To ensure the long-term safety and stability of bridge pile foundations in permafrost regions,it is necessary to investigate the rheological effects on the pile tip and pile side bearing capacities.The creep character...To ensure the long-term safety and stability of bridge pile foundations in permafrost regions,it is necessary to investigate the rheological effects on the pile tip and pile side bearing capacities.The creep characteristics of the pile-frozen soil interface are critical for determining the long-term stability of permafrost pile foundations.This study utilized a self-developed large stress-controlled shear apparatus to investigate the shear creep characteristics of the frozen silt-concrete interface,and examined the influence of freezing temperatures(−1,−2,and−5°C),contact surface roughness(0,0.60,0.75,and 1.15 mm),normal stress(50,100,and 150 kPa),and shear stress on the creep characteristics of the contact surface.By incorporating the contact surface’s creep behavior and development trends,we established a creep constitutive model for the frozen silt-concrete interface based on the Nishihara model,introducing nonlinear elements and a damage factor.The results revealed significant creep effects on the frozen silt-concrete interface under constant load,with creep displacement at approximately 2-15 times the instantaneous displacement and a failure creep displacement ranging from 6 to 8 mm.Under different experimental conditions,the creep characteristics of the frozen silt-concrete interface varied.A larger roughness,lower freezing temperatures,and higher normal stresses resulted in a longer sample attenuation creep time,a lower steady-state creep rate,higher long-term creep strength,and stronger creep stability.Building upon the Nishihara model,we considered the influence of shear stress and time on the viscoelastic viscosity coefficient and introduced a damage factor to the viscoplasticity.The improved model effectively described the entire creep process of the frozen silt-concrete interface.The results provide theoretical support for the interaction between pile and soil in permafrost regions.展开更多
As a key material for lithium metal batteries(LMBs),lithium metal is one of the most promising anode materials to break the bottleneck of battery energy density and a commonly used active material for reference electr...As a key material for lithium metal batteries(LMBs),lithium metal is one of the most promising anode materials to break the bottleneck of battery energy density and a commonly used active material for reference electrodes.Although lithium anodes are regarded as the holy grail of lithium batteries,decades of exploration have not led to the successful commercialization of LMBs,due mainly to the challenges related to the inherent properties of lithium metal.To pave the way for further investigation,herein,a comprehensive review focusing on the fundamental science of lithium are provided.Firstly,the natures of lithium atoms and their isotopes,lithium clusters and lithium crystals are revisited,especially their structural and energetic properties.Subsequently,the electrochemical properties of lithium metal are reviewed.Numerous important concepts and scientific questions,including the electronic structure of lithium,influence of high pressure and low temperature on the properties of lithium,factors influencing lithium deposition,generation of lithium dendrites,and electrode potential of lithium in different electrolytes,are explained and analyzed in detail.Approaches to improve the performance of lithium anodes and thoughtfulness about the electrode potential in lithium battery research are proposed.展开更多
The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its...The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.展开更多
The lithium dendrite and parasitic reactions are two major challenges for lithium(Li)metal anode—the most promising anode materials for high-energy-density batteries.In this work,both the dendrite and parasitic react...The lithium dendrite and parasitic reactions are two major challenges for lithium(Li)metal anode—the most promising anode materials for high-energy-density batteries.In this work,both the dendrite and parasitic reactions that occurred between the liquid electrolyte and Li-metal anode could be largely inhibited by regulating the Li+-solvation structure.The saturated Li+-solvation species exist in commonly used LiPF 6 liquid electrolyte that needs extra energy to desolvation during Li-electrodeposition.Partial solvation induced high-energy state Li-ions would be more energy favorable during the electron-reduction process,dominating the competition with solvent reduction reactions.The Li-symmetric cells that are cycling at higher temperatures show better performance;the cycled lithium metal anode with metallic lustre and the dendrite-free surface is observed.Theoretical calculation and experimental measurements reveal the existence of high-energy state Li+-solvates species,and their concentration increases with temperature.This study provides insight into the Li+-solvation structure and its electrodeposition characteristics.展开更多
During the last decade,the rapid development of lithium-ion battery(LIB)energy storage systems has provided significant support for the efficient operation of renewable energy stations.In the coming years,the service ...During the last decade,the rapid development of lithium-ion battery(LIB)energy storage systems has provided significant support for the efficient operation of renewable energy stations.In the coming years,the service life demand of energy storage systems will be further increased to 30 years from the current 20 years on the basis of the equivalent service life of renewable energy stations.However,the life of the present LIB is far from meeting such high demand.Therefore,research on the next-generation LIB with ultra-long service life is imminent.Prelithiation technology has been widely studied as an important means to compensate for the initial coulombic efficiency loss and improve the service life of LIBs.This review systematically summarized the different prelithiation methods from anode and cathode electrodes.Moreover,the large-scale industrialization challenge and the possibility of the existing prelithiation technology are analyzed,based on three key parameters:industry compatibility,prelithiation efficiency,and energy density.Finally,the future trends of improvement in LIB performance by other overlithiated cathode materials are presented,which gives a reference for subsequent research.展开更多
基金financial support from the National Natural Science Foundation of China(41902272)Gansu Province Basic Research Innovation Group Project(21JR7RA347).
文摘To ensure the long-term safety and stability of bridge pile foundations in permafrost regions,it is necessary to investigate the rheological effects on the pile tip and pile side bearing capacities.The creep characteristics of the pile-frozen soil interface are critical for determining the long-term stability of permafrost pile foundations.This study utilized a self-developed large stress-controlled shear apparatus to investigate the shear creep characteristics of the frozen silt-concrete interface,and examined the influence of freezing temperatures(−1,−2,and−5°C),contact surface roughness(0,0.60,0.75,and 1.15 mm),normal stress(50,100,and 150 kPa),and shear stress on the creep characteristics of the contact surface.By incorporating the contact surface’s creep behavior and development trends,we established a creep constitutive model for the frozen silt-concrete interface based on the Nishihara model,introducing nonlinear elements and a damage factor.The results revealed significant creep effects on the frozen silt-concrete interface under constant load,with creep displacement at approximately 2-15 times the instantaneous displacement and a failure creep displacement ranging from 6 to 8 mm.Under different experimental conditions,the creep characteristics of the frozen silt-concrete interface varied.A larger roughness,lower freezing temperatures,and higher normal stresses resulted in a longer sample attenuation creep time,a lower steady-state creep rate,higher long-term creep strength,and stronger creep stability.Building upon the Nishihara model,we considered the influence of shear stress and time on the viscoelastic viscosity coefficient and introduced a damage factor to the viscoplasticity.The improved model effectively described the entire creep process of the frozen silt-concrete interface.The results provide theoretical support for the interaction between pile and soil in permafrost regions.
基金gratitude to the National Natural Science Foundation of China(No.22279070,U21A20170,22279071 and 52206263)the Ministry of Science and Technology of China(No.2019YFA0705703 and 2019YFE0100200)The authors thank Joint Work Plan for Research Projects under the Clean Vehicles Consortium at U.S.and China-Clean Energy Research Center(CERCCVC2.0,2016-2020)。
文摘As a key material for lithium metal batteries(LMBs),lithium metal is one of the most promising anode materials to break the bottleneck of battery energy density and a commonly used active material for reference electrodes.Although lithium anodes are regarded as the holy grail of lithium batteries,decades of exploration have not led to the successful commercialization of LMBs,due mainly to the challenges related to the inherent properties of lithium metal.To pave the way for further investigation,herein,a comprehensive review focusing on the fundamental science of lithium are provided.Firstly,the natures of lithium atoms and their isotopes,lithium clusters and lithium crystals are revisited,especially their structural and energetic properties.Subsequently,the electrochemical properties of lithium metal are reviewed.Numerous important concepts and scientific questions,including the electronic structure of lithium,influence of high pressure and low temperature on the properties of lithium,factors influencing lithium deposition,generation of lithium dendrites,and electrode potential of lithium in different electrolytes,are explained and analyzed in detail.Approaches to improve the performance of lithium anodes and thoughtfulness about the electrode potential in lithium battery research are proposed.
基金supported by the National Natural Science Foundation of China(22322304,22273092,22373095)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0450101)+2 种基金the Innovation Program for Quantum Science and Technology(2021ZD0303306)the USTC Tang ScholarThe authors wish to acknowledge the Supercomputing Center of the USTC for providing computational resources.
文摘The achievement of electrical spin control is highly desirable.One promising strategy involves electrically mod-ulating the Rashba spin orbital coupling effect in materials.A semiconductor with high sensitivity in its Rashba constant to external electric fields holds great potential for short channel lengths in spin field-effect transistors,which is crucial for preserving spin coherence and enhancing integration density.Hence,two-dimensional(2D)Rashba semiconductors with large Rashba constants and significant electric field responses are highly desirable.Herein,by employing first-principles calculations,we design a thermodynamically stable 2D Rashba semiconductor,YSbTe_(3),which possesses an indirect band gap of 1.04 eV,a large Rashba constant of 1.54 eV·Åand a strong electric field response of up to 4.80 e·Å^(2).In particular,the Rashba constant dependence on the electric field shows an unusual nonlinear relationship.At the same time,YSbTe_(3)has been identified as a 2D ferroelectric material with a moderate polarization switching energy barrier(~0.33 eV per formula).By changing the electric polarization direction,the Rashba spin texture of YSbTe_(3)can be reversed.These out-standing properties make the ferroelectric Rashba semiconductor YSbTe_(3)quite promising for spintronic applications.
基金This work was funded by the National Natural Science Foundation of China (52073161 and U1564205)the Ministry of Science and Technology of China (No.2019YFE0100200 and 2019YFA0705703)+1 种基金The authors also thank Joint Work Plan for Research Projects under the Clean Vehicles Consortium at U.S.and China-Clean Energy Research Center (CERC-CVC2.0,2016-2020)thank Tsinghua University-Zhangjiagang Joint Institute for Hydrogen Energy and Lithium Ion Battery Technology.
文摘The lithium dendrite and parasitic reactions are two major challenges for lithium(Li)metal anode—the most promising anode materials for high-energy-density batteries.In this work,both the dendrite and parasitic reactions that occurred between the liquid electrolyte and Li-metal anode could be largely inhibited by regulating the Li+-solvation structure.The saturated Li+-solvation species exist in commonly used LiPF 6 liquid electrolyte that needs extra energy to desolvation during Li-electrodeposition.Partial solvation induced high-energy state Li-ions would be more energy favorable during the electron-reduction process,dominating the competition with solvent reduction reactions.The Li-symmetric cells that are cycling at higher temperatures show better performance;the cycled lithium metal anode with metallic lustre and the dendrite-free surface is observed.Theoretical calculation and experimental measurements reveal the existence of high-energy state Li+-solvates species,and their concentration increases with temperature.This study provides insight into the Li+-solvation structure and its electrodeposition characteristics.
基金funded by the National Natural Science Foundation of China(No.U21A20170(X.He))the Ministry of Science and Technology of China(No.2019YFE0100200(X.He)and 2019YFA0705703(L.Wang))the Tsinghua University Initiative Scientific Research Program(No.2019Z02UTY06(X.He)and 2019THFS0132(L.Wang)).The authors also thank Joint Work Plan for Research Projects under the Clean Vehicles Consortium at U.S.and China-Clean Energy Research Center(CERC-CVC2.0,2016-2020)
文摘During the last decade,the rapid development of lithium-ion battery(LIB)energy storage systems has provided significant support for the efficient operation of renewable energy stations.In the coming years,the service life demand of energy storage systems will be further increased to 30 years from the current 20 years on the basis of the equivalent service life of renewable energy stations.However,the life of the present LIB is far from meeting such high demand.Therefore,research on the next-generation LIB with ultra-long service life is imminent.Prelithiation technology has been widely studied as an important means to compensate for the initial coulombic efficiency loss and improve the service life of LIBs.This review systematically summarized the different prelithiation methods from anode and cathode electrodes.Moreover,the large-scale industrialization challenge and the possibility of the existing prelithiation technology are analyzed,based on three key parameters:industry compatibility,prelithiation efficiency,and energy density.Finally,the future trends of improvement in LIB performance by other overlithiated cathode materials are presented,which gives a reference for subsequent research.
