In this work,a flake-structured Co2B2O5 material was obtained by a simple sol-gel method and researched for use in sodium ion batteries firstly.When serving as anode material for sodium ion batteries,it exhibits the h...In this work,a flake-structured Co2B2O5 material was obtained by a simple sol-gel method and researched for use in sodium ion batteries firstly.When serving as anode material for sodium ion batteries,it exhibits the high initial reversible capacity of 466 mAh·g-1 at a current density of 100 mA·g-1.Through the recombination of carbon nanotubes(CNTs),the composite Co2B2O5/CNTs delivers the initial reversible capacity of 464 mAh·g-1,and324 mAh·g-1 is obtained after 60 cycles under the current density of 100 mA·g-1.When under the current density of 1000 mA·g-1,a capacity of 236 mAh·g-1 is obtained for Co2B2O5/CNTs while 160 mAh·g-1 for Co2B2O5.Moreover,the sodium storage behavior of Co2B2O5 is identified by kinetic analysis.The higher Na+capacitive contribution of Co2B2O5/CNTs could account for the enhanced rate performance.The results indicate that Co2B2O5 is a promising anode material for sodium ion batteries.展开更多
Based on density functional theory and generalized gradient approximation calculations, the adsorption of Co2B2 and Ni2B2 clusters on the rutile TiO2 （110） surface has been investigated utilizing periodic supercell ...Based on density functional theory and generalized gradient approximation calculations, the adsorption of Co2B2 and Ni2B2 clusters on the rutile TiO2 （110） surface has been investigated utilizing periodic supercell models. Unambiguously, the results demonstrate that the hollow site turns out to be preferable for Co2B2 cluster while Ti2 site is for Ni2B2 cluster to adsorb. Orbital population analysis indicates a strong interaction between Co2B2 and O atom of TiO2 surface, which can be attributed to the overlap of Co 3d and surface O 2p orbital. Similarly, for Ni2B2 , the bonding interaction occurs mostly through the interaction of Ni 3d/4s and O 2p orbitals. Note that, there is also an interaction within the Co2B2 clusters （Ni2B2） through B 2s/2p and Co 3d orbitals （Ni 3d/4s）. Moreover, orbital analysis results shows that the strong bonding between Ni2B2 and Ti2 site is due to the overlap of HOMO of Ni2B2 and d-orbital of five-coordinated titanium atoms.展开更多
A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 ...A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 （Global Ocean-Atmosphere-Land system coupled model）, developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP）, Chinese Academy of Sciences （CAS）. In order to validate the model, the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980s for the globe and Northern Hemisphere, and better the important cold （1950 1976） and warm （1977-2000） periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations （significant at a more than 0.05 confidence level）. The range of winter temperature departures for North China is between those for the eastern and western China＇s Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario. The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5~C relative to climate mean （1960-1990）. Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.展开更多
基金financially supported by the National Natural Science Foundation of China(No.21673136)the Science and Technology Commission of Shanghai Municipality(No.19DZ2271100)。
文摘In this work,a flake-structured Co2B2O5 material was obtained by a simple sol-gel method and researched for use in sodium ion batteries firstly.When serving as anode material for sodium ion batteries,it exhibits the high initial reversible capacity of 466 mAh·g-1 at a current density of 100 mA·g-1.Through the recombination of carbon nanotubes(CNTs),the composite Co2B2O5/CNTs delivers the initial reversible capacity of 464 mAh·g-1,and324 mAh·g-1 is obtained after 60 cycles under the current density of 100 mA·g-1.When under the current density of 1000 mA·g-1,a capacity of 236 mAh·g-1 is obtained for Co2B2O5/CNTs while 160 mAh·g-1 for Co2B2O5.Moreover,the sodium storage behavior of Co2B2O5 is identified by kinetic analysis.The higher Na+capacitive contribution of Co2B2O5/CNTs could account for the enhanced rate performance.The results indicate that Co2B2O5 is a promising anode material for sodium ion batteries.
基金supported by the Foundation of State Key Laboratory of Coal Combustion of Huazhong University of Science and Technology (FSKLCC1110)the Natural Science Foundation of Fujian Province (2012J01032, 2012J01041)
文摘Based on density functional theory and generalized gradient approximation calculations, the adsorption of Co2B2 and Ni2B2 clusters on the rutile TiO2 （110） surface has been investigated utilizing periodic supercell models. Unambiguously, the results demonstrate that the hollow site turns out to be preferable for Co2B2 cluster while Ti2 site is for Ni2B2 cluster to adsorb. Orbital population analysis indicates a strong interaction between Co2B2 and O atom of TiO2 surface, which can be attributed to the overlap of Co 3d and surface O 2p orbital. Similarly, for Ni2B2 , the bonding interaction occurs mostly through the interaction of Ni 3d/4s and O 2p orbitals. Note that, there is also an interaction within the Co2B2 clusters （Ni2B2） through B 2s/2p and Co 3d orbitals （Ni 3d/4s）. Moreover, orbital analysis results shows that the strong bonding between Ni2B2 and Ti2 site is due to the overlap of HOMO of Ni2B2 and d-orbital of five-coordinated titanium atoms.
基金the National Natural Science Foundation of China under Grant No.40675038,National Basic Research Program of China(973 Program-2006CB403404)the Chinese Academy of Sciences innovative team of international cooperation partnership projects(the project of climate system model development and application studies).
文摘A simulation of climate change trends over North China in the past 50 years and future 30 years was performed with the actual greenhouse gas concentration and IPCC SRES B2 scenario concentration by IAP/LASG GOALS 4.0 （Global Ocean-Atmosphere-Land system coupled model）, developed by the State Key Laboratory of Numerical Modelling for Atmospheric Sciences and Geophysical Fluid Dynamics （LASG）, Institute of Atmospheric Physics （IAP）, Chinese Academy of Sciences （CAS）. In order to validate the model, the modern climate during 1951-2000 was first simulated by the GOALS model with the actual greenhouse gas concentration, and the simulation results were compared with observed data. The simulation results basically reproduce the lower temperature from the 1960s to mid-1970s and the warming from the 1980s for the globe and Northern Hemisphere, and better the important cold （1950 1976） and warm （1977-2000） periods in the past 50 years over North China. The correlation coefficient is 0.34 between simulations and observations （significant at a more than 0.05 confidence level）. The range of winter temperature departures for North China is between those for the eastern and western China＇s Mainland. Meanwhile, the summer precipitation trend turning around the 1980s is also successfully simulated. The climate change trends in the future 30 years were simulated with the CO2 concentration under IPCC SRES-B2 emission scenario. The results show that, in the future 30 years, winter temperature will keep a warming trend in North China and increase by about 2.5~C relative to climate mean （1960-1990）. Meanwhile, summer precipitation will obviously increase in North China and decrease in South China, displaying a south-deficit-north-excessive pattern of precipitation.
