).
文摘Various internal and external defects present in the perovskite film are one of the main factors that causelow efficiency and stability, and in order to realize high-performance perovskite solar cells, it is necessaryto develop a method to effectively suppress them. In this study, a heterofunctional dopants strategy wasattempted to integrate the effect of alkali metal cations (Rbþ and Kþ) and formate anion (HCOO) throughdoping engineering with alkali-metal formates, i.e., rubidium formate (RbHCOO) and potassium formate(KHCOO). Inclusive physical and photoelectric analysis revealed that doping with a small amount ofalkali-metal formate leads to crystal growth and reduction of grain boundaries, and further passivates orinhibits bulk and surface defects. As a result, the photogenerated charge recombination was reduced andthe charge carrier transport was improved, leading to improved PSC performance. RbHCOO-dopedinverted planar PSCs achieved a PCE of up to 20.41% with long-term stability. Our findings provide away for producing high-quality perovskite films with low defect densities that are essential for realizinghigh-performance PSCs.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10947101 and 11074070, the Science and Technology Foundation of Guizhou Province under Grant Nos. J[201212345 and LKZS[2012]02, the Hunan Provincial Natural Science Foundation under Grant No. 10J J4001, the Special Foundation of Governor of Guizhou Province for Science and Technology and Education Talents under Grant No. [2012]87, the Doctor Foundation of Zunyi Normal College under Grant Nos. 2012BSJJ17 and the Key Support Discipline of Guizhou province under Grant No. [20111275. Ding＇s work is supported by Hunan Provincial Natural Science Foundation under Grant No. 11JJ3014 and the Scientific Research Fund of Hunan Provincial Education Department under Grant No. 11B067
文摘High-order dispersion coefficients C9, C11, C12, and C13 for the ground-state alkali-metals were calculated by combining the 1-dependent model potential of alkali-metal atoms and linear variation method based on B-spline basis functions. The results were compared.
基金Supported by the National Natural Science Foundation of China（Nos.21173072, 21601054）.
文摘In this study, we employed the density functional theory method to simulate Li-, Na- and K-adsorbed boron α1-sheets（al-BSTs）. After optimizing possible structures, we investigated their thermodynamic stabilities, barriers for metal atom diffusion on the substrate, and work functions. The computed results indicate that the work function of α1-BST decreases significantly after the adsorption of Li, Na and K. Furthermore, under high hole coverage, these alkali-metal-adsorbed α1-BSTs have lower work functions than the two-dimensional materials of greatest concern and the commonly used electrode materials Ca and Mg. Therefore, the Li-, Na- and K-adsorbed α1-BSTs are potential low-work-function nanomaterials.
