The nanocomposite films were prepared by direct intercalation of poly(ethylene oxide) and PEO into MoO 3 xerogel via sol-gel route.The electrochromic behavior and the chemical conditions of Li + ions were investigat...The nanocomposite films were prepared by direct intercalation of poly(ethylene oxide) and PEO into MoO 3 xerogel via sol-gel route.The electrochromic behavior and the chemical conditions of Li + ions were investigated by cyclic voltammograms,UV-visible spectral transmittance and XPS.The results show that the cycling efficiency and the reversibility of insertion/extraction of Li + ions in (PEO) 1MoO 3·nH 2O nanocomposite film were improved.The intercalation of PEO into MoO 3 xerogel modulated the wavelength range of electrochromism and enhanced the electrochromic efficiency.Two different chemical conditions of Li + ions existing in the interlayer and interstitial positions of MoO 3 lattice were observed in MoO 3 xerogel and (PEO) 1MoO 3·nH 2O nanocomposite films.展开更多
TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and 2-MnO2 type TiO2 were investigated by density functional theory （DFT）. The key issues are focused o...TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and 2-MnO2 type TiO2 were investigated by density functional theory （DFT）. The key issues are focused on the lithium insertion sites, electronic structures, and the conducting paths of Li＋ ions. Our calculated data indicate the calculated voltage of 2-MnO2 type TiO2 is higher than that of lepidocrocite type TiO2. The Li＋ ion migration energy barrier of lepidocroeite type YiO2 along the [1 0 0] direction （0.45 eV） is lower than that of along the [110] direction （0.57 eV）. The energy barriers of 2-MnO2 type TiO2 to move a Li＋ ion among the adjacent embedded sites （16c or 8a sites） is 0.68 eV.展开更多
Superlattice structures resulting from vacancy ordering have been observed in many materials.Here we report vacancy ordering behavior inⅢ_(2)Ⅵ_(3)nanowires.The formation of layer-like structural vacancies has been a...Superlattice structures resulting from vacancy ordering have been observed in many materials.Here we report vacancy ordering behavior inⅢ_(2)Ⅵ_(3)nanowires.The formation of layer-like structural vacancies has been achieved during the synthesis of In_(2)Se_(3)nanowires through a vapor-transport route.Doping In_(2)Se_(3)nanowires with small amounts of Ga during synthesis can completely change the structural vacancy ordering from a layer-like to a screw-like pattern for(In_(x)Ga_(1-x))_(2)Se_(3)nanowires.Lithium atoms can fill in the layer-like structural vacancies of In_(2)Se_(3)nanowires and generate new types of vacancy and lithium atom ordering superlattices.The screw-patterned vacancies of(In_(x)Ga_(1-x))_(2)Se_(3)nanowires show reversible lithium insertion.Our results contribute to the understanding of structure property correlations ofⅢ_(2)Ⅵ_(3)materials used in lithium ion storage,photovoltaics,and phase change memory.展开更多
Cucurbit[6]uril(CB[6])and its complex with VO^(2+)(CB[6]VO)were intercalated into lamellar vanadium pentoxide in several proportions,generating a series of hybrid pillarised intercalates in the form of xerogel films.T...Cucurbit[6]uril(CB[6])and its complex with VO^(2+)(CB[6]VO)were intercalated into lamellar vanadium pentoxide in several proportions,generating a series of hybrid pillarised intercalates in the form of xerogel films.These different vips dramatically affect Li^(+)insertion/expulsion from the composites during redox processes.Our results show that CB[6]has little effect or may even impair charge compensation by Li^(+),while CB[6]VO exerts the opposite effect,enhancing this process when compared to pure vanadium pentoxide.This is clear evidence that CB[6]binds these ions retaining them in the bulk structure,and when the oculi are blocked by VO^(2+)ions,the macrocycle acts as a non-coordinating pillar in the structure favoring ion traffic,and charge compensation processes become easier.Specific charge capacities for pure vanadium pentoxide,CB[6]and CB[6]VO intercalates correspond to 158,168 and 230 mA h g^(-1)respectively.展开更多
文摘The nanocomposite films were prepared by direct intercalation of poly(ethylene oxide) and PEO into MoO 3 xerogel via sol-gel route.The electrochromic behavior and the chemical conditions of Li + ions were investigated by cyclic voltammograms,UV-visible spectral transmittance and XPS.The results show that the cycling efficiency and the reversibility of insertion/extraction of Li + ions in (PEO) 1MoO 3·nH 2O nanocomposite film were improved.The intercalation of PEO into MoO 3 xerogel modulated the wavelength range of electrochromism and enhanced the electrochromic efficiency.Two different chemical conditions of Li + ions existing in the interlayer and interstitial positions of MoO 3 lattice were observed in MoO 3 xerogel and (PEO) 1MoO 3·nH 2O nanocomposite films.
基金Acknowledgement This work was financially supported by the Major Program of the Natural Science Foundation of China （Grant No. 51090380）, the National Science Foundation for Distinguished Young Scholars of China （Grant No. 51125018）, the Knowledge Innovation Program of the Chinese Academy of Sciences （KGCX2-YW-214） and the special funds of ＂Mountain Tai Scholar＂ construction project. The computing platform was supported by the Computer Facility for Theoretical and Computational Chemistry, Institute of Chemistry （CFCC）, Chinese Academy of Sciences （CAS）.
文摘TiO2 is a latent anode material for rechargeable lithium batteries. Our simulation models, basing lepidocrocite and 2-MnO2 type TiO2 were investigated by density functional theory （DFT）. The key issues are focused on the lithium insertion sites, electronic structures, and the conducting paths of Li＋ ions. Our calculated data indicate the calculated voltage of 2-MnO2 type TiO2 is higher than that of lepidocrocite type TiO2. The Li＋ ion migration energy barrier of lepidocroeite type YiO2 along the [1 0 0] direction （0.45 eV） is lower than that of along the [110] direction （0.57 eV）. The energy barriers of 2-MnO2 type TiO2 to move a Li＋ ion among the adjacent embedded sites （16c or 8a sites） is 0.68 eV.
基金Y.C.acknowledges support from U.S.Department of Energy under the Award Number DE-FG36-08GOI8004.
文摘Superlattice structures resulting from vacancy ordering have been observed in many materials.Here we report vacancy ordering behavior inⅢ_(2)Ⅵ_(3)nanowires.The formation of layer-like structural vacancies has been achieved during the synthesis of In_(2)Se_(3)nanowires through a vapor-transport route.Doping In_(2)Se_(3)nanowires with small amounts of Ga during synthesis can completely change the structural vacancy ordering from a layer-like to a screw-like pattern for(In_(x)Ga_(1-x))_(2)Se_(3)nanowires.Lithium atoms can fill in the layer-like structural vacancies of In_(2)Se_(3)nanowires and generate new types of vacancy and lithium atom ordering superlattices.The screw-patterned vacancies of(In_(x)Ga_(1-x))_(2)Se_(3)nanowires show reversible lithium insertion.Our results contribute to the understanding of structure property correlations ofⅢ_(2)Ⅵ_(3)materials used in lithium ion storage,photovoltaics,and phase change memory.
文摘Cucurbit[6]uril(CB[6])and its complex with VO^(2+)(CB[6]VO)were intercalated into lamellar vanadium pentoxide in several proportions,generating a series of hybrid pillarised intercalates in the form of xerogel films.These different vips dramatically affect Li^(+)insertion/expulsion from the composites during redox processes.Our results show that CB[6]has little effect or may even impair charge compensation by Li^(+),while CB[6]VO exerts the opposite effect,enhancing this process when compared to pure vanadium pentoxide.This is clear evidence that CB[6]binds these ions retaining them in the bulk structure,and when the oculi are blocked by VO^(2+)ions,the macrocycle acts as a non-coordinating pillar in the structure favoring ion traffic,and charge compensation processes become easier.Specific charge capacities for pure vanadium pentoxide,CB[6]and CB[6]VO intercalates correspond to 158,168 and 230 mA h g^(-1)respectively.
