Abstract: We have measured the electrical characteristics and the efficiencies of single-layer organic light-emitting diodes based on poly[2-methoxy-5-(2-ethylhexoxy)-1,4-phenylene vinylene] (MEH-PPV), with Au anodes and Ca, Al, and Au cathodes. We show that proper accounting of the built-in potential leads to a consistent description of the current-voltage data. For the case of Au and Al cathodes, the current under forward bias is dominated by holes injected from the anode and is space-charge limited with a field-dependent hole mobility. The Ca cathode is capable of injecting a space-charge-limited electron current.

Abstract: Ammonia was synthesized from its elements at atmospheric pressure in a solid state proton (H+)-conducting cell-reactor. Hydrogen was flowing over the anode and was converted into protons that were transported through the solid electrolyte and reached the cathode (palladium) over which nitrogen was passing. At 570 degreesC and atmospheric pressure, greater than 78 percent of the electrochemically supplied hydrogen was converted into ammonia. The thermodynamic requirement for a high-pressure process is eliminated.

Abstract: An along-the-channel model is developed for evaluating the effects of various design and operating parameters on the performance of a proton exchange membrane (PEM) fuel cell. The model, which is based on a previous one, has been extended to include the convective water transport across the membrane by a pressure gradient, temperature distribution in the solid phase along the flow channel, and heat removal by natural convection and coflow and counterflow heat exchangers. Results from the model show that the performance of a PEM fuel cell could be improved by anode humidification and positive differential pressure between the cathode and anode to increase the back transport rate of water across the membrane. Results also show that effective heat removal is necessary for preventing excessive temperature which could lead to local membrane dehydration. For heat removal and distribution, the counterflow heat exchanger is most effective.

Abstract: A lithium secondary battery provided with an anode containing lithium titanate as an active material, cathode containing a carbon material as an active material, and electrolyte prepared by dissolving a lithium salt in an organic solvent It is preferable to use a lithium titanate having a composition expressed by the generalized formula of Lix Tiy O4 (08≤x≤14 and 16≤y≤22) The lithium secondary battery having a rated voltage of 15 V has a high capacity and excellent charging/discharging cycle characteristics suitable for power sources of wrist watches, etc

Abstract: This article concerns the foundations of a new technology for surface modification of metallic materials based on the use of original sources of low-energy, high-current electron beams. The sources contain an electron gun with an explosive-emission cathode and a plasma anode, placed in a guide magnetic field. The acceleration gap and the transportation channel are prefilled with plasma with the use of spark plasma sources or a low-pressure reflected discharge. The electron-beam sources produce electron beams with the parameters as follows: electron energy 10–40 keV; pulse duration 0.5–5 μs; energy density 0.5–40 J/cm2, and beam cross-section area 10–50 cm2. They are simple and reliable in operation. Investigations performed with a variety of constructional and tool materials (steels, aluminum and titanium alloys, hard alloys) have shown that the most pronounced changes of the structure-phase state occur in the near-surface layers quenched from the liquid state, where the crystallization front velocity rea...

Abstract: PROBLEM TO BE SOLVED: To provide a secondary battery with high capacity and high energy density. SOLUTION: In a secondary battery comprising a cathode for which an active material having lithium-absorptive and desorptive property is used, an anode, and a lithium ion movable solvent, an intermetallic compound, consisting of one or more elements selected from Al, Ge, Pb, Si, Sn, and Zn and either a metal excepting these metals or a semimetal is used for an anode active material of this secondary battery. Especially, an anode active material having low crystallinity or being amorphous is used for the secondary battery. Consequently, the secondary battery obtained has markedly high capacity and high energy density, as compared with a secondary battery using a carbon-type anode and has superior cycle property as compared with a secondary battery using an alloy anode.

Abstract: The appearance of an extra arc in impedance spectra obtained on high performance solid oxide fuel cell (SOFC) anodes is recognized when experiments are conducted in a test setup where the working and reference electrodes are placed in separate atmospheres. A simple continuously stirred tank reactor (CSTR) model is used to illustrate how anodes measured with the reference electrode in an atmosphere separate from the working electrode are subject to an impedance contribution from gas conversion. The gas conversion impedance is split into a resistive and a capacitive part, and the dependences of these parameters on gas composition, temperature, gas flow rate, and rig geometry are quantified. The fuel gas flow rate per unit of anode area is decisive for the resistivity, whereas the capacitance is proportional to the CSTR volume of gas over the anode. The model predictions are compared to actual measurements on Ni/yttria stabilized zirconia cermet anodes for SOFC. The contribution of the gas conversion overpotential to dc current-voltage characteristics is deduced for H{sub 2}/H{sub 2}O and shown to have a slope of RT/2F in a Tafel plot.

Abstract: A new method of measuring current distribution in a polymer electrolyte fuel cell of active area 100cm2 has been demonstrated, using a printed circuit board (PCB) technology to segment the current collector and flow field. The PCB technique was demonstrated to be an effective approach to fabricating a segmented electrode and provide a useful tool for analysing cell performance at different reactant gas flow rates and humidification strategies. In this initial chapter of work with the segmented cell, we describe measured effects on current distribution of cathode and anode gas stream humidification levels in a hydrogen/air cell, utilizing a NafionTM 117 membrane and single serpentine channel flow fields, and operating at relatively high gas flow rates. Effects of the stoichiometric flow of air are also shown. A clear trend is seen, apparently typical for a thick ionomeric membrane, of lowering in membrane resistance down the flow channel, bringing about the highest local current density near the air outlet. This trend is reversed at low stoichiometric flows of air. At an air flow rate less than three times stoichiometry, the local performance starts to drop significantly from inlet to outlet, as local oxygen concentration drop overshadows the lowering in resistance along the direction of flow.

Abstract: The invention relates to thin film solid state electrochemical cells consisting of a lithium metal anode, a polymer electrolyte and a cathode, where the lithium anode has been stabilized with a polymer film capable of transmitting lithium ions. Methods for making battery cells using the anode stabilizing films of the invention are disclosed.

Abstract: A programmable sub-surface aggregating metallization structure (100) includes an ion conductor (110) such as a chalcogenide glass which includes metal ions and at least two electrodes (120, 130) disposed at opposing surfaces of the ion conductor (110). Preferably, the ion conductor (110) includes a chalcogenide material with Group IB or Group IIB metals. One of the two electrodes (120, 130) is preferably configured as a cathode and the other as an anode. When a voltage is applied to between the anode and cathode, a metal dendrite (140) grows from the cathode through the ion conductor (11) toward the anode. The grow rate of the dendrite may be stopped by removing the voltage or the dendrite may be retracted back toward the cathode by reversing the voltage polarity at the anode and the cathode. When a voltage is applied for a sufficient length of time, a continuous metal dendrite grows through the ion conductor (110) and connects the electrodes (120, 130), thereby shorting the device. The continuous metal dendrite then can be broken by applying another voltage.

Abstract: The electrochemical oxidation of phenol in an aqueous solution is a complex transformation involving several transfer steps of oxygen atoms and electrons. Transfer of the oxygen atom occurs through the intermediary of hydroxyl radicals adsorbed on the active sites of the anode. Galvanostatic electrolyses of phenol (10.5 to 105 mmol/dm{sup 3}) in aqueous solution at pH 2 on a Ta/PbO{sub 2} anode were followed by high-pressure liquid chromatography and by analysis of the total organic carbon. Hydroquinone, catechol, 1,4-benzoquinone (1,4-BQ), maleic and fumaric acids, and carbon dioxide are the main products. The nonidentified products consist mainly of polymers. Study of the influence of temperature shows that the rate consumption of phenol initially at 21 mmol/dm{sup 3} is mass transport limited. CO{sub 2} is immediately formed following the 1,4-BQ-maleic acid pathway involving 20 faradays and forming 4 mol of CO{sub 2} and/or the 1,4-BQ-intermediary in C2 pathway at 16 faradays with formation of 2 mol of CO{sub 2}. The faradaic yield values show that a phenol molecule adsorbed on a catalytic site undergoes a succession of oxidation steps involving, on average, five electrons without desorption of the intermediate products. This number of electrons varies according to the operating conditions (temperature, anodicmore » current density, initial phenol concentration, hydrodynamic conditions, etc.). The mean faradaic yield decreases during electrolysis; it can reach 70% at the beginning of electrolysis of a 21 mmol/dm{sup 3} phenol solution for an anodic current density of 100 mA/cm{sup 2}. The phenol conversion into insoluble polymers increases as a function of its initial concentration and the anodic current density but it does not exceed 10%.« less

Abstract: This invention pertains generally to the field of light-emitting diodes, LEDs. More particularly, this invention relates to polymer LEDs which offer high brightness, high efficiency, and extended operating life, and which comprise: a transparent hole-injecting anode layer (11); an emissive layer comprising an electroluminescent polymer (12); and an electron-injecting cathode layer (13); the cathode layer comprises an ultra-thin layer of alkaline earth metal, such as calcium, strontium, and barium, having a thickness of about 100 Angstroms or less, typically from about 15 to about 100 Angstroms.

Abstract: New polymer electrolyte membranes for polymer-electrolyte-membrane (PEM) fuel cells (PEFCs) have been developed Platinum nanocrystals (d = 1--2 nm) were highly dispersed in a Nafion 112 film (Pt-PEM, thickness 50 {micro}m) to catalyze the recombination of the crossover H{sub 2} with O{sub 2}, and the water generated was found to humidify the Pt-PEM directly In order to clarify the self-humidifying properties in the Pt-PEM, the amount of water vapor produced by the recombination and the faradaic reaction was analyzed together with those of consumed H{sub 2} and O{sub 2} by monitoring humidity in the exhausting gases from PEFCs operated with dry H{sub 2} consumption decreased to ca 2/3 of that in normal membranes All H{sub 2}O produced inside the Pt-PEM was found to be exhausted from the anode, resulting in the efficient humidification of the membrane on the anode side, which is dried by electro-osmotic drag Thus, the resistance of the Pt-PEM was lowered to 004 {Omega} cm{sup 2} It is also found that the Pt-PEM improved the cathode potential distinctively, which was ascribed to eliminate of the chemical reaction of crossover gases in the cathode catalyst layer, and eliminated any disturbance of O{sub 2} diffusion by H{sub 2}O vapormore » produced by the reaction The operation of PEFCs with minimal or no humidification by using Pt-PEMs is essential in applications to power sources for electric vehicles or various electronic devices from the viewpoints of the simplification of control systems, cold starts, or response to abrupt load changes« less

Abstract: This invention is an improved fuel cell design for use at low pressure. The invention has a reduced number of component parts to reduce fabrication costs, as well as a simpler design that permits the size of the system to be reduced at the same time as performance is being improved. In the present design, an adjacent anode and cathode pair are fabricated using a common conductive element, with that conductive element serving to conduct the current from one cell to the adjacent one. This produces a small and simple system suitable for operating with gas fuels or alternatively directly with liquid fuels, such as methanol, dimethoxymethane, or trimethoxymethane. The use of these liquid fuels permits the storage of more energy in less volume while at the same time eliminating the need for handling compressed gases which further simplifies the fuel cell system. The electrical power output of the design of this invention can be further increased by adding a passage for cooling the stack through contact with a coolant.

Abstract: Lithium batteries are typically constructed from a lithium cobalt oxide cathode and a carbon anode. We have investigated intermetallic anode materials based on tin, which can provide a high capacity at a slightly higher voltage (400 mV) than metallic lithium and thus reduce the safety concerns associated with the carbon anode. In particular, we have investigated the copper-tin system at around the composition Cu{sub 6}Sn{sub 5} and have determined the effect on cycling and capacity of electrodes with various ratios of copper to tin. Anode compositions that are slightly copper rich (Cu{sub 6}Sn{sub 4}) were found to exhibit greater utilization of the tin than those with the stoichiometric bronze ratio (Cu{sub 6}Sn{sub 5}) or those having a slight excess of tin (Cu{sub 6}Sn{sub 6}). The differences in electrochemical behavior are explained in terms of an inert matrix model.

Abstract: The structural evolution of SnO2 fine powder prepared by a sol-gel method upon heat-treatment was investigated by using x-ray diffraction. Electrochemical measurements showed that the reversible capacity of lithium ion reaction with the SnO2 electrode could be as high as 600 mAh/g. The mechanism of lithium ion reaction was studied by ex situ x-ray diffraction and Raman spectroscopy. Two processes were revealed: a substitution reaction, in which SnO2 is reduced and Sn is formed, followed by LiySn alloy formation.

Abstract: We have succeeded in fabricating a thick-film organic light emitting diode having a doped hole transport layer (DHTL). The basic cell structure is anode DHTL/emitter layer/cathode. The DHTL is composed of a hole transporting polycarbonate polymer (PC-TPB-DEG) and tris(4-bromophenyl)aminium hexachloroantimonate (TBAHA) as a dopant. As an emitter, we used tris(8-hydroxyquinoline) aluminum (Alq). With a 650-nm-thick DHTL, the device showed considerable reduction in cell resistance compared with an anode/nondoped HTL/Alq/cathode device with the same HTL thickness. Although the electroluminescent quantum efficiency ΦL was rather low in the doped device, we should be able to increase it by interposing a thin tetraphenylbendidine (TPB) layer between the DHTL and the emitter layer while keeping the driving voltage low. The anode/DHTL (650 nm)/TPB(50 nm)/Alq(50 nm)/cathode showed luminance of more than 4004 cd/m2 at 10.0 V and 220 mA/cm2.

Abstract: Micron-sized Li 4 Ti 5 O 12 was prepared in a single-step solid-state reaction involving TiO 2 and Li 2 CO 3 , and its electrochemical behavior was evaluated in Li and Li-ion cells containing a polyacrylonitrile (PAN)-based solid polymer electrolyte. The usefulness of Li 4 Ti 5 O 12 was demonstrated for three distinctive applications: (i) cathode of a 1.5 V rechargeable Li battery, (ii) auxiliary electrode for investigating the electrochemistry of Li insertion cathode materials, and (iii) anode of a Li-ion cell in conjunction with a high voltage cathode, e.g., cubic spinel LiMn 2 O 4 . The micron-sized Li 4 Ti 5 O 12 exhibited a capacity of 160 mAh/g at C/20-C/30 rates which is about 7% better than the capacity exhibited by this material prepared according to a previously published procedure. More importantly, the micron-sized oxide showed significantly better high rate capability, yielding 25-50% larger capacity at the 3C to 8C rates. Li/solid polymer electrolyte//Li 4 Ti 5 O 12 cells underwent extended, ull-depth, charge/discharge cycling at≥1C rates with virtually no capacity fade. The auxiliary electrode concept was demonstrated in Li (4+x) Ti 5 O 12 (x∼ 1.2)//solid polymer electrolyte//LiMn 2 O 4 cells. At a 1C discharge rate, more than 150 cycles were demonstrate in these cells with a capacity fade rate of about 0.1% per cycle and an end utilization of ∼90 mAh/g for spinel LiMn 2 O 4 . Balanced Li 4 Ti 5 O 12 //solid polymer electrolyte//LiMn 2 O 4 cells of slightly cathode-limited configuration showed full-depth extended cycling capability at a utilization of ∼90 mAh/g for LiMn 2 O 4 at 1C rate and a capacity fade rate of about 0.08% per cycle. The capacity fade in the LiMn 2 O 4 -containing cells appears to come from this cathode. When fully packaged, specific energy of the Li//PAN electrolyte//Li 4 Ti 5 O 12 cell would be about 57 Wh/kg and that of the Li 4 Ti 5 O 12 //PAN electrolyte//LiMn 2 O 4 cell is about 60 Wh/kg.

Abstract: A planar fuel cell (20) is provided, including a membrane electrode assembly (23) sandwiched between two current collector assemblies (21, 22). The membrane electrode assembly is a single sheet of a polymer electrolyte membrane with an array of anodes (27) on one side and an array of corresponding cathodes (28) on the other side. The current collectors (25) can be supported by a plastic frame (24), and they have an interconnect tab (26) that provides an electrical pathway to the exterior of the membrane electrode assembly. The interconnect tab is situated to provide electron transfer between the anodes and the cathodes such that the interconnect tab does not traverse the thickness of the polymer electrolyte membrane. When the planar fuel cell is assembled, the interconnect tab is sealed to prevent leaking of fuel or oxidant gases. Fuel is distributed (36) to only one side of the membrane electrode assembly and oxidant is distributed (36) only to the other side.

Abstract: A fuel cell gas management system (10) including a cathode humidification system (30) for transferring latent and sensible heat from an exhaust stream (16) to the cathode inlet stream (14) of the fuel cell (26); and anode humidity retention system (80) for maintaining the total enthalpy of the anode stream (20) exiting the fuel cell equal to the total enthalpy of the anode inlet stream (18); and a cooling water management system (130) having segregated deionized water and cooling water loops interconnected by means of a brazed plate heat exchanger.

Abstract: To improve the anodic stability of ambient temperature electrolytes, a nontoxic solvent based on the sulfone polar group has been synthesized and evaluated i the presence of high potential cathode materials. Solutions of high stability salts such as LiClO{sub 4} and Li made in this solvent, withstand 5.8 V vs. Li{sup +}/Li before onset of oxidation, defined by a stringent criterion, even in the presence of high surface area electrodes such as activated charcoal on Pt. Reversible Li deposition and stripping is observed at negative potentials. This means not only that a wide range of overcharge protection is available for high voltage cathodes in current use, but also that exotic cathodes accepting electrons up to 5.5 V from Li{sup +}/Li may now be incorporated in rechargeable lithium cells.