The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub...The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub> and H<sub>2</sub>. The gas-phase SiCl<sub>4</sub> was injected with H<sub>2</sub> gas into the microwave plasma torch generated by N<sub>2</sub> and air swirl gas, and then the dark brown powders were deposited on the inner wall of a quartz tube. The sample was analyzed by an X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The average size and oxidation x values of synthesized SiO<sub>x</sub>-NPs were approximately 230 nm and 0.91, respectively. Furthermore, the volumetric charge capacity is 1127 mAh/g and has 89.2% retention after 100 cycles.展开更多
Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phe...Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phenomenon are unclear.For the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode material.Herein,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1<X<2)→MnO→Mn metal,followed by a reversible reaction between Mn metal and Mn3O4.Furthermore,soft X-ray absorption spectroscopy results indicate that additional reversible formation-decomposition of the electrolyte-derived surface layer occurs and contributes to the reversible capacity of MnO2 after the first discharge.These findings contribute to further understanding of the reaction mechanism and additional lithium storage of MnO2 and suggest practical strategies for developing high energy density anode materials for next-generation Li batteries.展开更多
文摘The silicon oxide nano-powders (SiO<sub>x</sub>-NPs) were obtained in an atmospheric microwave plasma torch using a gas-phase silicon tetrachloride (SiCl<sub>4</sub>) with N<sub>2</sub> and H<sub>2</sub>. The gas-phase SiCl<sub>4</sub> was injected with H<sub>2</sub> gas into the microwave plasma torch generated by N<sub>2</sub> and air swirl gas, and then the dark brown powders were deposited on the inner wall of a quartz tube. The sample was analyzed by an X-ray photoelectron spectroscopy (XPS), a scanning electron microscope (SEM), an energy dispersive spectrometer (EDS), and an X-ray diffraction (XRD). The average size and oxidation x values of synthesized SiO<sub>x</sub>-NPs were approximately 230 nm and 0.91, respectively. Furthermore, the volumetric charge capacity is 1127 mAh/g and has 89.2% retention after 100 cycles.
基金supported by the Samsung Reserach Funding & Incubation Center of Samsung Electronics under Project Number MA1401-52。
文摘Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phenomenon are unclear.For the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode material.Herein,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1<X<2)→MnO→Mn metal,followed by a reversible reaction between Mn metal and Mn3O4.Furthermore,soft X-ray absorption spectroscopy results indicate that additional reversible formation-decomposition of the electrolyte-derived surface layer occurs and contributes to the reversible capacity of MnO2 after the first discharge.These findings contribute to further understanding of the reaction mechanism and additional lithium storage of MnO2 and suggest practical strategies for developing high energy density anode materials for next-generation Li batteries.
