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Journal of Rare Earths 2009年第2期27卷 244-249页

作者：闫慧忠孔繁清熊玮李宝犬李金 Ruike National Engineering Research Center of RE Metallurgy & Functional Materials Baotou 014030China Baotou Research Institute of Rare Earth Baotou 014030China

In order to investigate the effect of substituting La with Pr on structural and hydrogen storage properties of La-Mg-Ni system （AB3.5-type） hydrogen storage alloys, a series of La0.65-xPrxNd0.12Mg0.23Ni3.4Al0.1（x=0, 0.10, 0.15, 0.2） hydrogen storage alloys were prepared. X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy dispersive spectrometer （EDS） analyses revealed that two alloys （x=0.0 and 0.10） were composed of （La,Mg）2（Ni,Al）7 phase, La（Ni,A1）5 phase and （La,Mg）Ni2 phase, while other alloys （x=0.15 and 0.20） consisted of （La,Mg）2（Ni,A1）7 phase, La（Ni,A1）5 phase, （La,Mg）Ni2 phase and （La,Mg）（Ni,A1）3 phase. All alloys showed, however, only one pressure plateau in P-C isotherms. The Pr/La ratio in alloy composition influenced hydrogen storage capacity and kinetics properties. Electrochemical studies showed that the discharge capacity decreased from 360 mAh/g （x=-0.00） to 335 mAh/g （x=-0.20） as x increased. But the high-rate dischargeability （HRD） of alloy electrodes increased from 26% （x=0.00） to 56% （x=-0.20） at a discharge current density of Id=1800 mA/g. Anode polarization measurements were done to further understand the electrochemical kinetics properties after Pr substitution.

关键词： hydrogen storage alloy La-Mg-Ni system metal hydrides MH/Ni batteries electrochemical properties rare earths

Phase structure and hydrogen storage properties of REMg8.35Ni2.18Al0.21 （RE=La, Ce, Pr, and Nd） hydrogen storage alloys

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Journal of Rare Earths 2013年第8期31卷 784-789页

作者： LIU Yanqing HAN Shumin HU Lin LIU Baozhong ZHAO Xin JIA Yanhong College of Environmental and Chemical Engineering Yanshan University Qinhuangdao 066004 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 China School of Materials Science and Engineering Henan Polytechnic University Jiaozuo 454000 China

REMg8.35Ni2.18Al0.21 （RE=La, Ce, Pr, and Nd） alloys were prepared by induction melting and following annealing. X-ray diffraction （XRD） and scanning electron microscopy （SEM） results showed that the alloys were composed of Mg2Ni, （La, Pr, Nd）MgzNi, （La, Ce）2MgxT, （Ce, Pr, Nd）Mg12 and Ce2Ni7 phases. The above phases were disproportioned into Mg2NiH4, MgH2 and REHx （x=2.5 1 or 3） phases in hydriding. CEH2.51 phase transformed into CEH2.29 phase in dehydriding, whereas LaH3, PrH3 and NdH3 phases re- mained unchanged. The PrMg8.41Ni2.14Al0.20 alloy had the fastest hydriding kinetics and the highest dehydriding plateau pressure while the CeMg8.35Ni2.18Al0.21 alloy presented the best hydriding/dehydriding reversibility. The onset hydrogen desorption tempera- ture of the CeMg8.35Ni2.18Al0.21 hydride decreased remarkably owing to the phase transformation between the Cell2.51 and the CEH2.29.

关键词： rare earth hydrogen storage alloy Mg-based alloys phase structure hydriding kinetics

Microstructure and electrochemical characteristics of La_(0.7)Ce_(0.3)Ni_(3.75)Mn_(0.35)Al_(0.15)Cu_(0.75-x)(V_(0.81)Fe_(0.19))_x hydrogen storage alloys

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Journal of Rare Earths 2012年第8期30卷 769-774页

作者：刘宝忠胡梦娟李安铭吉力强张宝庆朱惜林 School of Materials Science&Engineering Henan Polytechnic University Inner Mongolia Rare Earth Ovonic Metal Hydride Co.Ltd.

Microstructure and electrochemical characteristics of La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-x（V0.81Fe0.19）x hydrogen storage alloys were investigated. XRD indicated that La0.7Ce0.3Ni3.75Mn0.35Al0.15Cu0.75-x（V0.81Fe0.19）x alloys consisted of a single phase with CaCus-type structure, and the lattice parameter a and cell volume V increased with increasing x value. The maximum discharge capacity first increased from 319.0 （x=0） to 324.0 mAh/g （x=0.05）, and then decreased to 307.0 mAh/g （x=0.20）. The high-rate dischargeability at the discharge current density of 1200 mA/g first increased from 52.1% （x=0） to 59.1% （x=0.15）, and then decreased to 55.4% （x=0.20）. The hydrogen diffusion in the bulky alloy was responsible for the high-rate dischargeability. Cycling stability first increased with increasing x from 0 to 0.10 and then de- creased when x increased to 0.20, which was resulted fi＇om the synthesized effect of the improvement of the pulverization resistance and the decrease of corrosion resistance.

关键词： hydrogen storage alloy VFe alloy phase structure electrochemical property Ni/MH batteries rare earths

Electrode properties and phase composition of Ti_(0.5)Ni_(0.25)Al_(0.25) hydrogen storage alloys and theoretical simulation

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Transactions of Nonferrous Metals Society of China 2010年第10期20卷 1899-1905页

作者：吴军徐艳辉陈长聘郑军伟李德成 Institute of Electrochemical Power Sources Soochow University Department of Materials Science and Engineering Zhejiang University

Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was *** phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various *** reaction kinetic parameters were also studied with proper electrochemical *** influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical *** results show that,proper ball-milling with nickel powders is beneficial to electrochemical *** theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.

关键词： hydrogen storage alloy electrochemical kinetics metal hydride electrode theoretical simulation

Structure and high-temperature electrochemical properties of La_(0.60)Nd_(0.15)Mg_(0.25)Ni_(3.3)Si_(0.10) hydrogen storage alloys

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Journal of Rare Earths 2011年第6期29卷 574-579页

作者：郭佩佩林玉芳赵海花郭世海赵栋梁 Central Iron & Steel Research Institute

The structure and high-temperature electrochemical properties of the as-cast and annealed （940 °C, 8 h） La0.60Nd0.15Mg0.25Ni3.3Si0.10 hydrogen storage alloys were investigated. The X-ray diffraction revealed that the multiphase structure of the as-cast alloy with LaNi5 phase as the main phase was converted into a double-phase structure with La2Ni7 phase as the main phase after annealing. The surface morphology studied by scanning electronic microscope （SEM） showed that the annealed alloy had a much higher anti-corrosion ability than the as-cast alloy. Both alloys presented excellent activation characteristics at all test temperatures. The maximum discharge capacity of the as-cast alloy decreased when the test temperature increased, while the temperature almost had no effect on the annealed alloy. As the test temperature increased, the cyclic stability and charge retention of both alloys decreased, and these properties were improved significantly by annealing.

关键词： hydrogen storage alloy annealing structure high-temperature electrochemical properties rare earths

Study on High Rate Discharge Performance and Mechanism of AB_5 Type hydrogen storage alloys

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Journal of Rare Earths 2004年第4期22卷 509-513页

作者：郭靖洪陈德敏于军张建海刘国忠杨柯 Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China Suppo Battery Co. Ltd. Shenyang 110015 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110015 China Suppo Battery Co. Ltd. Shenyang 110015 China

The effects of surface treatment, particle size distribution,rare earth composition and B additive on the high rate discharge performance of hydrogen storage alloys were investigated. It is found that the activity, discharge capacity and high rate dischargeability of the alloys are improved after physical and chemical modification as a result of the increase of the surface area and formation of the electrocatalysis layers, which increase both the electrochemical reaction rate on the alloy surface and H diffusion rate in the alloy bulk. It is also found that both the over-coarse and over-fine particle size increase the contact resistance of the electrode, resulting in a decrease of discharge capacity, deterioration of high rate dischargeability and lower discharge plateau. In another word, a suitable particle size distribution can enhance the alloy activity, discharge capacity and high rate dischargeability. In addition, the high rate dischargeability is enhanced by increasing La content and decreasing Ce content of the alloy composition because of enlargement of the unit cell volume and the improvement of the surface activity. Moreover, B additive resultes in the formation of the second phase, and makes the alloys easier pulverization, which greatly improves the activity, discharge capacity and high rate dischargeability.

关键词： storage energy technology hydrogen storage alloy discharge capacity activity high rate dischargeability rare earths

Effect of Heat-Treatment Process on Properties of Rare Earth Mg-Based System hydrogen storage alloys with AB_3-Type

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Journal of Rare Earths 2006年第z2期24卷 340-342页

作者：王英卢其云彭能肖方明唐仁衡 Research Institute of Rare Metal Guangzhou Research Institute of Non-Ferrous Metals

The effect of heat-treatment process on the properties of Mm0.8Mg0.2(NiCoAlMn)3.5 hydrogen storage alloy was discussed . The electrochemical properties such as cycling stability, activation property, and the plateau voltage of the alloy which was heat-treated in various temperatures and times had different changes during the cycle process, the optimum heat-treatment conditions of this alloy were determined by this work.

关键词： heat-treatment rare earth Mg-based system hydrogen storage alloy Ni/MH battery

Influence of magnesium content on structure and electrochemical properties of La_(1-x)Mg_xNi_(1.75)Co_(2.05) hydrogen storage alloys

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Journal of Rare Earths 2016年第12期34卷 1235-1240页

作者：蔡鑫魏范松胥小丽张玉 School of Materials Science and Engineering Jiangsu University of Science and Technology

La（1-x）MgxNi（1.75）Co（2.05）（x=0.07, 0.08, 0.10, 0.13, 0.15） alloys were prepared by high-frequency inductive method, and then their structure and electrochemical properties were investigated systematically. The XRD analysis revealed that the alloys consisted of LaNi5 phase and La4MgNi（19）（Ce5Co（19）＋ Pr5Co（19）） phase, and the introduction of Mg could promote the formation of La4MgNi（19） phase. The observation of microstructure showed that all the alloys processed dendritic structure, which was refined with the increase of x value. The electrochemical measurements showed that all the alloys could be activated within 2 cycles, and with increasing x, the maximum discharge capacity obviously increased from 254.00 m Ah/g（x=0.07） to 351.51 mAh/g（x=0.15）, but the cycling stability（S（80）） decreased somehow from 78.4% to 73.9%. Meanwhile, the appropriate addition of Mg could improve the high-rate discharge capacity（HRD） of the alloy electrodes, which was mainly controlled by the electrochemical reaction rate on the surface of the alloys.

关键词： A5B19-type hydrogen storage alloy phase structure electrochemical properties rare earths

Composition optimization and electrochemical characteristics of Co-free Fe-containing AB_5-type hydrogen storage alloys through uniform design

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Journal of Rare Earths 2012年第4期30卷 361-366页

作者：晁栋梁陈云贵朱昌荣吴朝玲朱丁 College of Materials Science and Engineering Sichuan University

In order to reduce the cost of ABs-type hydrogen storage alloys, effects of substitution of Ce for La （A side） and Fe, Mn, Al for Ni （B side） on structural and electrochemical properties of （LaCe）;（NiFeMnAl）s alloys were studied systematically. To make component uniform and operation easy, uniform design （UD） method was introduced into the study of composition optimization of Co-free Fe-containing ABs-type alloys for the first time. X-ray diffraction （XRD） results showed that the designed alloys were of single CaCus-type structure phase. The replacement of Fe had a severe effect on electrochemical capacity, and the substitution of Fe and A1 had a synergetic action among the unit cell volume, cycling stability and high rate discharge property. Interestingly, it was found that the hydrogen storage alloys with excessively high plateau pressure showed a tilted line in Nyquist plot instead of the semicircle, and the current decayed rapidly to near zero at the beginning of the step in constant potential step （CPS）, indicating that electrochemical impedance spectra （EIS） and CPS cannot accurately measure the electrochemical kinetics process of the hydrogen storage alloys with excessively high plateau pressure.

关键词： hydrogen storage alloy Co-free Fe-containing composition optimization electrochemical characteristics uniform design rare earths

Effect of Rare Earth Elements on Structure and Electrochemical Properties of PuNi_3-type hydrogen storage alloys

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Journal of Rare Earths 2005年第S1期23卷 343-349页

作者：张法亮罗永春阎汝煦陈剑虹 Department of Materials Science and Engineering Lanzhou University of Technology Lanzhou 730050 Key Laboratory of advanced Nonferrous Metal Materials Lanzhou University of Technology Lanzhou 730050

Structure and electrochemical properties of (La, Ce, Pr, Nd)_2MgNi_9 hydrogen storage alloys were investigated through orthogonal design experiments, and the alloys were obtained through induction melting followed by annealing treatment. The structure of main phase in alloys belongs to PuNi_3-type with a space group R3m. Rare earth elements, as a substitute of lanthanum, have a significant effect on phase structure of alloys, elements of cerium and neodymium are beneficial to the formation of Gd_2Co_7-type phase with a space group P 6_3/mmc. Rare earth elements can decrease the unit cell volume of main phase of alloys dramatically, and increase the axis ratio. The results of electrochemical experiment showed that the discharge capacity of alloy electrodes ranged from 342.97 to 380.68 mAh·g -1, and elements of cerium and neodymium can reduce the discharge capacity of alloy electrodes significantly. Compared to the electrode of La_2MgNi_9 alloy, the substitution of lanthanum by rare earth elements did not improve the cyclic stability of alloy electrodes due to the anisotropic structure change of unit cell. While rare-earth elements can improve the high rate dischargeability of alloy electrodes, the high rate dischargeability of alloy electrodes could reach the maximum when the unit cell volume of PuNi_3-type structure was about 0532 nm.

关键词： hydrogen storage alloy PuNi_3-type crystal structure electrochemical properties orthogonal experiment design