Due to the increasing demand and wide applications of lithium-ion batteries,higher requirements have been placed on the energy density and safety.Polymer solid-state electrolytes have gained significant popularity due...Due to the increasing demand and wide applications of lithium-ion batteries,higher requirements have been placed on the energy density and safety.Polymer solid-state electrolytes have gained significant popularity due to their excellent interface compatibility and safety.However,their applications have been greatly restricted by the high crystallinity at room temperature,which hinders the transport of lithium ions.Herein,we utilize inorganic tubular fillers with abundant lone-pair atoms to reduce the crystallinity of the polyethylene oxide(PEO)solid-state electrolyte membrane and improve its ionic conductivity at room temperature,enabling stable operation of the battery.The tubular lone-pair-rich inorganic fillers play a key role in providing avenues for both internal and external charge transportation.The surface lone-pair electrons facilitate the dissociation and transport of lithium ions,while the internally tubular electron-rich layer attracts ions into the cavities,further enhancing the ion transport.After 100 cycles at room temperature,the lithium battery loaded with this solid-state electrolyte membrane delivers a specific capacity of 141.6 mAh·g−1,which is 51.3%higher compared to the membrane without the fillers.展开更多
In this work,mechanical alloying of the alternating stacked pure Al and Zn thin foils was accomplished via high-pressure torsion(HPT).In the alloyed Al-Zn system,an exotic phase transformation from hexagonal close-pac...In this work,mechanical alloying of the alternating stacked pure Al and Zn thin foils was accomplished via high-pressure torsion(HPT).In the alloyed Al-Zn system,an exotic phase transformation from hexagonal close-packed(HCP)to face-centered cubic(FCC)was identified.The atomic-scale evolution process and underlying mechanism of phase transformation down to atomic scale are provided by molecular dynamics simulation and high-resolution transmission electron microscopy.The HCP→FCC phase transformation was attributed to the sliding of Shockley partial dislocations generated at the Al-Zn grain boundaries,which resulted in an[2110][011]and(0001)/(111)orientation relationship between the two phases.This work provides a new approach for the in-depth study of the solid phase transformation of Al-Zn alloys and also shed lights on understanding the mechanical properties of the HPT processed Al-Zn alloys.展开更多
因放电产物对有机电解液具有高攻击性,使得锂-氧电池能量效率低和循环稳定性差的问题一直限制着其实际应用.与典型放电产物过氧化锂相比,氢氧化锂(LiOH)具有更好的化学和电化学稳定性.本文通过在碳纸上原位生长嵌有纳米银的花状二氧化...因放电产物对有机电解液具有高攻击性,使得锂-氧电池能量效率低和循环稳定性差的问题一直限制着其实际应用.与典型放电产物过氧化锂相比,氢氧化锂(LiOH)具有更好的化学和电化学稳定性.本文通过在碳纸上原位生长嵌有纳米银的花状二氧化锰作为锂-氧电池的正极(Ag/δ-MnO_(2)@CP),并证明了它能催化LiOH的可逆生成和分解.原位拉曼测试和理论计算表明Ag/δ-MnO_(2)催化放电中间体LiO2*与水分子解离的H+反应最终生成LiOH.以Ag/δ-MnO_(2)@CP为正极的锂-氧电池在潮湿氧气环境下表现出更高的比容量和放电平台.在电流密度为200 mA g^(−1)时,锂-氧电池的过电位仅为0.5 V,在500 mA h g^(−1)的限制比容量下可循环867圈.该工作为研究固相催化剂在锂-氧电池中的作用提供了新的思路,并将促进基于LiOH放电产物的锂-氧电池的实际应用.展开更多
The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan regio...The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan region(BMR)during the warm season from 2014 to 2018.The aim of the project was to understand how dynamical,microphysical and electrical processes interact in severe thunderstorms in the BMR,and how to assimilate lightning data in numerical weather prediction models to improve severe thunderstorm forecasts.The platforms used in the field campaign included the Beijing Lightning Network(BLNET,consisting of 16 stations),2 X-band dual linear polarimetric Doppler radars,and 4 laser raindrop spectrometers.The collaboration also made use of the China Meteorological Administration’s mesoscale meteorological observation network in the Beijing-Tianjin-Hebei region.Although diverse thunderstorm types were documented,it was found that squall lines and multicell storms were the two major categories of severe thunderstorms with frequent lightning activity and extreme rainfall or unexpected local short-duration heavy rainfall resulting in inundations in the central urban area,influenced by the terrain and environmental conditions.The flash density maximums were found in eastern Changping District,central and eastern Shunyi District,and the central urban area of Beijing,suggesting that the urban heat island effect has a crucial role in the intensification of thunderstorms over Beijing.In addition,the flash rate associated with super thunderstorms can reach hundreds of flashes per minute in the central city regions.The super(5%of the total),strong(35%),and weak(60%)thunderstorms contributed about 37%,56%,and 7%to the total flashes in the BMR,respectively.Owing to the close connection between lightning activity and the thermodynamic and microphysical characteristics of the thunderstorms,the lightning flash rate can be used as an indicator of severe weather events,such as hail and short-duration heavy rainfall.Lightning data can also be assimilated into numerical weather prediction models to help improve the forecasting of severe convection and precipitation at the cloud-resolved scale,through adjusting or correcting the thermodynamic and microphysical parameters of the model.展开更多
Regularly assembled structures of nanowires, such as aligned arrays, junctions and interconnected networks, have great potential for the applications in logical circuits, address decoders, photoelectronic devices and ...Regularly assembled structures of nanowires, such as aligned arrays, junctions and interconnected networks, have great potential for the applications in logical circuits, address decoders, photoelectronic devices and transparent electrodes. However, for now it is still lack of effective approaches for constructing nanowire bifurcated junctions and crosslinked networks with ordered orientations and high quality. Herein, we report the controlled growth of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks with well-aligned directions and high crystalline degree by utilizing the proportional lattice match between nanowires and substrates. Taking advantages of the “tip-to-stem splice” assembly of individual nanowires, the precise orientation alignments of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks were successfully realized. The controlled growth mechanism and structural evolution process have been elucidated by detailed atomic structure characterizations and modeling. The highly crystal quality and direct energy bandgap of as-assembled photodetectors based on individual bismuth sulfide nanowires enabled high photoresponsivity and fast switch time under light illumination. The three-terminal devices based on nanowire bifurcated junctions present rapid carrier transport across the junction. The flexible photodetectors based on nanowire crosslinked networks show very minimal decay of photocurrent after long-term bending test. This work may provide new insights for the guided construction and regular assembly of low-dimensional ordered functional nanostructures towards advanced nanotechnologies.展开更多
The fundamental understanding of the mechanism underlying the early stages of crystallization of hexagonal-close-packed(hcp)nanocrystals is crucial for their synthesis with desired properties,but it remains a signific...The fundamental understanding of the mechanism underlying the early stages of crystallization of hexagonal-close-packed(hcp)nanocrystals is crucial for their synthesis with desired properties,but it remains a significant challenge.Here,we report using in situ liquid cell transmission electron microscopy(TEM)to directly capture the dynamic nucleation process and track the real-time growth pathway of hcp Ni nanocrystals at the atomic scale.It is demonstrated that the growth of amorphous-phase-mediated hcp Ni nanocrystals is from the metal-rich liquid phases.In addition,the reshaped preatomic facet development of a single nanocrystal is also imaged.Theoretical calculations further identify the non-classical features of hcp Ni crystallization.These discoveries could enrich the nucleation and growth model theory and provide useful information for the rational design of synthesis pathways of hcp nanocrystals.展开更多
基金financially supported by the National Key R&D Program of China(2019YFA0709200)the National Natural Science Foundation of China(21988102,51772198,21975171)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
基金supported by School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(Nos.DD29100027 and DD45001022)the National Natural Science Foundation of China(No.52002094)+1 种基金Shenzhen Science and Technology Program(Nos.JCYJ20210324121411031,JSGG202108021253804014,and RCBS20210706092218040)the Open Fund of the Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials(No.asem202107).
文摘Due to the increasing demand and wide applications of lithium-ion batteries,higher requirements have been placed on the energy density and safety.Polymer solid-state electrolytes have gained significant popularity due to their excellent interface compatibility and safety.However,their applications have been greatly restricted by the high crystallinity at room temperature,which hinders the transport of lithium ions.Herein,we utilize inorganic tubular fillers with abundant lone-pair atoms to reduce the crystallinity of the polyethylene oxide(PEO)solid-state electrolyte membrane and improve its ionic conductivity at room temperature,enabling stable operation of the battery.The tubular lone-pair-rich inorganic fillers play a key role in providing avenues for both internal and external charge transportation.The surface lone-pair electrons facilitate the dissociation and transport of lithium ions,while the internally tubular electron-rich layer attracts ions into the cavities,further enhancing the ion transport.After 100 cycles at room temperature,the lithium battery loaded with this solid-state electrolyte membrane delivers a specific capacity of 141.6 mAh·g−1,which is 51.3%higher compared to the membrane without the fillers.
基金funded by the National Natural Science Foundation of China(Grant Nos.51905215,U22A20187)the Major Scientific and Technological Innovation Project of Shandong Province of China(Grant No.2019JZZY020111).
文摘In this work,mechanical alloying of the alternating stacked pure Al and Zn thin foils was accomplished via high-pressure torsion(HPT).In the alloyed Al-Zn system,an exotic phase transformation from hexagonal close-packed(HCP)to face-centered cubic(FCC)was identified.The atomic-scale evolution process and underlying mechanism of phase transformation down to atomic scale are provided by molecular dynamics simulation and high-resolution transmission electron microscopy.The HCP→FCC phase transformation was attributed to the sliding of Shockley partial dislocations generated at the Al-Zn grain boundaries,which resulted in an[2110][011]and(0001)/(111)orientation relationship between the two phases.This work provides a new approach for the in-depth study of the solid phase transformation of Al-Zn alloys and also shed lights on understanding the mechanical properties of the HPT processed Al-Zn alloys.
基金financially supported by the High-level Talents’Discipline Construction Fund of Shandong University(31370089963078)the School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(20190037 and 20210028)+3 种基金China Postdoctoral Science Foundation(2019M661276 and 2021T140150)Guangdong Basic and Applied Basic Research Foundation(2019A1515110756)the National Natural Science Foundation of China(52002094)the Open Fund of Guangdong Provincial Key laboratory of Advanced Energy Storage Materials(AESM202107)。
文摘因放电产物对有机电解液具有高攻击性,使得锂-氧电池能量效率低和循环稳定性差的问题一直限制着其实际应用.与典型放电产物过氧化锂相比,氢氧化锂(LiOH)具有更好的化学和电化学稳定性.本文通过在碳纸上原位生长嵌有纳米银的花状二氧化锰作为锂-氧电池的正极(Ag/δ-MnO_(2)@CP),并证明了它能催化LiOH的可逆生成和分解.原位拉曼测试和理论计算表明Ag/δ-MnO_(2)催化放电中间体LiO2*与水分子解离的H+反应最终生成LiOH.以Ag/δ-MnO_(2)@CP为正极的锂-氧电池在潮湿氧气环境下表现出更高的比容量和放电平台.在电流密度为200 mA g^(−1)时,锂-氧电池的过电位仅为0.5 V,在500 mA h g^(−1)的限制比容量下可循环867圈.该工作为研究固相催化剂在锂-氧电池中的作用提供了新的思路,并将促进基于LiOH放电产物的锂-氧电池的实际应用.
基金supported by the National Natural Science Foundation of China(Grant Nos.41630425,41671144074)the Key Research Program of Frontier Science,CAS(Grant No.QYZDJ-SSW-DQC007)the National Key Basic Research Program of China(Grant No.2014CB441401)。
文摘The Dynamical-microphysical-electrical Processes in Severe Thunderstorms and Lightning Hazards(STORM973)project conducted coordinated comprehensive field observations of thunderstorms in the Beijing metropolitan region(BMR)during the warm season from 2014 to 2018.The aim of the project was to understand how dynamical,microphysical and electrical processes interact in severe thunderstorms in the BMR,and how to assimilate lightning data in numerical weather prediction models to improve severe thunderstorm forecasts.The platforms used in the field campaign included the Beijing Lightning Network(BLNET,consisting of 16 stations),2 X-band dual linear polarimetric Doppler radars,and 4 laser raindrop spectrometers.The collaboration also made use of the China Meteorological Administration’s mesoscale meteorological observation network in the Beijing-Tianjin-Hebei region.Although diverse thunderstorm types were documented,it was found that squall lines and multicell storms were the two major categories of severe thunderstorms with frequent lightning activity and extreme rainfall or unexpected local short-duration heavy rainfall resulting in inundations in the central urban area,influenced by the terrain and environmental conditions.The flash density maximums were found in eastern Changping District,central and eastern Shunyi District,and the central urban area of Beijing,suggesting that the urban heat island effect has a crucial role in the intensification of thunderstorms over Beijing.In addition,the flash rate associated with super thunderstorms can reach hundreds of flashes per minute in the central city regions.The super(5%of the total),strong(35%),and weak(60%)thunderstorms contributed about 37%,56%,and 7%to the total flashes in the BMR,respectively.Owing to the close connection between lightning activity and the thermodynamic and microphysical characteristics of the thunderstorms,the lightning flash rate can be used as an indicator of severe weather events,such as hail and short-duration heavy rainfall.Lightning data can also be assimilated into numerical weather prediction models to help improve the forecasting of severe convection and precipitation at the cloud-resolved scale,through adjusting or correcting the thermodynamic and microphysical parameters of the model.
基金This work was supported by the National Key R&D Program(Nos.2017YFA0208200 and 2016YFB0700600)the Fundamental Research Funds for the Central Universities(No.0205-14380219)+2 种基金the Projects of the National Natural Science Foundation of China(NSFC)(Nos.21872069,51761135104,and 21573108)the Natural Science Foundation of Jiangsu Province(No.BK20180008)the High-Level Innovation and Entrepreneurship Project of Jiangsu Province of China.
文摘Regularly assembled structures of nanowires, such as aligned arrays, junctions and interconnected networks, have great potential for the applications in logical circuits, address decoders, photoelectronic devices and transparent electrodes. However, for now it is still lack of effective approaches for constructing nanowire bifurcated junctions and crosslinked networks with ordered orientations and high quality. Herein, we report the controlled growth of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks with well-aligned directions and high crystalline degree by utilizing the proportional lattice match between nanowires and substrates. Taking advantages of the “tip-to-stem splice” assembly of individual nanowires, the precise orientation alignments of Bi2S3 semiconductor nanowire bifurcated junctions and crosslinked networks were successfully realized. The controlled growth mechanism and structural evolution process have been elucidated by detailed atomic structure characterizations and modeling. The highly crystal quality and direct energy bandgap of as-assembled photodetectors based on individual bismuth sulfide nanowires enabled high photoresponsivity and fast switch time under light illumination. The three-terminal devices based on nanowire bifurcated junctions present rapid carrier transport across the junction. The flexible photodetectors based on nanowire crosslinked networks show very minimal decay of photocurrent after long-term bending test. This work may provide new insights for the guided construction and regular assembly of low-dimensional ordered functional nanostructures towards advanced nanotechnologies.
基金supported by the National Natural Science Foundation of China(Nos.22001083,52072323,and 52122211)the“Double-First Class”Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University.J.Y.L.thanks the Research Startup Fund from Harbin Institute of Technology(Shenzhen)with the project number University(No.20210028)the Shenzhen Steady Support Plan(No.GXWD20201230155427003-20200824103000001).
文摘The fundamental understanding of the mechanism underlying the early stages of crystallization of hexagonal-close-packed(hcp)nanocrystals is crucial for their synthesis with desired properties,but it remains a significant challenge.Here,we report using in situ liquid cell transmission electron microscopy(TEM)to directly capture the dynamic nucleation process and track the real-time growth pathway of hcp Ni nanocrystals at the atomic scale.It is demonstrated that the growth of amorphous-phase-mediated hcp Ni nanocrystals is from the metal-rich liquid phases.In addition,the reshaped preatomic facet development of a single nanocrystal is also imaged.Theoretical calculations further identify the non-classical features of hcp Ni crystallization.These discoveries could enrich the nucleation and growth model theory and provide useful information for the rational design of synthesis pathways of hcp nanocrystals.