摘要:
An electrode has a front face furthest from the current collector and a back face closest to the current collector and Is disposed on the current collector, and the electrode has a primary gradient of one of a chemical, physical and performance properties of the electroactive particle composition between the front and back faces, with the proviso that the primary gradient is not a bulk porosity gradient. In some embodiments, the electrode further comprises one or more secondary gradients Imposed over the primary gradient. The secondary gradient is one or more gradients selected from the group consisting of particle size gradient, particle size distribution gradient, particle morphology gradient, particle internal porosity, bulk porosity, particle volumetric charge-transfer resistance gradient, particle specific surface area gradient, particle crystalline structure gradient, particle crystallite size gradient, particle chemical composition gradient, particle robustness to cycling gradient, binder gradient, conductive additive gradient, and combinations thereof.
摘要:
Electroactive compositions are disclosed for use in lithium ion battery electrodes. The compositions, such as multifunctional mixed metal olivines, provide an electrochemical cell having a plurality of open circuit voltages at different states of charge. The compositions afford improved state-of-charge monitoring, overcharge protection and/or overdischarge protection for lithium ion batteries.
摘要:
A compact, robust, multifunctional and highly manufacturable rechargeable cylindrical electrochemical cell is provided. In some embodiments, a cell can include a spirally wound assembly having an anode sheet and a cathode sheet separated by separator membranes, each sheet having a electroactive layer on a current collector. At least one of the current collectors can be in electrical communication with conducting tabs that extend from at least one of the anode sheet and the cathode sheet, the conducting tabs extends from an end face of the spirally wound assembly. The centers of the plurality of conducting tabs can be located within a 90 degree quadrant of an end face of the spirally wound assembly.
摘要:
An electrochemical cell, such as Li-Ion, having (a) a positive electrode; (b) a negative electrode, (c) a porous inorganic/organic composite layer interposed between the positive electrode and the negative electrode, and (d) an electrolyte comprising a lithium salt and a non-aqueous solvent. The composite layer includes inorganic nanoparticles and a binder to form a nanocomposite separator (NCS). In addition to the composite layer, the electrochemical cell includes a porous separator.
摘要:
Processes for the fabrication of MgB2 powder and wires are provided. Powders are produced by mechanically alloying magnesium- and boron-containing precursors under controlled conditions to avoid secondary phase and impurity formation. Powders are also prepared by vapor phase reaction of volatile magnesium- and boron-containing precursors. Wires, tapes, films and coatings are provided.
摘要:
A modified powder-in-tube process produces a superconductor wire having a significantly greater current density than will a superconductor wire of the same nominal superconductor composition produced using conventional draw-swage-extrude-roll deformation. In the process disclosed, a superconductor precursor is placed within a ductile tube, the tube with the powder therein is then deformed into a cross-section substantially corresponding to that of the end product, and the deformed tube is then subject to a plurality of heat treatments to convert the precursor into the desired superconducting ceramic oxide phase. Before the last of the heat treatments, the tube is isostatically pressed to densify and texture the superconductor precursor oxide in the tube.
摘要:
A method for preparing a BSCCO-2223 oxide superconducting article includes annealing an oxide superconductor article comprised of BSCCO-2223 oxide superconductor at a temperature selected from the range of about 500° C.≦T≦787° C. and an annealing atmosphere having an oxygen pressure selected from within the region having a lower bound defined by the equation, PO2(lower)≧3.5×1010 exp(−32,000/T+273) and an upper bound defined by the equation, PO2(upper)≦1.1×1012 exp(−32,000/T+273). The article is annealed for a time sufficient to provide at least a 10% increase in critical current density as compared to the critical current density of the pre-anneal oxide superconductor article. An oxide superconductor having the formula Bi2−yPbySr2Ca2Cu3O10+x, where 0≦x≦1.5 and where 0≦y≦0.6 is obtained, the oxide superconductor characterized by a critical transition temperature of greater than 111.0 K, as determined by four point probe method.
摘要翻译:制备BSCCO-2223氧化物超导制品的方法包括在选自约500℃的温度范围内对由BSCCO-2223氧化物超导体组成的氧化物超导体制品进行退火。<= T <= 787℃和退火气氛 PO2(下)> = 3.5×10 10 exp(-32,000 / T + 273)和由上式定义的上限的PO2(上)<= 1.1×1012 exp(-32,000 / T + 273)。 与预退火氧化物超导体制品的临界电流密度相比,该制品退火足以提供临界电流密度至少10%的时间。 具有式Bi2-yPbySr2Ca2Cu3O10 + x的氧化物超导体,其中0 <= x <= 1.5,其中0 <= y <= 0.6,所述氧化物超导体的特征在于临界转变温度大于111.0K,如由 四点探针法。
摘要:
A cabled conductor is provided for use in a cryogenically cooled circuit including refrigeration having a predetermined operating temperature and efficiency. The conductor includes multiple conductor strands cabled about the longitudinal axis of the conductor at a preselected cabling period, each strand including a composite of superconducting ceramic in intimate contact with conductive matrix material. Each filament has high performance regions in which the filament material is well-textured with its preferred direction aligned perpendicular to the widest longitudinal cross-section of the conductor alternating with poorly superconducting regions which are at least about half the diameter of a filament in length and in which the superconducting ceramic filament is strained by transposition in excess of its critical strain limit. In the poorly superconducting regions, the conductive matrix material provides an alternate current path. The ratio of the average length of the poorly superconducting regions to the preselected cabling period is less than about (&rgr;300e/&rgr;oe)&egr;E, where &rgr;oe is the resistivity of the composite at the operating temperature; &rgr;300e is the resistivity of the composite at 300 Kelvins; and &egr; is the predetermined efficiency of the refrigeration means at its operating temperature. In the preferred embodiment, this ratio is less than 1:4, and preferably less than 1:20.
摘要:
A process for increasing the resistivity of a HTS oxide composite sheath including heating a superconductive HTS oxide composite, the composite including a sheath including silver, in the presence of mercury at temperatures sufficient to form a silver--mercury alloy is provided together with a HTS oxide composite which includes a high temperature superconductor oxide core surrounded by a metallic sheath, the metallic sheath including silver and mercury.Also provided is a process for preparing a HTS oxide composite having an enhanced transport critical current density including placing the HTS oxide composite within a sealed, evacuated container, and, heating the HTS oxide composite for time and at temperatures sufficient for enhancement of transport critical current density in comparison to the transport critical current density of the HTS oxide composite prior to the heating.
摘要:
A novel process of the production and processing of high quality, high T.sub.c (Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. The sealed sheath is deformed to form an elongated precursor article of a desired texture; and thereafter heated at a third selected processing temperature in an inert atmosphere with a third selected oxygen partial pressure for a third selected time period. The third processing temperature and third oxygen partial pressure are cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.