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Vanadyl ethylene glycolate hollow hierarchical nanospheres were synthesized via a template-free polyol-induced solvothermal process. After sintering, vanadium pentoxide (V2O5) with well-preserved spherical structures was obtained. Refined X-ray diffraction and transmission electron microscopy analyses identified that the V2O5 hollow nanospheres were constructed from hierarchical nanocrystals with predominantly exposed {110} crystal planes. When applied as cathode materials for sodium-ion batteries (Na-ion batteries), the V2O5 hollow nanospheres delivered a specific discharge capacity of [similar]150 mA h g−1, which is equal to one Na+ ion insertion per V2O5 formula unit. Theoretical modelling on the volume expansion and stress evolution on Na+ ion insertion revealed that the prolonged cycling stability could be ascribed to the porous hollow spherical architecture. Furthermore, the exposed {110} facets of V2O5 nanocrystals with two-dimensional diffusion paths for Na+ ion intercalation also contribute to high rate capacity and excellent cycling performance.

Vanadyl ethylene glycolate hollow hierarchical nanospheres were synthesized via a template-free polyol-induced solvothermal process. After sintering, vanadium pentoxide (V2O5) with well-preserved spherical structures was obtained. Refined X-ray diffraction and transmission electron microscopy analyses identified that the V2O5 hollow nanospheres were constructed from hierarchical nanocrystals with predominantly exposed {110} crystal planes. When applied as cathode materials for sodium-ion batteries (Na-ion batteries), the V2O5 hollow nanospheres delivered a specific discharge capacity of [similar]150 mA h g−1, which is equal to one Na+ ion insertion per V2O5 formula unit. Theoretical modelling on the volume expansion and stress evolution on Na+ ion insertion revealed that the prolonged cycling stability could be ascribed to the porous hollow spherical architecture. Furthermore, the exposed {110} facets of V2O5 nanocrystals with two-dimensional diffusion paths for Na+ ion intercalation also contribute to high rate capacity and excellent cycling performance.

Vanadyl ethylene glycolate hollow hierarchical nanospheres were synthesized via a template-free polyol-induced solvothermal process. After sintering, vanadium pentoxide (V2O5) with well-preserved spherical structures was obtained. Refined X-ray diffraction and transmission electron microscopy analyses identified that the V2O5 hollow nanospheres were constructed from hierarchical nanocrystals with predominantly exposed {110} crystal planes. When applied as cathode materials for sodium-ion batteries (Na-ion batteries), the V2O5 hollow nanospheres delivered a specific discharge capacity of [similar]150 mA h g−1, which is equal to one Na+ ion insertion per V2O5 formula unit. Theoretical modelling on the volume expansion and stress evolution on Na+ ion insertion revealed that the prolonged cycling stability could be ascribed to the porous hollow spherical architecture. Furthermore, the exposed {110} facets of V2O5 nanocrystals with two-dimensional diffusion paths for Na+ ion intercalation also contribute to high rate capacity and excellent cycling performance.

Vanadyl ethylene glycolate hollow hierarchical nanospheres were synthesized via a template-free polyol-induced solvothermal process. After sintering, vanadium pentoxide (V2O5) with well-preserved spherical structures was obtained. Refined X-ray diffraction and transmission electron microscopy analyses identified that the V2O5 hollow nanospheres were constructed from hierarchical nanocrystals with predominantly exposed {110} crystal planes. When applied as cathode materials for sodium-ion batteries (Na-ion batteries), the V2O5 hollow nanospheres delivered a specific discharge capacity of [similar]150 mA h g−1, which is equal to one Na+ ion insertion per V2O5 formula unit. Theoretical modelling on the volume expansion and stress evolution on Na+ ion insertion revealed that the prolonged cycling stability could be ascribed to the porous hollow spherical architecture. Furthermore, the exposed {110} facets of V2O5 nanocrystals with two-dimensional diffusion paths for Na+ ion intercalation also contribute to high rate capacity and excellent cycling performance.

Nanosize molybdenum trisulfide, MoS3, was synthesized in a polyoxyethylene(2) nonylphenyl ether/cyclohexane/water microemulsion by acidifying ammonium tetrathiomolybdate solubilized in the water cores of inverse micelles. MoS3 was also prepared by thermal decomposition for comparison. X-ray diffraction, TEM, and electrochemical testing characterized the molybdenum trisulfide. By comparing the cyclic voltammetry results on MoS3 and S electrodes in lithium cells, the conclusions about the structure of MoS3 from previous research work have been confirmed. That is, the molybdenum trisulfide molecules were not a mixture of MoS2 and elemental S. Molybdenum trisulfide exists as Mo3S9 clusters, which are, in turn, linked by bridging SS bonds.

Ptx-WO3/C electrocatalysts were prepared by microwave colloid-reduction method. Transmission electron microscopy examination showed uniform dispersion of platinum with particle sizes less than 5 nm. Structures of the Ptx-WO3/C electrocatalysts were characterized by X-ray diffraction and energy dispersive spectroscopy, the electrochemical characteristics and electro-oxidation of electro-oxidation of ethanol on the Ptx-WO3/C electrocatalysts were also studied by cyclic voltammetry, linear sweep, and chronoamperometry. The results show that the Ptx-WO3/C electrocatalysts have higher catalytic activity to ethanol electrooxidation than the commercial Pt/C catalysts; perhaps caused by the “hydrogen spill-over effect.” The reaction mechanisms of the ethanol electro-oxidation on the Ptx-WO3/C were inferred according to the electrochemical characteristics and the data in the reported literature.

Nanocrystalline LiFePO4 and doped LiTi0.01Fe0.99PO4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K -edge X-ray absorption near-edge structure (XANES) measurements show that Ti4+ doping induces an increased unoccupied d-state in LiFePO4, resulting in an enhanced p-type semiconductivity. In situ Fe K -edge XANES measurements of Ti-doped and undoped LiFePO4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both LiFePO4 and doped LiTi0.01Fe0.99PO4 cathodes demonstrate good electrochemical performance.

Ptx-WO3/C electrocatalysts were prepared by microwave colloid-reduction method. Transmission electron microscopy examination showed uniform dispersion of platinum with particle sizes less than 5 nm. Structures of the Ptx-WO3/C electrocatalysts were characterized by X-ray diffraction and energy dispersive spectroscopy, the electrochemical characteristics and electro-oxidation of electro-oxidation of ethanol on the Ptx-WO3/C electrocatalysts were also studied by cyclic voltammetry, linear sweep, and chronoamperometry. The results show that the Ptx-WO3/C electrocatalysts have higher catalytic activity to ethanol electrooxidation than the commercial Pt/C catalysts; perhaps caused by the “hydrogen spill-over effect.” The reaction mechanisms of the ethanol electro-oxidation on the Ptx-WO3/C were inferred according to the electrochemical characteristics and the data in the reported literature.

Co3O4–C composite powder has been synthesized via spray pyrolysis of cobalt nitrate-sugar solution at 600°C and assessed for application as anode materials in Li-ion batteries. Microstructural characterization by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirm an even distribution of carbon throughout particles, as well as the presence of a carbon-based surface sheath surrounding Co3O4–C particle agglomerates. Charge-discharge cycling of half-cells indicates a stable reversible discharge capacity above 800 mAh g−1. Equivalent circuit modeling of Nyquist plots show the Co3O4–C electrode has significant kinetic advantages over non-composite transition metal oxide electrodes.

Ptx-WO3/C electrocatalysts were prepared by microwave colloid-reduction method. Transmission electron microscopy examination showed uniform dispersion of platinum with particle sizes less than 5 nm. Structures of the Ptx-WO3/C electrocatalysts were characterized by X-ray diffraction and energy dispersive spectroscopy, the electrochemical characteristics and electro-oxidation of electro-oxidation of ethanol on the Ptx-WO3/C electrocatalysts were also studied by cyclic voltammetry, linear sweep, and chronoamperometry. The results show that the Ptx-WO3/C electrocatalysts have higher catalytic activity to ethanol electrooxidation than the commercial Pt/C catalysts; perhaps caused by the “hydrogen spill-over effect.” The reaction mechanisms of the ethanol electro-oxidation on the Ptx-WO3/C were inferred according to the electrochemical characteristics and the data in the reported literature.

Nanocrystalline LiFePO4 and doped LiTi0.01Fe0.99PO4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K -edge X-ray absorption near-edge structure (XANES) measurements show that Ti4+ doping induces an increased unoccupied d-state in LiFePO4, resulting in an enhanced p-type semiconductivity. In situ Fe K -edge XANES measurements of Ti-doped and undoped LiFePO4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both LiFePO4 and doped LiTi0.01Fe0.99PO4 cathodes demonstrate good electrochemical performance.

Ptx-WO3/C electrocatalysts were prepared by microwave colloid-reduction method. Transmission electron microscopy examination showed uniform dispersion of platinum with particle sizes less than 5 nm. Structures of the Ptx-WO3/C electrocatalysts were characterized by X-ray diffraction and energy dispersive spectroscopy, the electrochemical characteristics and electro-oxidation of electro-oxidation of ethanol on the Ptx-WO3/C electrocatalysts were also studied by cyclic voltammetry, linear sweep, and chronoamperometry. The results show that the Ptx-WO3/C electrocatalysts have higher catalytic activity to ethanol electrooxidation than the commercial Pt/C catalysts; perhaps caused by the “hydrogen spill-over effect.” The reaction mechanisms of the ethanol electro-oxidation on the Ptx-WO3/C were inferred according to the electrochemical characteristics and the data in the reported literature.

Nanocrystalline LiFePO4 and doped LiTi0.01Fe0.99PO4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K -edge X-ray absorption near-edge structure (XANES) measurements show that Ti4+ doping induces an increased unoccupied d-state in LiFePO4, resulting in an enhanced p-type semiconductivity. In situ Fe K -edge XANES measurements of Ti-doped and undoped LiFePO4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both LiFePO4 and doped LiTi0.01Fe0.99PO4 cathodes demonstrate good electrochemical performance.

Co3O4–C composite powder has been synthesized via spray pyrolysis of cobalt nitrate-sugar solution at 600°C and assessed for application as anode materials in Li-ion batteries. Microstructural characterization by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirm an even distribution of carbon throughout particles, as well as the presence of a carbon-based surface sheath surrounding Co3O4–C particle agglomerates. Charge-discharge cycling of half-cells indicates a stable reversible discharge capacity above 800 mAh g−1. Equivalent circuit modeling of Nyquist plots show the Co3O4–C electrode has significant kinetic advantages over non-composite transition metal oxide electrodes.

Co3O4–C composite powder has been synthesized via spray pyrolysis of cobalt nitrate-sugar solution at 600°C and assessed for application as anode materials in Li-ion batteries. Microstructural characterization by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirm an even distribution of carbon throughout particles, as well as the presence of a carbon-based surface sheath surrounding Co3O4–C particle agglomerates. Charge-discharge cycling of half-cells indicates a stable reversible discharge capacity above 800 mAh g−1. Equivalent circuit modeling of Nyquist plots show the Co3O4–C electrode has significant kinetic advantages over non-composite transition metal oxide electrodes.

Nanocrystalline LiFePO4 and doped LiTi0.01Fe0.99PO4 powders were synthesized via a sol-gel preparation route. High-resolution tunneling electron microscopy observation and energy dispersive spectroscopy, mapping show the homogeneous distribution of dopant Ti cations in the crystals. Fe and O K -edge X-ray absorption near-edge structure (XANES) measurements show that Ti4+ doping induces an increased unoccupied d-state in LiFePO4, resulting in an enhanced p-type semiconductivity. In situ Fe K -edge XANES measurements of Ti-doped and undoped LiFePO4 electrodes have been performed to determine the change of Fe valence during the lithium intercalation and de-intercalation processes. Both LiFePO4 and doped LiTi0.01Fe0.99PO4 cathodes demonstrate good electrochemical performance.

Co3O4–C composite powder has been synthesized via spray pyrolysis of cobalt nitrate-sugar solution at 600°C and assessed for application as anode materials in Li-ion batteries. Microstructural characterization by scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy confirm an even distribution of carbon throughout particles, as well as the presence of a carbon-based surface sheath surrounding Co3O4–C particle agglomerates. Charge-discharge cycling of half-cells indicates a stable reversible discharge capacity above 800 mAh g−1. Equivalent circuit modeling of Nyquist plots show the Co3O4–C electrode has significant kinetic advantages over non-composite transition metal oxide electrodes.

Cryogen spray cooling (CSC) is used to minimize the fisk of epidermal damage during dermatologic therapy. However, the dominant mechanisms of heat transfer during the transient cooling process are incompletely understood. The objective of this study is to elucidate the physics of CSC by measuring the effect of initial substrate temperature (T-0) on cooling dynamics. Cryogen was delivered by a straight-tube nozzle onto a skin phantom. A fast-response thermocouple was used to record the phantom temperature changes before. during and after the cryogen spray. Surface heat fluxes (q") and heat-transfer coefficients (h) were computed using an inverse heat conduction algorithm. The maximum surface heat flux (q"(max)) was observed to increase with T-0. The surface temperature corresponding to q" also increased with T-0 but the latter has no significant effect on h. It is concluded that heat transfer between the cryogen spray and skin phantom remains in the nucleate boiling region even if T-0 is 80 degreesC.

Cryogen spray cooling (CSC) is used to minimize the fisk of epidermal damage during dermatologic therapy. However, the dominant mechanisms of heat transfer during the transient cooling process are incompletely understood. The objective of this study is to elucidate the physics of CSC by measuring the effect of initial substrate temperature (T-0) on cooling dynamics. Cryogen was delivered by a straight-tube nozzle onto a skin phantom. A fast-response thermocouple was used to record the phantom temperature changes before. during and after the cryogen spray. Surface heat fluxes (q") and heat-transfer coefficients (h) were computed using an inverse heat conduction algorithm. The maximum surface heat flux (q"(max)) was observed to increase with T-0. The surface temperature corresponding to q" also increased with T-0 but the latter has no significant effect on h. It is concluded that heat transfer between the cryogen spray and skin phantom remains in the nucleate boiling region even if T-0 is 80 degreesC.

WS2 nanotubes were synthesized by sintering amorphous WS3 at high temperature under flowing hydrogen. High-resolution transmission electron microscopy observation revealed that the as-prepared WS2 nanotubes have an open end with an inner hollow core of about 4.6 nm. We studied the lithium intercalation behavior of WS2 nanotubes. The WS2 nanotubes demonstrated a stable cyclability in a wide voltage range ~0.1-3.1 V vs. Li/Li1). The nanotubes could provide a new class of electrode materials for lithium-ion batteries.

WS2 nanotubes were synthesized by sintering amorphous WS3 at high temperature under flowing hydrogen. High-resolution transmission electron microscopy observation revealed that the as-prepared WS2 nanotubes have an open end with an inner hollow core of about 4.6 nm. We studied the lithium intercalation behavior of WS2 nanotubes. The WS2 nanotubes demonstrated a stable cyclability in a wide voltage range ~0.1-3.1 V vs. Li/Li1). The nanotubes could provide a new class of electrode materials for lithium-ion batteries.

A series of LiMxFe12xPO4 (M 5 Mg,Zr,Ti) phosphates were synthesized via a sol-gel method. Transmission electron microscopy observations show that LiMxFe12xPO4 particles consist of nanosize crystals, ranging from 40 to 150 nm. High-resolution TEM analysis reveals that a layer of amorphous carbon was coated on the surface of the LiMxFe12xPO4 particles, which substantially increases the electronic conductivity of LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 powders are phase pure. Near full capacity ~170 mAh/g! was achieved at the C/8 rate at room temperature for LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 electrodes demonstrated better electrochemical performance than that of undoped LiFePO4 at high rate.

Nanocrystalline Si-mesocarbon microbeads ~MCMB! composite anode materials were prepared by ballmilling. Scanning electron microscopic observation showed that the spherical shape of MCMB particles can be retained via moderate ballmilling. Ballmilling conditions have an impact on the capacity and cyclability of nanocrystalline Si-MCMB composites. The optimized Si-MCMB composite anode demonstrated a reversible capacity of 1066 mAh/g with good cyclability. A reaction model has been proposed to explain the reaction mechanisms of lithium insertion and extraction in the Si-MCMB electrode.

WS2 nanotubes were synthesized by sintering amorphous WS3 at high temperature under flowing hydrogen. High-resolution transmission electron microscopy observation revealed that the as-prepared WS2 nanotubes have an open end with an inner hollow core of about 4.6 nm. We studied the lithium intercalation behavior of WS2 nanotubes. The WS2 nanotubes demonstrated a stable cyclability in a wide voltage range ~0.1-3.1 V vs. Li/Li1). The nanotubes could provide a new class of electrode materials for lithium-ion batteries.

Nanocrystalline Si-mesocarbon microbeads ~MCMB! composite anode materials were prepared by ballmilling. Scanning electron microscopic observation showed that the spherical shape of MCMB particles can be retained via moderate ballmilling. Ballmilling conditions have an impact on the capacity and cyclability of nanocrystalline Si-MCMB composites. The optimized Si-MCMB composite anode demonstrated a reversible capacity of 1066 mAh/g with good cyclability. A reaction model has been proposed to explain the reaction mechanisms of lithium insertion and extraction in the Si-MCMB electrode.

A series of LiMxFe12xPO4 (M 5 Mg,Zr,Ti) phosphates were synthesized via a sol-gel method. Transmission electron microscopy observations show that LiMxFe12xPO4 particles consist of nanosize crystals, ranging from 40 to 150 nm. High-resolution TEM analysis reveals that a layer of amorphous carbon was coated on the surface of the LiMxFe12xPO4 particles, which substantially increases the electronic conductivity of LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 powders are phase pure. Near full capacity ~170 mAh/g! was achieved at the C/8 rate at room temperature for LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 electrodes demonstrated better electrochemical performance than that of undoped LiFePO4 at high rate.

Nanocrystalline Si-mesocarbon microbeads ~MCMB! composite anode materials were prepared by ballmilling. Scanning electron microscopic observation showed that the spherical shape of MCMB particles can be retained via moderate ballmilling. Ballmilling conditions have an impact on the capacity and cyclability of nanocrystalline Si-MCMB composites. The optimized Si-MCMB composite anode demonstrated a reversible capacity of 1066 mAh/g with good cyclability. A reaction model has been proposed to explain the reaction mechanisms of lithium insertion and extraction in the Si-MCMB electrode.

A series of LiMxFe12xPO4 (M 5 Mg,Zr,Ti) phosphates were synthesized via a sol-gel method. Transmission electron microscopy observations show that LiMxFe12xPO4 particles consist of nanosize crystals, ranging from 40 to 150 nm. High-resolution TEM analysis reveals that a layer of amorphous carbon was coated on the surface of the LiMxFe12xPO4 particles, which substantially increases the electronic conductivity of LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 powders are phase pure. Near full capacity ~170 mAh/g! was achieved at the C/8 rate at room temperature for LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 electrodes demonstrated better electrochemical performance than that of undoped LiFePO4 at high rate.

A series of LiMxFe12xPO4 (M 5 Mg,Zr,Ti) phosphates were synthesized via a sol-gel method. Transmission electron microscopy observations show that LiMxFe12xPO4 particles consist of nanosize crystals, ranging from 40 to 150 nm. High-resolution TEM analysis reveals that a layer of amorphous carbon was coated on the surface of the LiMxFe12xPO4 particles, which substantially increases the electronic conductivity of LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 powders are phase pure. Near full capacity ~170 mAh/g! was achieved at the C/8 rate at room temperature for LiMxFe12xPO4 electrodes. The doped LiMxFe12xPO4 electrodes demonstrated better electrochemical performance than that of undoped LiFePO4 at high rate.

WS2 nanotubes were synthesized by sintering amorphous WS3 at high temperature under flowing hydrogen. High-resolution transmission electron microscopy observation revealed that the as-prepared WS2 nanotubes have an open end with an inner hollow core of about 4.6 nm. We studied the lithium intercalation behavior of WS2 nanotubes. The WS2 nanotubes demonstrated a stable cyclability in a wide voltage range ~0.1-3.1 V vs. Li/Li1). The nanotubes could provide a new class of electrode materials for lithium-ion batteries.

Nanocrystalline Si-mesocarbon microbeads ~MCMB! composite anode materials were prepared by ballmilling. Scanning electron microscopic observation showed that the spherical shape of MCMB particles can be retained via moderate ballmilling. Ballmilling conditions have an impact on the capacity and cyclability of nanocrystalline Si-MCMB composites. The optimized Si-MCMB composite anode demonstrated a reversible capacity of 1066 mAh/g with good cyclability. A reaction model has been proposed to explain the reaction mechanisms of lithium insertion and extraction in the Si-MCMB electrode.