As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the...As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the specific capacities,intrinsic drawbacks such as poor initial Coulombic efficiency and low volumetric capacity could not be avoided.Herein,we propose a strategy to prepare carbon supported MoO_(2)spheres used for lithium-ion battery with high volumetric capacity density.A high initial Coulombic efficiency of 76.5%is obtained due to limited solid electrolyte interface film formed on the exposed surface.Meantime,the sample with an optimal carbon content and a proper structural strength reveals a higher reversible capacity of 956 mA h g^(-1)than the theoretical capacity of crystalline Mo O_(2)(838 mA h g^(-1))and a high capacity retention ratio of 96.4%after 100 cycles at 0.5 A g^(-1).And an effective compaction capacity density(under 5 MPa)of 670 mA h cm^(-3)of the spheres proves its potential value in practical applications.展开更多
Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission elec...Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission electron microscopy(HRTEM), scanning electron microscopy(SEM), atomic force microscopy(AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_(0.82)Ga_(0.18)As/InP heterostructure, the In_xGa_(1-x)As buffer layer was grown. The residual strain of the In_(0.82)Ga_(0.18)As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium(In) content In_(0.82)Ga_(0.18)As epitaxial layer has significant influence on the carrier concentration.展开更多
基金financially supported by the National Natural Science Foundation of China(21975250)the National Key R&D Program of China(2017YFE0198100)+1 种基金the Hightech Research Key laboratory of Zhenjiang(SS2018002)Jiangsu Post-doctoral Research Funding Program(2020Z257)。
文摘As important ingredients in lithium-ion battery,the Coulombic efficiency and power density greatly impact the electrochemical performances.Although recent literatures have reported nano-porous materials to enhance the specific capacities,intrinsic drawbacks such as poor initial Coulombic efficiency and low volumetric capacity could not be avoided.Herein,we propose a strategy to prepare carbon supported MoO_(2)spheres used for lithium-ion battery with high volumetric capacity density.A high initial Coulombic efficiency of 76.5%is obtained due to limited solid electrolyte interface film formed on the exposed surface.Meantime,the sample with an optimal carbon content and a proper structural strength reveals a higher reversible capacity of 956 mA h g^(-1)than the theoretical capacity of crystalline Mo O_(2)(838 mA h g^(-1))and a high capacity retention ratio of 96.4%after 100 cycles at 0.5 A g^(-1).And an effective compaction capacity density(under 5 MPa)of 670 mA h cm^(-3)of the spheres proves its potential value in practical applications.
基金supported by the National Key Basic Research Program of China(No.2012CB619200)the National Natural Science Foundation of China(No.61474053)+1 种基金the State Key Laboratory for Mechanical Behavior of Materials of Xi'an Jiaotong University(No.20161806)the Natural Science Basic Research Open Foundation of the Key Lab of Automobile Materials,Ministry of Education,Jilin University(No.1018320144001)
文摘Microstructure and misfit dislocation behavior in In_xGa_(1-x)As/InP heteroepitaxial materials grown by low pressure metal organic chemical vapor deposition(LP-MOCVD) were analyzed by high resolution transmission electron microscopy(HRTEM), scanning electron microscopy(SEM), atomic force microscopy(AFM), Raman spectroscopy and Hall effect measurements. To optimize the structure of In_(0.82)Ga_(0.18)As/InP heterostructure, the In_xGa_(1-x)As buffer layer was grown. The residual strain of the In_(0.82)Ga_(0.18)As epitaxial layer was calculated. Further, the periodic growth pattern of the misfit dislocation at the interface was discovered and verified. Then the effects of misfit dislocation on the surface morphology and microstructure of the material were studied. It is found that the misfit dislocation of high indium(In) content In_(0.82)Ga_(0.18)As epitaxial layer has significant influence on the carrier concentration.