Papers by Keyword: Hydrogen Storage Alloy

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Authors: Jing Yi Chang, Yean Der Kuan, Yun Siang Weng, Sheng Ching Chan
Abstract: This study developed a heating mechanism applicable to hydrogen storage tank, in order to enhance the stability and durability of proton exchange membrane fuel cell (PEMFC). This study discussed two heating modes. The first mode was using heating wire to wind the hydrogen storage tank body. Heating wires were used to wind the upper, middle and lower parts of the hydrogen storage tank and the whole tank respectively for discussion. The second heating mode was to use the PEMFC cathode waste heat to heat the hydrogen storage tank body. This study discussed the variations of hydrogen release rate and tank body temperature with the hydrogen release time in different heating mechanisms. The research results can serve as reference for system design in various applications.
Authors: Yu Fang Lin, Dongliang Zhao, Xin Lin Wang
Abstract: Employing the first principles discrete variational method(DVM), we investigated the electronic structure of LaNi5 hydrogen storage alloys containing various alloying elements, M=Mn,Fe,Co. The results showed that s electrons of H mainly interact with s electrons of hydride-non-forming element Ni, though hydride forming element La have stronger affinity to hydrogen atom. And alloying elements strengthened the bond between B-H, so decreased the capacity of doped-system.
Authors: Diogo M.F. Santos, Yun Chen, César A.C. Sequeira
Abstract: Anodic polarisation curves of Mm(Ni3.6Co0.7Mn0.4Al0.3)x (Mm = mischmetal, 0.85  x  1.15) electrodes were measured under the conditions of various initial concentrations of absorbed hydrogen (H/M), potential sweeping rates (v), temperatures (T), and amounts of reducing agent (y = [NaBH4]) in alkaline solution. Anodic peak current (Ip) at the Mm(B5)x electrodes increased with an increase in T, x and y values. In addition, the Ip value depended linearly on initial hydrogen concentration and square root of potential sweeping rate, irrespective of T, x and y values. Furthermore, the activation energy for hydrogen diffusion decreased with an increase in x and y values. From these results, it is considered that the surface reduction treatment of the Mm(B5)x alloys, performed in alkaline solution with sodium borohydride, the nonstoichiometry and the initial concentration of absorbed hydrogen, are important factors for improving the charge-discharge performance of negative electrodes for metal-hydrogen energy systems.
Authors: Akihiro Nakai, Masayuki Mizumoto, Akio Kagawa
Abstract: A power actuator based on a great volume expansion on hydrogenation of hydrogen storage alloys (HSAs) has been developed. The actuator has a bimorph structure consisting of Pd-Ni alloy and Cu-plating to convert the volume change into bending motion. The techniques to control the bending and rotation motions of the actuator were investigated by adjusting alloy composition, shape and the amount of hydrogen absorbed in the HSA. It is found that Pd-Ni alloy actuators exhibit a cyclic bending motion on hydrogen absorption and desorption cycles and the bending behavior can be controlled by controlling the hydrogen pressure. When a ribbon shaped actuator was deformed into the “L” shape on the transverse section, a rotation motion was observed without modifying the basic bimorph structure of the actuator.
Authors: Yan Jun Wang, Tatsuhiko Aizawa, Chikashi Nishimura
Authors: Atsushi Mitsuo, Tatsuhiko Aizawa
Authors: An Qiang Deng, Jing Bo Fan, Ke Nong Qian
Abstract: La0.8-xPrxMg0.2Ni3.8 (x=0,0.15,0.3,0.4) alloys were prepared by induction melting followed by annealing treatment at 1173K for 24 h. Alloys structure and electrochemical properties of different Pr elecment have been studied systematically by X-ray diffraction(XRD) with the Rietveld methold , scanning electron microscope (SEM)and electrochemical experiments. Alloys structure analyses show that all of the alloys mainly consisted of complex phases such as (La,Pr,Mg)5Ni19 phase(Ce5Co19-type,SG:R-3m), (La,Pr,Mg)5Ni19 phase (Pr5Co19-type, SG:P63/mmc)and (La,Pr)Ni5 phase(CaCu5-type,SG:P6/mmm), Pr eletment was benefited to the formation of Pr5Co19-type phase, The (La,Pr,Mg)5Ni19 phase not only exists in high temperature area but also exists in low temperature area.The activation characteristic and maximum discharge capacity got worse with increasing Pr content,At the same time, The Pr5Co19–type phase and Ce5Co19–type phase all had better electrochemical cyclic stability than the PuNi3-type phase in earth–Mg–Ni-based Hydrogen Storage Alloys.The cyclic stability of alloy electrodes was a closely related to the stacking structures consisting of one Laves-type slab (AB2) and three CaCu5-type slabs (AB5) along the c-axis.
Authors: Yu Zhou, Xian Yun Peng, Li Qiang Ji, Yan Ping Fan
Abstract: Microstructuresand electrochemical properties of La0.73Ce0.27Ni3.25+xMn0.35Al0.15Cu0.75Fe0.25 alloys are investigated. XRD results indicate that all alloys are identified with LaNi5 phase with CaCu5 type hexagonal structure, and lattice parameter a, c and cell volume V decrease with increasing x value. Maximum discharge capacity first increases from 286.4 mAh/g (x = 0) to 313.2 mAh/g (x = 0.25), and then decreases to 308.9 mAh/g (x = 0.75). High-rate dischargeability of the alloy electrodes increases when x increases from 0 to 0.75. HRD1200 increases with the increase in the I0 and D, and shows a linear relationship with the I0 and D.
Authors: Hideaki Tanaka, Song Han, Qiang Xu, Nobuhiro Kuriyama, K. Aihara, Naoki Taoka
Abstract: Ti-Cr-V alloys with body-centered cubic (BCC) structure were investigated on hydrogen absorbing-desorbing cyclic durability by using H2 without and with several concentrations of CO (Hereafter, they are described as pure H2 and n ppm CO, respectively.). The alloy which offers the excellent durability except the early stages of cyclic absorption-desorption under pure H2 atmosphere gave good durability also in a flow of low concentration of CO. However, capacities’ degradation curves under high CO concentration reflected that duration and concentration effects competed with each other. The results suggests to be able to express each degradation by intrinsic and extrinsic factors as an aggregation of several prime functions.
Authors: Zhong Feng Guo, Jun Hong Hu, Liang Xu, Chun Ming Xia
Abstract: In order to analysis the properties of hydrogen storage alloy, hydrogen storage properties, the test principle of pressure-composition-temperature (PCT) was analyzed in detailed, the new type PCT test system was designed on the base of the state equation of ideal gas. The PCT test system is composed of five parts: air supply system, vacuum system, response system, data acquisition system and electric control system. The PCT test system can be carried out in four channel linkage experiments. The hydrogen storage performance experiments of LaNi5 hydrogen storage alloy were carried out by using this system. Hydrogen absorption curve was gained by two kinds of modeling methods. Results show that: the test system can test the hydrogen absorption curve smoothly, efficiently and accurately. The design of this system is reasonable and the test result is reliable.
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