Metallic nanoparticle （NP） shapes have a significant influence on the property of composite embedded with metallic NPs. Swift heavy ion irradiation is an effective way to modify shapes of metallic NPs embedded in an...Metallic nanoparticle （NP） shapes have a significant influence on the property of composite embedded with metallic NPs. Swift heavy ion irradiation is an effective way to modify shapes of metallic NPs embedded in an amorphous matrix. We investigate the shape deformation of Ag NPs with irradiation fluence, and 357 MeV Ni ions are used to irradiate the silica containing Ag NPs, which are prepared by ion implantation and vacuum annealing. The UV-vis results show that the surface plasmon resonance （SPR） peak from Ag NPs shifts from 400 to 377nm. The SPR peak has a significant shift at fluence lower than 1 × 10^14 ions/cm2 and shows less shift at fluence higher than 1 × 10^14 ions/cm2. The TEM results reveal that the shapes of Ag NPs also show significant deformation at fluence lower than 1 × 10^14 ions/cm2 and show less deformation at fluence higher than 1 × 10^14 ions/cm2. The blue shift of the SPR peak is considered to be the consequence of defect production and Ag NP shape deformation, Based on the thermal spike model calculation, the temperature of the silica surrounding Ag particles first increases rapidly, then the region of Ag NPs close to the interface of Ag/silica is gradually heated. Therefore, the driven force of Ag NPs deformation is considered as the volume expansion of the first heated silica layer surrounding Ag NPs.展开更多
The removal of Ni ion from an aqueous solution was carried out by solvent sublation of Ni-diacetyldioximesodium dodecylbenzensulphonic （sublate） into isopentanol. The ratio of surfactant to Ni-diacetyldioxime comple...The removal of Ni ion from an aqueous solution was carried out by solvent sublation of Ni-diacetyldioximesodium dodecylbenzensulphonic （sublate） into isopentanol. The ratio of surfactant to Ni-diacetyldioxime complex at 20：1 was most effective for the removal, with over 90% Ni ion removed from the aqueous solution within 1 h. The effects of electrolytes （e.g. NaCl）, non-hydrophobic organics （e.g. ethanol） and pH of the solution upon the process were well studied. The removal rate was enhanced by higher airflow rates but almost independent on the volume of the organic solvent floating on the top of the aqueous column. The process of solvent sublation followed first order kinetics. A characteristic parameter, the apparent activation energy of attachment of the sublate to bubbles, was estimated to be 8.99 kJ/mol. Furthermore, the simulation of a mathematical model with the experiment data on the solvent sublation of Ni-diacetyldioxime-SDS was proved to be validated.展开更多
将醋酸镍和葡萄糖溶于水中,与氧化石墨烯(GO)水悬浮液均匀混合,在180℃下水热处理24 h,再在Ar中700℃下炭化3 h,然后在空气中300℃下煅烧3 h得到三维Ni/NiO@C/GN。结果表明,水热处理过程中葡萄糖衍生的炭层将Ni(OH)2完全包裹,并在炭化...将醋酸镍和葡萄糖溶于水中,与氧化石墨烯(GO)水悬浮液均匀混合,在180℃下水热处理24 h,再在Ar中700℃下炭化3 h,然后在空气中300℃下煅烧3 h得到三维Ni/NiO@C/GN。结果表明,水热处理过程中葡萄糖衍生的炭层将Ni(OH)2完全包裹,并在炭化过程中转化为金属Ni,部分金属Ni在空气中煅烧中被氧化为NiO。当作为锂离子电池的负极材料时,其初始容量为711.6 mA h g^(-1),300次循环后增加到772.1 mA h g^(-1)。作为对比,没有添加GO的材料的初始容量较低,仅为584.7 mA h g^(-1),300次循环后下降到148.8 mA h g^(-1)。这些结果表明炭层可以抑制Ni/NiO纳米颗粒的团聚,有效缓解锂化过程中的体积膨胀,抑制循环过程中的电极开裂。GO的加入可形成丰富的导电网络,提高导电性。较大的比表面积可增加活性位点,有利于电解液快速浸润电极材料。这些因素显著改善了Ni/NiO@C/GN负极的电化学性能。展开更多
The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, wher...The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.展开更多
This paper investigates the mechanism of Li insertion into interphase Ni3Sn in Ni-Sn alloy for the anode of lithium ion battery by means of the first-principles plane-wave pseudopotential. Compared with other phases, ...This paper investigates the mechanism of Li insertion into interphase Ni3Sn in Ni-Sn alloy for the anode of lithium ion battery by means of the first-principles plane-wave pseudopotential. Compared with other phases, it is found that the Ni3Sn has larger relative expansion ratio and lower electrochemical potential, with its specific plateaus voltage around 0.3 eV when lithium atoms are filled in all octahedral interstitial sites, and the relative expansion ratio increasing dramatically when the lithiated phase transits from octahedral interstitial sites to tetrahedral interstitial sites. So this phase is a devastating phase for whole alloy electrode materials.展开更多
The growing global demands of safe, low-cost and high working voltage energy storage devices trigger strong interests in novel battery concepts beyond state-of-art lithium-ion battery. Herein, a dualion battery based ...The growing global demands of safe, low-cost and high working voltage energy storage devices trigger strong interests in novel battery concepts beyond state-of-art lithium-ion battery. Herein, a dualion battery based on nanostructured Ni_3S_2/Ni foam@RGO(NSNR) composite anode is developed, utilizing graphite as cathode material and LiPF6-VC-based solvent as electrolyte. The battery operates at high working voltage of 4.2–4.5 V, with superior discharge capacity of ～90 m A h g^(-1) at 100 mA g^(-1), outstanding rate performance, and long-term cycling stability over 500 cycles with discharge capacity retention of ～85.6%. Moreover, the composite simultaneously acts as the anode material and the current collector, and the corrosion phenomenon can be greatly reduced compared to metallic Al anode. Thus, this work represents a significant step forward for practical safe, low-cost and high working voltage dual-ion batteries,showing attractive potential for future energy storage application.展开更多
The Ni80Nb20 films were prepared by ion beam assisted deposition (IBAD) with various Ar+ ion energies. A phase evolution of fcc→amorphous→Ni+Nb→Ni+hcp was observed with the increasing of ion beam energy from 2 keV ...The Ni80Nb20 films were prepared by ion beam assisted deposition (IBAD) with various Ar+ ion energies. A phase evolution of fcc→amorphous→Ni+Nb→Ni+hcp was observed with the increasing of ion beam energy from 2 keV to 8 keV. When bombarded by Ar+ ions of 8 keV during deposition, a new crystalline phase with hcp structure was obtained, of which the lattice parameters are a=0.286 nm and c=0.483 nm, different from those of the similar A3B-type hcp phase previously reported. The experimental results were discussed in terms of thermodynamics and restricted kinetic conditions in the far-from-equilibrium process of IBAD. The formation of hep phase may also be related to the valence electron effect.展开更多
Spinel LiNi0.05Mn1.95O4 cathode material for lithium ion batteries was synthesized by solid-state reaction from coprecipitated Ni-Mn hydroxide precursors and characterized by X-ray diffraction(XRD),scanning electron m...Spinel LiNi0.05Mn1.95O4 cathode material for lithium ion batteries was synthesized by solid-state reaction from coprecipitated Ni-Mn hydroxide precursors and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and galvanostatic charge-discharge tests. It is found that LiNi0.05Mn1.95O4 powder has an ordered cubic spinel phase(space group Fd 3m) and exhibits superior rate capability. After 450 cycles,the LiNi0.05Mn1.95O4/carbonaceous mesophase spheres(CMS) Li-ion batteries can retain 96.0% and 93.3% capacity at 5C and 10C charge/discharge rate,respectively,compared with 85.3%(5C) and 80.5%(10C) retention for LiMn2O4 batteries. However,the initial discharge capacity of LiNi0.05Mn1.95O4/CMS batteries at 1C charge/discharge rate(96.20 mA·h/g) is slightly lower than that of the LiMn2O4 batteries(100.98 mA·h/g) due to the increased average oxidation state of Mn in LiNi0.05Mn1.95O4.展开更多
Spherical Ni(OH)2 powder coated with Co(OH)2 as raw material was mixed with LiOH to synthesize cathode material for lithium ion battery by using solid-state reaction. After sintered at temperature above 600 ℃, a soli...Spherical Ni(OH)2 powder coated with Co(OH)2 as raw material was mixed with LiOH to synthesize cathode material for lithium ion battery by using solid-state reaction. After sintered at temperature above 600 ℃, a solid solution with layer structure was formed. The result of XPS shows that it is a concentration gradient material with higher cobalt content at the surface, and the gradient decreases with increasing sintering temperature from 650 to 750 ℃. This new gradient material, called as Co-coated LiNiO2, exhibits excellent electrochemical performances for the cathode of Li-ion batteries in comparison with LiNiO2 and Co-doping LiNiO2. The discharge capacity of Co-coated LiNiO2 is over 180 mA·h/g and capacity decay per cycle is less than 0.07% when Co-coated LiNiO2 consisting of 92% nickel and 8% cobalt was sintered at the temperatures between 650-670 ℃. Though initial discharge capacity could be increased with higher sintering temperature, the cycle life would be reduced.展开更多
X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic r...X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion （Al^9＋ and Al^11＋ ） charge states of the target ion （Al^10＋） are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 11475230 and U1532262
文摘Metallic nanoparticle （NP） shapes have a significant influence on the property of composite embedded with metallic NPs. Swift heavy ion irradiation is an effective way to modify shapes of metallic NPs embedded in an amorphous matrix. We investigate the shape deformation of Ag NPs with irradiation fluence, and 357 MeV Ni ions are used to irradiate the silica containing Ag NPs, which are prepared by ion implantation and vacuum annealing. The UV-vis results show that the surface plasmon resonance （SPR） peak from Ag NPs shifts from 400 to 377nm. The SPR peak has a significant shift at fluence lower than 1 × 10^14 ions/cm2 and shows less shift at fluence higher than 1 × 10^14 ions/cm2. The TEM results reveal that the shapes of Ag NPs also show significant deformation at fluence lower than 1 × 10^14 ions/cm2 and show less deformation at fluence higher than 1 × 10^14 ions/cm2. The blue shift of the SPR peak is considered to be the consequence of defect production and Ag NP shape deformation, Based on the thermal spike model calculation, the temperature of the silica surrounding Ag particles first increases rapidly, then the region of Ag NPs close to the interface of Ag/silica is gradually heated. Therefore, the driven force of Ag NPs deformation is considered as the volume expansion of the first heated silica layer surrounding Ag NPs.
基金This work was supported by the Natural Science Foundation of Guangdong Province （No.04300883） Science and Technology Program of Shenzhen （No.200502）.
文摘The removal of Ni ion from an aqueous solution was carried out by solvent sublation of Ni-diacetyldioximesodium dodecylbenzensulphonic （sublate） into isopentanol. The ratio of surfactant to Ni-diacetyldioxime complex at 20：1 was most effective for the removal, with over 90% Ni ion removed from the aqueous solution within 1 h. The effects of electrolytes （e.g. NaCl）, non-hydrophobic organics （e.g. ethanol） and pH of the solution upon the process were well studied. The removal rate was enhanced by higher airflow rates but almost independent on the volume of the organic solvent floating on the top of the aqueous column. The process of solvent sublation followed first order kinetics. A characteristic parameter, the apparent activation energy of attachment of the sublate to bubbles, was estimated to be 8.99 kJ/mol. Furthermore, the simulation of a mathematical model with the experiment data on the solvent sublation of Ni-diacetyldioxime-SDS was proved to be validated.
文摘将醋酸镍和葡萄糖溶于水中,与氧化石墨烯(GO)水悬浮液均匀混合,在180℃下水热处理24 h,再在Ar中700℃下炭化3 h,然后在空气中300℃下煅烧3 h得到三维Ni/NiO@C/GN。结果表明,水热处理过程中葡萄糖衍生的炭层将Ni(OH)2完全包裹,并在炭化过程中转化为金属Ni,部分金属Ni在空气中煅烧中被氧化为NiO。当作为锂离子电池的负极材料时,其初始容量为711.6 mA h g^(-1),300次循环后增加到772.1 mA h g^(-1)。作为对比,没有添加GO的材料的初始容量较低,仅为584.7 mA h g^(-1),300次循环后下降到148.8 mA h g^(-1)。这些结果表明炭层可以抑制Ni/NiO纳米颗粒的团聚,有效缓解锂化过程中的体积膨胀,抑制循环过程中的电极开裂。GO的加入可形成丰富的导电网络,提高导电性。较大的比表面积可增加活性位点,有利于电解液快速浸润电极材料。这些因素显著改善了Ni/NiO@C/GN负极的电化学性能。
基金supported by the National Natural Science Foundation of China(no.51362018)the Foundation for Innovation Groups of Basic Research in Gansu Province(no.1606RJIA322)
文摘The CoO/CoVO/Ni nanocomposites were rationally designed and prepared by a two-step hydrothermal synthesis and subsequent annealing treatment. The one-dimensional（1D） CoOnanowire arrays directly grew on Ni foam, whereas the 1D CoVOnanowires adhered to parts of CoOnanowires.Most of the hybrid nanowires were inlayed with each other, forming a 3D hybrid nanowires network.As a result, the discharge capacity of CoO/CoVO/Ni nanocomposites could reach 1201.8 mAh/g after100 cycles at 100 mA/g. After 600 cycles at 1 A/g, the discharge capacity was maintained at 828.1 mAh/g.Moreover, even though the charge/discharge rates were increased to 10 A/g, it rendered reversible capacity of 491.2 mAh/g. The superior electrochemical properties of nanocomposites were probably ascribed to their unique 3D architecture and the synergistic effects of two active materials. Therefore, such CoO/CoVO/Ni nanocomposites could potentially be used as anode materials for high-performance Li-ion batteries.
基金supported by the National Natural Science Foundation of China (Grant No 50771046)the Key Program of Natural Science Foundation of Guangdong Province of China (Grant No 05200534)+1 种基金the Program for Tackling Key Problems of Guangdong Province of China (Grant No 2006A10704003)the Program for Tackling Key Problems of Guangzhou City of China (GrantNo 2006Z3-D2031)
文摘This paper investigates the mechanism of Li insertion into interphase Ni3Sn in Ni-Sn alloy for the anode of lithium ion battery by means of the first-principles plane-wave pseudopotential. Compared with other phases, it is found that the Ni3Sn has larger relative expansion ratio and lower electrochemical potential, with its specific plateaus voltage around 0.3 eV when lithium atoms are filled in all octahedral interstitial sites, and the relative expansion ratio increasing dramatically when the lithiated phase transits from octahedral interstitial sites to tetrahedral interstitial sites. So this phase is a devastating phase for whole alloy electrode materials.
基金supported by the National Natural Science Foundation of China (No. 51725401)the Fundamental Research Funds for the Central Universities (FRF-TP-15-002C1 and FRF-TP17-002C2)
文摘The growing global demands of safe, low-cost and high working voltage energy storage devices trigger strong interests in novel battery concepts beyond state-of-art lithium-ion battery. Herein, a dualion battery based on nanostructured Ni_3S_2/Ni foam@RGO(NSNR) composite anode is developed, utilizing graphite as cathode material and LiPF6-VC-based solvent as electrolyte. The battery operates at high working voltage of 4.2–4.5 V, with superior discharge capacity of ～90 m A h g^(-1) at 100 mA g^(-1), outstanding rate performance, and long-term cycling stability over 500 cycles with discharge capacity retention of ～85.6%. Moreover, the composite simultaneously acts as the anode material and the current collector, and the corrosion phenomenon can be greatly reduced compared to metallic Al anode. Thus, this work represents a significant step forward for practical safe, low-cost and high working voltage dual-ion batteries,showing attractive potential for future energy storage application.
基金The work was supported in part by the National Natural Sci ence Foundation of China(No.19875027)The Ministry of Science and Technology of China(No.G200067207-1),by the Adninistration of Tsinghua University.
文摘The Ni80Nb20 films were prepared by ion beam assisted deposition (IBAD) with various Ar+ ion energies. A phase evolution of fcc→amorphous→Ni+Nb→Ni+hcp was observed with the increasing of ion beam energy from 2 keV to 8 keV. When bombarded by Ar+ ions of 8 keV during deposition, a new crystalline phase with hcp structure was obtained, of which the lattice parameters are a=0.286 nm and c=0.483 nm, different from those of the similar A3B-type hcp phase previously reported. The experimental results were discussed in terms of thermodynamics and restricted kinetic conditions in the far-from-equilibrium process of IBAD. The formation of hep phase may also be related to the valence electron effect.
文摘Spinel LiNi0.05Mn1.95O4 cathode material for lithium ion batteries was synthesized by solid-state reaction from coprecipitated Ni-Mn hydroxide precursors and characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and galvanostatic charge-discharge tests. It is found that LiNi0.05Mn1.95O4 powder has an ordered cubic spinel phase(space group Fd 3m) and exhibits superior rate capability. After 450 cycles,the LiNi0.05Mn1.95O4/carbonaceous mesophase spheres(CMS) Li-ion batteries can retain 96.0% and 93.3% capacity at 5C and 10C charge/discharge rate,respectively,compared with 85.3%(5C) and 80.5%(10C) retention for LiMn2O4 batteries. However,the initial discharge capacity of LiNi0.05Mn1.95O4/CMS batteries at 1C charge/discharge rate(96.20 mA·h/g) is slightly lower than that of the LiMn2O4 batteries(100.98 mA·h/g) due to the increased average oxidation state of Mn in LiNi0.05Mn1.95O4.
文摘Spherical Ni(OH)2 powder coated with Co(OH)2 as raw material was mixed with LiOH to synthesize cathode material for lithium ion battery by using solid-state reaction. After sintered at temperature above 600 ℃, a solid solution with layer structure was formed. The result of XPS shows that it is a concentration gradient material with higher cobalt content at the surface, and the gradient decreases with increasing sintering temperature from 650 to 750 ℃. This new gradient material, called as Co-coated LiNiO2, exhibits excellent electrochemical performances for the cathode of Li-ion batteries in comparison with LiNiO2 and Co-doping LiNiO2. The discharge capacity of Co-coated LiNiO2 is over 180 mA·h/g and capacity decay per cycle is less than 0.07% when Co-coated LiNiO2 consisting of 92% nickel and 8% cobalt was sintered at the temperatures between 650-670 ℃. Though initial discharge capacity could be increased with higher sintering temperature, the cycle life would be reduced.
文摘X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion （Al^9＋ and Al^11＋ ） charge states of the target ion （Al^10＋） are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes.
