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In this dissertation, partial element substitution was used to improve the hydrogen storage properties and electrochemical cycle stability of AB3 type alloys. In addition composite method was proposed to enhance the cycle durability of AB3 type alloys. Meanwhile a critical review on the working principles, advantages and drawbacks, limitations of six categories of techniques commonly applied on the characterization of hydrogen storage materials was presented. These techniques include the Sieverts technique, gravimetry, secondary ion mass spectrometry, thermal desorption spectroscopy, neutron scattering and electrochemical technique.The microstructure and hydrogen storage properties of cost-competitive La0.51-xY0.05+xCa1.03Mg1.32Ni9 (x=0, 0.15, 0.35) alloys were investigated. The change of Y content would alter the microstructure of La-Y-Ca-Mg-Ni alloy such as phase abundance, lattice parameters and cell volume. The Y abundant sample exhibited a higher absorption plateau pressure, lower hydrogen capacity and relatively inferior hydrogen absorption kinetics. In addition the hydride stability was reduced with the increase of Y content. The electrochemical properties of La0.51-xY0.05+xCa1.03Mg1.32Ni9 (x=0, 0.15, 0.35) alloy powder were systematically investigated. The increase of Y content in sample alloy would result in an improvement of cycle stability, suppression of particle pulverization, reduction of formation of corrosion products and elevation of rate capability at higher discharge rate. However excessive Y in the alloy would lead to a decrease in maximum capacity. Overall the electrodes made by La0.42Y0.22Ca0.78Mg1.01Ni9 alloy exhibited the best performance; the cycle stability was improved without significant loss in maximum capacity. The electrochemical performances of composite electrode composed of La0.51Y0.05Ca1.03Mg1.32Ni9 and x wt% La0.63Nd0.08Pr0.02Ce0.27(Al0.02Co0.14Mn0.06Ni0.78)5 (x =10, 30, 50) have also been studied. The electrode with 30 wt% AB5 el

The mechanism of cancer cell death induced by hydrogen discharged from Pd-5at.% Ni hydrogen storage alloy has been investigated. Cancer cell (HeLa: cervical cancer cell) death was observed in the limited region within ~ 3 mm from the sample. The measurement of surviving fraction of cells revealed that almost all the cancer cells in the well of 96-well multi plate, 6.2 mm in diameter were extinct (p < 0.01), while no detectable influence was observed in the normal cells. From the fluorescent imaging experiment, it was indicated that the cell death induced by discharged hydrogen was due to the "Apoptosis" and hydrogen peroxide was detected in both intracellular and extracellular regions. Furthermore, the generation of hydrogen radical and hydroxyl radical was observed in the ESR measurement. From the results obtained, the mechanism of cancer cell death is proposed., 2013 International Conference on Materials Science and Chemical Engineering, MSCE 2013; ; 20 February 2013 ～ 21 February 2013, Advanced Materials Research, 699, pp.284-290; 2013

A selective cancer cell death induced by discharged hydrogen from Pd-Ni base hydrogen storage alloy (HSA) powder is demonstrated. From the cell experiment and the measurement of surviving cell rate, it was found that cell death was seen only in cancer cells (HeLa: cervical cancer cell) after 24h- and 48h-immersion of Pd-5at.%Ni alloy powder, while no harmful influence was observed in normal cells (MDCK: renal epithelial cell). The range of cancer cell death was limited just near the HSA powder. It is suggested that the hydrogen radical emitted from the HSA powder induces the formation of hydrogen peroxide and brings a detrimental effect in the cancer cell, while hydrogen peroxide is decomposed by the enzyme, catalase, in normal cells, resulting in the selective death of cancer cells., 2013 International Conference on Materials Science and Chemical Engineering, MSCE 2013; ; 20 February 2013 ～ 21 February 2013, Advanced Materials Research, 699, pp.273-278; 2013

[EN] The microstructure and electrochemical properties of a La0.7Mg0.3Al0.3Mn0.4Co0.5Ni3.8 hydrogen storage alloy have been studied. The anode was prepared using a mixture of the ingot alloy in the as-cast state with carbon black and polytetrafiuoroethylene (PTFE) as a binder. A Ni(OH)(2) electrode was used as the cathode of the square-type test cell. A separator was used together with a 6M KOH electrolyte. Microstructure and phase composition of the alloy have been investigated using inductively coupled plasma atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). A niobium-containing alloy has also been included for a comparison.

[EN] The microstructure and electrochemical properties of a La0.7Mg0.3Al0.3Mn0.4Co0.5Ni3.8 hydrogen storage alloy have been studied. The anode was prepared using a mixture of the ingot alloy in the as-cast state with carbon black and polytetrafiuoroethylene (PTFE) as a binder. A Ni(OH)(2) electrode was used as the cathode of the square-type test cell. A separator was used together with a 6M KOH electrolyte. Microstructure and phase composition of the alloy have been investigated using inductively coupled plasma atomic emission spectrometry (ICP-AES), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction analysis (XRD). A niobium-containing alloy has also been included for a comparison.

Lab-size rechargeable metal hydride-air (MH-air) cells with a gas management device were designed in order to minimize the loss of electrolyte. An AB(5)-type hydrogen storage alloy was used as anode materials of the MH-air. The thickness of the metal hydride electrodes was in the range of 3.0-3.4 mm. Porous carbon-based air electrodes with Ag2O catalysts were used as bi-functional electrodes for oxygen reduction and generation. The electrodes were first examined in half-cells to evaluate their performance and then assembled into one MH-air cell. The results showed the good cycling stability of the rechargeable MH-air cell with a capacity of 1990 mAh. The discharge voltage was 0.69 V at 0.05-0.1 C. The charge efficiency was about 90%. The specific and volumetric energy densities were about 95 Wh kg(-1) and 140 Wh L-1, respectively., authorCount :2

This paper describes self-ignition combustion synthesis (SICS) of LaNi5 in a pressurized hydrogen atmosphere using metallic calcium as both the reducing agent and the heat source. In this study, the effects of hydrogen on the ignition temperature and the hydrogenation properties of the products were mainly examined. In the experiments, La2O3, Ni, and Ca were dry-mixed in the molar ratio of 1:10:6 and then heated up at a hydrogen pressure of 1.0 MPa until the ignition due to the hydrogenation of calcium. For the sake of comparison, the same experiments were performed in a normal argon atmosphere. The results showed that the ignition temperature was drastically lowered by hydrogen; it was only 600 K in the case of hydrogen as compared to 1.100K in the case of argon. The products also exhibited high initial activity and hydrogen storage capacity of 1.54 mass%. The proposed method offers many benefits for using cost-effective rare-earth oxide, saving productive time and energy, improving initial activity of the product and applying to any AB(5)-type hydrogen storage alloy. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

This paper describes self-ignition combustion synthesis (SICS) of LaNi5 in a pressurized hydrogen atmosphere using metallic calcium as both the reducing agent and the heat source. In this study, the effects of hydrogen on the ignition temperature and the hydrogenation properties of the products were mainly examined. In the experiments, La2O3, Ni, and Ca were dry-mixed in the molar ratio of 1:10:6 and then heated up at a hydrogen pressure of 1.0 MPa until the ignition due to the hydrogenation of calcium. For the sake of comparison, the same experiments were performed in a normal argon atmosphere. The results showed that the ignition temperature was drastically lowered by hydrogen; it was only 600 K in the case of hydrogen as compared to 1.100K in the case of argon. The products also exhibited high initial activity and hydrogen storage capacity of 1.54 mass%. The proposed method offers many benefits for using cost-effective rare-earth oxide, saving productive time and energy, improving initial activity of the product and applying to any AB(5)-type hydrogen storage alloy. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

The paper describes the self-ignition combustion synthesis (SICS) of the hydrogen storage alloy TiFe_[1-x]Mn_[x] (X = 0, 0.1, 0.2, 0.3, and 0.5) in a hydrogen atmosphere, where the hydrogenation properties of the products are mainly examined. in the experiments, the well-mixed powders of Ti, Fe, and Mn in the molar ratio of 1:1-X:X were uniformly heated up to 1473 K, and then were cooled naturally in pressurized hydrogen at 0.9 MPa. All products were successfully synthesized by utilizing the exothermic reaction, which occurred at around 1358 K. The XRD analysis showed that SICS generated TiFe_[1-x]Mn_[x] in the range of X value from 0 to 0.3. All SICSed products absorbed hydrogen smoothly at 298 K at an initial pressure of 4.1 MPa. Most significantly, TiFe0.8Mn0.2 improved the dual plateau property. The results revealed that SICS was quite effective for producing the hydrogen storage alloy TiFe_[1-x]Mn_[x].

The paper describes the self-ignition combustion synthesis (SICS) of the hydrogen storage alloy TiFe_[1-x]Mn_[x] (X = 0, 0.1, 0.2, 0.3, and 0.5) in a hydrogen atmosphere, where the hydrogenation properties of the products are mainly examined. in the experiments, the well-mixed powders of Ti, Fe, and Mn in the molar ratio of 1:1-X:X were uniformly heated up to 1473 K, and then were cooled naturally in pressurized hydrogen at 0.9 MPa. All products were successfully synthesized by utilizing the exothermic reaction, which occurred at around 1358 K. The XRD analysis showed that SICS generated TiFe_[1-x]Mn_[x] in the range of X value from 0 to 0.3. All SICSed products absorbed hydrogen smoothly at 298 K at an initial pressure of 4.1 MPa. Most significantly, TiFe0.8Mn0.2 improved the dual plateau property. The results revealed that SICS was quite effective for producing the hydrogen storage alloy TiFe_[1-x]Mn_[x].

The paper describes the self-ignition combustion synthesis (SICS) of the hydrogen storage alloy TiFe_[1-x]Mn_[x] (X = 0, 0.1, 0.2, 0.3, and 0.5) in a hydrogen atmosphere, where the hydrogenation properties of the products are mainly examined. in the experiments, the well-mixed powders of Ti, Fe, and Mn in the molar ratio of 1:1-X:X were uniformly heated up to 1473 K, and then were cooled naturally in pressurized hydrogen at 0.9 MPa. All products were successfully synthesized by utilizing the exothermic reaction, which occurred at around 1358 K. The XRD analysis showed that SICS generated TiFe_[1-x]Mn_[x] in the range of X value from 0 to 0.3. All SICSed products absorbed hydrogen smoothly at 298 K at an initial pressure of 4.1 MPa. Most significantly, TiFe0.8Mn0.2 improved the dual plateau property. The results revealed that SICS was quite effective for producing the hydrogen storage alloy TiFe_[1-x]Mn_[x].

The paper describes the self-ignition combustion synthesis (SICS) of the hydrogen storage alloy TiFe_[1-x]Mn_[x] (X = 0, 0.1, 0.2, 0.3, and 0.5) in a hydrogen atmosphere, where the hydrogenation properties of the products are mainly examined. in the experiments, the well-mixed powders of Ti, Fe, and Mn in the molar ratio of 1:1-X:X were uniformly heated up to 1473 K, and then were cooled naturally in pressurized hydrogen at 0.9 MPa. All products were successfully synthesized by utilizing the exothermic reaction, which occurred at around 1358 K. The XRD analysis showed that SICS generated TiFe_[1-x]Mn_[x] in the range of X value from 0 to 0.3. All SICSed products absorbed hydrogen smoothly at 298 K at an initial pressure of 4.1 MPa. Most significantly, TiFe0.8Mn0.2 improved the dual plateau property. The results revealed that SICS was quite effective for producing the hydrogen storage alloy TiFe_[1-x]Mn_[x].

TiCr2 with a body-centered-cubic (BCC) structure was synthesized successfully by mechanical alloying (MA) of elemental powders and mechanical grinding (MG) of as-cast ingots. The formation mechanisms of the TiCr2 were investigated using X-ray diffraction (XRD) analysis. The thermal stability and hydrogen ab/desorption kinetics were studied using a differential scanning calorimetry (DSC) and a volumetric method. The results showed that the formation mechanisms of TiCr2 in mechanical alloying and mechanical grinding were different. Mechanical alloying is superior to mechanical grinding in processing TiCr2 alloy for hydrogen storage. D 2003 Elsevier B.V. All rights reserved.

The Nickel Metal Hydride (NiMH) battery has an active gas phase during operation. This is due in part to the aqueous electrolyte causing oxygen evolution on the positive nickel electrode, and in part due to the hydrogen stored in the negative metal hydride (MH) electrode being in equilibrium with gaseous hydrogen. The gas phase reactions are closely connected to the battery function and must therefore be accounted for when creating a successful battery management system (BMS). This study explores a pressure model for management of the NiMH battery. By using measured current, voltage, and temperature as input, the total pressure and gas composition can be modeled. Model parameters are fitted by comparing the modeled total pressure to the measured pressure. By using the system voltage signal, the difficulty of simultaneously modeling the voltage based on the current is circumvented. A model like this opens the way to new ways of battery system management through use of calculated partial pressures and deviations from the modeled total pressure. This can help increasing safety and longevity of battery systems., QC 20231030