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| 1 | Electrochemical performances of as-cast and annealed La_(0.8-x)Nd_xMg_(0.2)Ni_(3.35)Al_(0.1)Si_0.05(x=0-0.4) alloys applied to Ni/metal hydride (MH) battery显示文摘The La-Mg-Ni-based A2B7-type La0.8-xNdxMg0.2Ni3.35 Al0.1Si0.05(x=0,0.1,0.2,0.3,and0.4) electrode alloys were prepared by casting and annealing. The influence of the partial substitution of Nd for La on the structure and electrochemical performances of the alloys was investigated. The structural analysis of X-ray diffraction and scanning electron microscopy reveals that the experimental alloys consist of two major phases: (La,Mg)2Ni7 with the hexagonal Ce2Ni7-type structure and LaNi5 with the hexagonal CaCu 5-type structure as well as some residual phases of LaNi3 and NdNi5 . The electrochemical measurements indicate that an evident change of the electrochemical performance of the alloys is associated with the substitution of Nd for La. The discharge capacity of the alloy first increases then decreases with the growing Nd content, whereas their cycle stability clearly grows all the time. Furthermore, the measurements of the high rate discharge ability, the limiting current density, and hydrogen diffusion coefficient all demonstrate that the electrochemical kinetic properties of the alloy electrodes first augment then decline with the rising amount of Nd substitution. | Yang-Huan Zhang Hui-Ping Ren Tai Yang Chen Zhao Li-Cui Chen Hong-Wei Shang Dong-Liang Zhao | 2013 | Rare Metals2013，32，2： | 8 |
| 2 | Electrochemical hydrogen storage characteristics of La_(0.75-x) M_xMg_(0.25)Ni_(3.2)Co_(0.2)Al_(0.1)(M=Zr,Pr;x=0,0.1) alloys prepared by melt spinning显示文摘In order to ameliorate the electrochemical hydrogen storage performances of La-Mg-Ni system A_2B_7-type electrode alloys, the partial substitution of M (M = Zr, Pr) for La was performed. The melt spinning technology was used to fabricate the La_(0.75-x)M_xMg_0.25Ni_3.2Co_0.2Al_0.1 (M = Zr, Pr; x = 0, 0.1) electrode alloys. The influences of the melt spinning and substituting La with M (M = Zr, Pr) on the structures and the electrochemical hydrogen storage characteristics of the alloys were investigated. The analysis of XRD, SEM, and TEM reveals that the as-cast and spun alloys have a multiphase structure composed of two main phases (La, Mg)_2Ni_7 and LaNi_5 as well as a residual phase LaNi_2 . The as-spun (M = Pr) alloy displays an entire nanocrystalline structure, while an amorphous-like structure is detected in the as-spun (M = Zr) alloy, implying that the substitution of Zr for La facilitates the amorphous formation. The electrochemical measurements exhibit that the substitution of Pr for La clearly increases the discharge capacity of the alloys; however, the Zr substitution brings on an adverse impact. Meanwhile, the M (M = Zr, Pr) substitution significantly enhances its cycle stability. The melt spinning exerts an evident effect on the electrochemical performances of the alloys, whose discharge capacity and high rate discharge ability (HRD) first mount up and then fall with the growing spinning rate, whereas their cycle stabilities monotonously augment as the spinning | ZHANG Yanghuan YANG Tai CAI Ying HOU Zhonghui REN Huiping ZHAO Dongliang | 2012 | Rare Metals2012，31，5： | 7 |
| 3 | Microstructure of nano precursors of La-Mg hydrogen storage alloy synthesized by sol-gel technology at different pH values显示文摘Sol-gel technology was employed to synthesize nanosized precursors of La-Mg hydrogen storage alloy at different pH values (0.5,1.5,8.0 and 9.0) of reaction solution.The effect of pH value on microstructure of the nano precursors of La-Mg hydrogen storage alloy was studied by infrared radiation (IR),thermo-gravimetric and differential thermal analysis (TG/DTA),X-ray diffraction analyzer (XRD) and transmission electron microscopy (TEM).IR results indicate that the chelating agent,citric acid,is not fully ionized,and carboxyl groups are not entirely used to complex metal ions in acidic solutions.The efficiency of complexing metal ions is enhanced in basic solutions.TG/DTA results show that the combustion may take place with low rate of the flame propagation that causes the longer combustion time when pH<1.5.On the contrary,the dry gel synthesized in basic solution combusts at low ignition temperature and combustion reaction is violent; it is easy to form fine particles.XRD and TEM results reveal that the precursor powders are mainly two-phase mixture of La2O3 and MgO.The morphology of the particles is almost flake with the size of~30 nm when pH is 8.0. | WANG Dahui XIA Jihong ZHANG Sha | 2012 | Rare Metals2012，31，5： | 3 |
| 4 | Microstructure and Hydrogen Absorption/Desorption Behavior of Mg23-xLaxNi10 Alloy显示文摘Induction melting was used as a routine method to synthesize Mg_(23)Ni_(10), Mg_(22)LaNi_(10) and Mg_(21)La_2Ni_(10) alloys, and followed by a detailed microstructural characterization which included X-ray diffraction(XRD), scanning electron microscopy(SEM) with energy dispersive spectrometer(EDS), high resolution transmission electron microscope(HRTEM) and hydrogen absorption/desorption measurements. XRD analysis results showed that Mg_2Ni and Mg phases were detected in the XRD pattern of the Mg_(23)Ni_(10) alloy, however, the La addition results in conversion from Mg to LaMg_3 and La_2Mg_(17) phases and appearance of crystal defects included dislocations, twin grain boundary and vacancy in the Mg_(22)LaNi_(10) and Mg_(21)La_2Ni_(10) alloy textures. The total maximum hydrogen absorption capacity was 4.45 wt% for the Mg_(23)Ni_(10) alloy, however, the Mg_(22)LaNi_(10) and Mg_(21)La_2Ni_(10) alloys with vacancy, dislocations and twin grain boundary, absorbed 3.66 wt% and 3.60 wt%, respectively, indicating that the La addition led to decreasing of the maximum hydrogen absorption capacity. Besides, hydrogen absorption/desorption of 90% of saturated state expended for about 456 and 990 s for pristine Mg_(23)Ni_(10) alloy, by contrast, the time decreased owing to improvement of hydrogen absorption and desorption kinetics in the alloy with La element, with which the uptake time for hydrogen content to 90% of saturated state was 150 and 78 s, and 90% hydrogen can be released in 930 and 804 s for Mg_(22)LaNi_(10) and Mg_(21)La_2Ni_(10) alloys in the experimental condition. | 董小平 杨丽颖 PANG Yanrong WANG Tao WEN Lijuan | 2018 | Journal of Wuhan University of Technology(Materials Science)2018，33，2： | 0 |
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