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21.
随着中国移动数据业务迅速发展,中国移动各地数据机房将陆续建设,如何合理设置机房供电系统,对节能、节地都起着至关重要的作用。本文结合新技术的应用,提出了一种靠、高效、灵活的数据中心机房供电解决方案。 相似文献
22.
Simple self-assembly of SnS2 entrapped graphene aerogel and its enhanced lithium storage performance
《Ceramics International》2016,42(6):6572-6580
In this work, SnS2 nanoplates entrapped graphene aerogel has been successfully prepared by simple self-assembly of reduced graphene oxide obtained through mild chemical reduction. Structural and morphological investigations demonstrated that SnS2 nanoplates are highly dispersed in the three dimensional (3D) porous graphene matrix. When served as anode material for lithium-ion batteries, the electrochemical properties of SnS2/graphene aerogel (SnS2/GA) were evaluated by galvanostatic discharge–charge tests, cyclic voltammetry and impedance spectroscopy measurement. Compared with pristine SnS2, the SnS2/GA nanocomposite achieved a much higher initial reversible capacity (1186 mAh g−1), superior cyclic stability (1004 mAh g−1 after 60 cycles, corresponding to 84.7% of the initial reversible capacity), as well as better rate capability (650 mAh g−1 at a current density of 1000 mA g−1). This significantly improved lithium storage performance can be attributed to the good integration of SnS2 nanoplates with 3D porous graphene network, which can not only provide much more active sites and easy access for Li ions intercalation, but also prevent the aggregation of SnS2 nanoplates and facilitate fast transportation of Li ions and surface electrons during the electrochemical process. 相似文献
23.
In this work Substrate Induced Coagulation (SIC) was used to coat the cathode material LiCoO2, commonly used in Li-ion batteries, with fine nano-sized particulate titania. Substrate Induced Coagulation is a self-assembled dip-coating process capable of coating different surfaces with fine particulate materials from liquid media. A SIC coating consists of thin and rinse-prove layers of solid particles. An advantage of this dip-coating method is that the method is easy and cheap and that the materials can be handled by standard lab equipment. Here, the SIC coating of titania on LiCoO2 is followed by a solid-state reaction forming new inorganic layers and a core-shell material, while keeping the content of active battery material high. This titania based coating was designed to confine the reaction of extensively delithiated (charged) LiCoO2 and the electrolyte. The core-shell materials were characterized by SEM, XPS, XRD and Rietveld analysis. 相似文献
24.
Yaser Hamedi JouybariSirous Asgari 《Journal of power sources》2011,196(1):337-342
Nitrates of lithium, cobalt and nickel are utilized to synthesize LiNi0.8Co0.2O2 cathode material through sol-gel technique. Various synthesis parameters such as calcination time and temperature as well as chelating agent are studied to determine the optimized condition for material processing. Using TG/DTA techniques, the optimized calcination temperatures are selected. Different characterization techniques such as ICP, XRD and TEM are employed to characterize the chemical composition, crystal structure, size and morphology of the powders. Micron and nano-sized powders are produced using citric/oxalic and TEA as chelating agent, respectively. Selected powders are used as cathode material to assemble batteries. Charge-discharge testing of these batteries show that the highest discharge capacity is 173 mAh g−1 at a constant current of 0.1 mA cm−2, between 3.0 and 4.2 V. This is obtained in a battery assembled with the nanopowder produced by TEA as chelating agent. 相似文献
25.
A Li ion polymer battery pack for road vehicles (48 V, 20 Ah) was tested by charging/discharging tests at different current values, in order to evaluate its performance in comparison with a conventional Pb acid battery pack. The comparative analysis was also performed integrating the two storage systems in a hydrogen fuel cell power train for moped applications. The propulsion system comprised a fuel cell generator based on a 2.5 kW polymeric electrolyte membrane (PEM) stack, fuelled with compressed hydrogen, an electric drive of 1.8 kW as nominal power, of the same typology of that installed on commercial electric scooters (brushless electric machine and controlled bidirectional inverter). The power train was characterized making use of a test bench able to simulate the vehicle behaviour and road characteristics on driving cycles with different acceleration/deceleration rates and lengths. The power flows between fuel cell system, electric energy storage system and electric drive during the different cycles were analyzed, evidencing the effect of high battery currents on the vehicle driving range. The use of Li batteries in the fuel cell power train, adopting a range extender configuration, determined a hydrogen consumption lower than the correspondent Pb battery/fuel cell hybrid vehicle, with a major flexibility in the power management. 相似文献
26.
Nano-sized platinum and ruthenium dispersed on the surface LiCoO2 as catalysts for borohydride hydrolysis are prepared by microwave-assisted polyol process. The catalysts are characterized by transmission electron microscopy (TEM), X-ray diffractometry (XRD) and X-ray photoelectron spectroscopy (XPS). Very uniform Pt and Ru nanoparticles with sizes of <10 nm are dispersed on the surface of LiCoO2. XRD patterns show that the Pt/LiCoO2 and Ru/LiCoO2 catalysts only display the characteristic diffraction peaks of a LiCoO2 crystal structure. Results obtained from XPS analysis reveal that the Pt/LiCoO2 and Ru/LiCoO2 catalysts contain mostly Pt(0) and Ru(0), with traces of Pt(IV) and Ru(IV), respectively. The hydrogen generation rates using low noble metal loading catalysts, 1 wt.% Pt/LiCoO2 and 1 wt.% Ru/LiCoO2, are very high. The hydrogen generation rate using Ru/LiCoO2 as a catalyst is slightly higher compared with that of Pt/LiCoO2. 相似文献
27.
A (Ni1/3Co1/3Mn1/3)CO3 precursor with an uniform, spherical morphology was prepared by coprecipitation using a continuously stirred tank reactor method. The as-prepared spherical (Ni1/3Co1/3Mn1/3)CO3 precursor served to produce dense, spherical Li1+x(Ni1/3Co1/3Mn1/3)1−xO2 (0 ≤ x ≤ 0.15) cathode materials. These Li-rich cathodes were also prepared by a second synthesis route that involved the use of an M3O4 (M = Ni1/3Co1/3Mn1/3) spinel compound, itself obtained from the carbonate (Ni1/3Co1/3Mn1/3)CO3 precursor. In both cases, the final Li1+x(Ni1/3Co1/3Mn1/3)1−xO2 products were highly uniform, having a narrow particle size distribution (10-μm average particle size) as a result of the homogeneity and spherical morphology of the starting mixed-metal carbonate precursor. The rate capability of the Li1+x(Ni1/3Co1/3Mn1/3)1−xO2 electrode materials, which was significantly improved with increased lithium content, was found to be better in the case of the denser materials made from the spinel precursor compound. This result suggests that spherical morphology, high density, and increased lithium content were key factors in enabling the high rate capabilities, and hence the power performances, of the Li-rich Li1+x(Ni1/3Co1/3Mn1/3)1−xO2 cathodes. 相似文献
28.
Lithium sulfur cells were prepared by composing with sulfur cathode (PEO)6LiBF4 polymer electrolyte and lithium anode. (PEO)6LiBF4 polymer electrolyte was prepared under three different mixing conditions: stirred polymer electrolyte (SPE), ball-milled polymer electrolyte (BPE) and ball-milled polymer electrolyte with 10 wt%Al2O3 (BCPE). The effects of ball milling and additive were investigated by discharge test according to depth of discharge. The initial discharge capacity of lithium sulfur cell using BCPE was 1670 mAh g−1-sulfur, which was better than those of SPE and BPE, and approximately equal to the theoretical capacity. The cycle performance of Li/(PEO)6LiBF4/S cell was remarkably improved by the addition of Al2O3. 相似文献
29.
A novel synthesis method of thin-film composite Sn/C anodes for lithium batteries is reported. Thin layers of graphitic carbon decorated with uniformly distributed Sn nanoparticles were synthesized from a solid organic precursor Sn(IV) tert-butoxide by a one-step microwave plasma chemical vapor deposition (MPCVD). The thin-film Sn/C electrodes were electrochemically tested in lithium half cells and produced a reversible capacity of 423 and 297 mAh g−1 at C/25 and 5C discharge rates, respectively. A long-term cycling of the Sn/C nanocomposite anodes showed 40% capacity loss after 500 cycles at 1C rate. 相似文献
30.
Richard E. Nygren H. Charles Harjes Peter Wakeland Robert Ellis Henry W. Kugel Robert Kaita Laura Berzak Leonid Zakharov Brian Ehrhart 《Fusion Engineering and Design》2009,84(7-11):1438-1441
The liquid lithium divertor (LLD) to be installed in NSTX has four toroidal panels, each a conical section inclined at 22° like the previous graphite divertor tiles. Each LLD panel is a copper plate clad with 0.25 mm of stainless steel (SS) and a surface layer of flame sprayed molybdenum (Mo) that will host lithium deposited from an evaporator. LITER (evaporators) already used in NSTX will be upgraded for the LLD. Each has twelve 500 W cartridge heaters with thermocouples, 16 other thermocouples, and a channel for helium cooling. During LLD experiments, the LLD will be heated so that the lithium is just above its melting temperature. The length of each shot will be preset to prevent excessive evaporation of lithium from the LLD. This duration depends on the heat load and is likely to be in the range of less than a second to several seconds. Careful thermal control of the LLD is important to maximize the shot times and to guide operation of the LLD. This paper describes the layout of the LLD, its expected thermal performance, the control system, and supporting experiments and analysis. A companion paper in this conference, “Physics design requirements for the national spherical torus experiment liquid lithium divertor,” provides other information. 相似文献