Li metal is considered one of the most promising candidates for the anode material in high-energy-density Li-ion batteries. However, the dendritic growth of Li metal during the plating/stripping process can severely r...Li metal is considered one of the most promising candidates for the anode material in high-energy-density Li-ion batteries. However, the dendritic growth of Li metal during the plating/stripping process can severely reduce Coulombic efficiency and cause safety problems, which is a key issue limiting the application of Li metal anodes. Herein, we present a novel strategy for dendrite-free deposition of Li by modifying the Cu current collector with a three-dimensional carbon nanofiber （CNF） network. Owing to the large surface area and high conductivity of the CNF network, Li metal is inserted into and deposited onto the CNF directly, and no dendritic Li metal is observed, leaving a flat Li metal surface. With Li metal as the counter electrode for Li deposition, an average Coulombic efficiency of 99.9% was achieved for more than 300 cycles, at large current densities of 1.0 and 2.0 mA·cm^-2, and with a high Li loading of 1 mAh·cm^-2. The scalability of the preparation method and the impressive results achieved here demonstrate the potential for the application of our design to the future development of dendrite-free Li metal anodes.展开更多
The chemical vapor deposition （CVD） of graphene on Cu substrates enables the fabrication of large-area monolayer graphene on desired substrates. However, during the transfer of the synthesized graphene, topographic ...The chemical vapor deposition （CVD） of graphene on Cu substrates enables the fabrication of large-area monolayer graphene on desired substrates. However, during the transfer of the synthesized graphene, topographic defects are unavoidably formed along the Cu grain boundaries, degrading the electrical properties of graphene and increasing the device-to-device variability. Here, we introduce a method of hot-pressing as a surface pre-treatment to improve the thermal stability of Cu thin film for the suppression of grain boundary grooving. The flattened Cu thin film maintains its smooth surface even after the subsequent high temperature CVD process necessary for graphene growth, and the formation of graphene without wrinkles is realized. Graphene field effect transistors （FETs） fabricated using the graphene synthesized on hot-pressed Cu thin film exhibit superior field effect mobility and significantly reduced device-to-device variation.展开更多
文摘Li metal is considered one of the most promising candidates for the anode material in high-energy-density Li-ion batteries. However, the dendritic growth of Li metal during the plating/stripping process can severely reduce Coulombic efficiency and cause safety problems, which is a key issue limiting the application of Li metal anodes. Herein, we present a novel strategy for dendrite-free deposition of Li by modifying the Cu current collector with a three-dimensional carbon nanofiber （CNF） network. Owing to the large surface area and high conductivity of the CNF network, Li metal is inserted into and deposited onto the CNF directly, and no dendritic Li metal is observed, leaving a flat Li metal surface. With Li metal as the counter electrode for Li deposition, an average Coulombic efficiency of 99.9% was achieved for more than 300 cycles, at large current densities of 1.0 and 2.0 mA·cm^-2, and with a high Li loading of 1 mAh·cm^-2. The scalability of the preparation method and the impressive results achieved here demonstrate the potential for the application of our design to the future development of dendrite-free Li metal anodes.
文摘The chemical vapor deposition （CVD） of graphene on Cu substrates enables the fabrication of large-area monolayer graphene on desired substrates. However, during the transfer of the synthesized graphene, topographic defects are unavoidably formed along the Cu grain boundaries, degrading the electrical properties of graphene and increasing the device-to-device variability. Here, we introduce a method of hot-pressing as a surface pre-treatment to improve the thermal stability of Cu thin film for the suppression of grain boundary grooving. The flattened Cu thin film maintains its smooth surface even after the subsequent high temperature CVD process necessary for graphene growth, and the formation of graphene without wrinkles is realized. Graphene field effect transistors （FETs） fabricated using the graphene synthesized on hot-pressed Cu thin film exhibit superior field effect mobility and significantly reduced device-to-device variation.
