A novel lightweight three-dimensional （3D） composite anode for a fast-charging] discharging Li-ion battery （LIB） was fabricated entirely using one-dimensional （1D） nanomaterials, i.e., Cu nanowires （CuNWs） and...A novel lightweight three-dimensional （3D） composite anode for a fast-charging] discharging Li-ion battery （LIB） was fabricated entirely using one-dimensional （1D） nanomaterials, i.e., Cu nanowires （CuNWs） and multi-walled C nanotubes （MWCNTs）. Because of the excellent electrical conductivity, high-aspect ratio structures, and large surface areas of these nanomaterials, the CuNW-MWCNT composite （CNMC） with 3D structure provides significant advantages regarding the transport pathways for both electrons and ions. As an advanced binder-free anode, a CuNW-MWCNT composite film with a controllable thickness （~ 600 prn） exhibited a considerably low sheet resistance, and internal cell resistance. Furthermore, the random CuNW network with 3D structure acting as a rigid framework not only prevented MWCNT shrinkage and expansion due to aggregation and swelling but also minimized the effect of the volume change during the charge/discharge process. Both a half cell and a full cell of LIBs with the CNMC anode exhibited high specific capacities and Coulombic efficiendes, even at a high current. More importantly, we for the first time overcame the limitation of MWCNTs as anode materials for fast-charging]discharging LIBs （both half cells and full cells） by employing CuNWs, and the resulting anode can be applied to flexible LIBs. This innovative anode structure can lead to the development of ultrafast chargeable LIBs for electric vehides.展开更多
Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l＋l- γ,（l=e,μ） in the Standard Model, including two kinds of contributions from the magnetic-penguin opera...Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l＋l- γ,（l=e,μ） in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l＋l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future.展开更多
文摘A novel lightweight three-dimensional （3D） composite anode for a fast-charging] discharging Li-ion battery （LIB） was fabricated entirely using one-dimensional （1D） nanomaterials, i.e., Cu nanowires （CuNWs） and multi-walled C nanotubes （MWCNTs）. Because of the excellent electrical conductivity, high-aspect ratio structures, and large surface areas of these nanomaterials, the CuNW-MWCNT composite （CNMC） with 3D structure provides significant advantages regarding the transport pathways for both electrons and ions. As an advanced binder-free anode, a CuNW-MWCNT composite film with a controllable thickness （~ 600 prn） exhibited a considerably low sheet resistance, and internal cell resistance. Furthermore, the random CuNW network with 3D structure acting as a rigid framework not only prevented MWCNT shrinkage and expansion due to aggregation and swelling but also minimized the effect of the volume change during the charge/discharge process. Both a half cell and a full cell of LIBs with the CNMC anode exhibited high specific capacities and Coulombic efficiendes, even at a high current. More importantly, we for the first time overcame the limitation of MWCNTs as anode materials for fast-charging]discharging LIBs （both half cells and full cells） by employing CuNWs, and the resulting anode can be applied to flexible LIBs. This innovative anode structure can lead to the development of ultrafast chargeable LIBs for electric vehides.
基金Supported by National Natural Science Foundation of China(11005006,11172008)Ri Xin Foundation of BJUT
文摘Using the Bs meson wave function extracted from non-leptonic Bs decays, we reevaluate the rare decays Bs→l＋l- γ,（l=e,μ） in the Standard Model, including two kinds of contributions from the magnetic-penguin operator with virtual and real photons. We find that contributions to the exclusive decays from the magnetic-penguin operator b→sγ with real photons, which were regarded as negligible in the previous literature, are large and the branching ratios Bs→l＋l-γ are enhanced by a factor of almost 2. With the predicted branching ratios of the order of 10-8, it is expected that these radiative dileptonic decays will be detected in LHC-b and B factories in the near future.
