Laves phase hydrogen storage alloys for super-high-pressure metal hydride hydrogen compressors

Ti-Cr- and Ti-Mn-based alloys were prepared to be low- and high-pressure stage metals for a double-stage super-high-pressure metal hydride hydrogen compressor. Their crystallographic characteristics and hydrogen storage properties were investigated. The alloy pair Ti_0.9Zr_0.1Mn_1.4-Cr_0.35V_0.2Fe_0.05/TiCr_1.55Mn_0.2Fe_0.2 was optimized based on the comprehensive performance of the studied alloys. The product hydrogen with a pressure of 100 MPa could be produced from 4 MPa feed gas when hot oil was used as a heat reservoir.     

Laves phase hydrogen storage alloys for super-high-pressure metal hydride hydrogen compressors

Ti-Cr- and Ti-Mn-based alloys were prepared to be low- and high-pressure stage metals for a double-stage super-high-pressure metal hydride hydrogen compressor. Their crystallographic characteristics and hydrogen storage properties were investigated. The alloy pair Ti<,0.9>Zr<,0.1>Mn<,1.4>- Cr<,0.35>V<,0.2>Fe<,0.05>/TiCr<,1.55>Mn<,0.2>Fe<,0.2> was optimized based on the comprehensive performance of the studied alloys. The product hydrogen with a pressure of 100 MPa could be produced from 4 MPa feed gas when hot oil was used as a heat reservoir.     

Cluster-based composition rule for Laves phase-related BCC solid solution hydrogen storage alloys

A new cluster line approach for the composition rule of Laves phase-related BCC solid solution hydrogen-storage alloys was presented. The cluster line in a ternary phase diagram refers to a straight composition line linking a specific binary cluster to the third element. In the Laves phase-related BCC solid solution alloy system such as Ti-Cr-V, Ti-Cr tends to form binary Cr2Ti Laves phase while Ti-V and Cr-V to form solid solutions. This Laves phase is characterized by a close-packing icosahedral cluster Cr7Ti6. A cluster line Cr7Ti6-V is then constructed in this system. Alloy rods with a diameter of 3 mm of compositions along this line were prepared by copper-mould suction method. The alloy structure is found to vary with the V contents. Furthermore, the P-C-T measurements indicate that the cluster-line (Cr7Ti6)1-xVx alloys have large hydrogen storage capacities.     

TiCrMo三元储氢合金的结构和性能

采用XRD、SEM和PCT法研究Mo取代TiCr1.8合金中的部分Cr对其结构和储氢性能的影响。XRD测试结果表明,随着合金中Mo取代Cr的量的增加,合金的相组成首先转变为MoCr体心立方(BCC)相与Laves相共存,Laves相的含量逐渐降低;当Mo含量超过一定量时,合金的相组成转变为MoCrBCC相与微量的α-Ti相共存;MoCrBCC相的晶胞参数随合金中Mo含量的增加而增大。合金的压力组分温度(PCT)测试结果表明,合金的吸氢量随合金中Mo含量的增加而减少。     

Sn对稀土系贮氢合金性能的影响

研究了Ｓｎ替代贮氢合金ＬａＮｉ５、ＭｌＮｉ５（Ｍｌ＝富镧混合稀土）中部分Ｎｉ对合金的结构、吸氢容量和平衡氢压等性能的影响。用Ｘ射一衍射进行物相分析,测试了２９８Ｋ,３１３Ｋ、３３３Ｋ温度下合金的吸、放氢ｐ－ｃ－ｔ曲线。结果表明：ＮｌＮｉ５ｘＳｎｘ合金（ｘ＝０,０．１）为六方晶体结构的单相组织。以Ｓｎ部分取代ｎｉ,使平台压力阴低吸、放氢滞后减小,而吸氢能力降低很小。利用电负性、电子浓度及原了尺寸等参     

Effect of Ti content on the hydrogen storage properties of Zr1-xTixMn2Ce0.015 alloys

The effect of Ti content on the hydrogen storage properties of Zr1-xTixMn2 Ce0.015 (x = 0,0.2,0.3,0.5) alloys was studied by X-ray diffraction, scanning electron microscopy and pressure-composition (p-c) isotherm measurement. All of the alloys mainly consist of C14-type Laves and CeO2 phases. As the Ti content increases, the lattice parameters of the Laves phase decrease and the unit cell shrinks anisotropically, the total hydrogen absorption capacity decreases but the reversible hydrogen desorption capacity of the alloys increases, and the equilibrium pressure of the alloys increases but the plateau becomes sloping. The changes of hydrogen storage properties of Zr1-xTixMn2 Ce0.015 alloys are related to the differences in both atomic radius and hydrogen affinity between Ti and Zr elements.     

低钴含硅LaNi_5型储氢合金

用悬浮熔炼法制备了不同含硅量的低钴LaNi5型储氢合金 ,用XRD法测定其结构 ,并测试了电化学容量和寿命 ,分析了Si含量对性能的影响 ,合成了新型储氢合金La0 .8Nd0 .2 Ni3 .6Co0 .4Mn0 .4A10 .3 Cu0 .1Fe0 .1Si0 .1,其比容量为 30 3mAh/g ,30 0次循环后的容量还有其最高容量的 84 %。     

镀铜处理Ti-Mn基储氢合金电极的电化学性能

采用化学镀铜的方法对Ti0 .2 6Zr0 .0 7V0 .2 3Mn0 .1 3Ni0 .3Cr0 .0 1 储氢合金进行表面包覆处理 ,研究了包覆合金电极的电化学性能。实验结果表明 ,经过包覆镀铜处理的Ti0 .2 6Zr0 .0 7V0 .2 3Mn0 .1 3Ni0 .3Cr0 .0 1 储氢合金活化性能有所降低 ,最大电化学容量略有减小 ,而循环稳定性有了显著的提高。其主要原因在于包覆镀铜处理在一定程度上延缓了合金与电解液之间的氧化腐蚀反应 ,循环伏安特性曲线的测量结果证实了这一点。     

Large-scale production and quality assurance of hydrogen storage (battery) alloys

The new generation of high-capacity metal hydride rechargeable batteries is a cadmium-free energy alternative to current types of accumulators. While the first steps were made for consumer wireless applications, the newest developments aim toward traction systems (zero-emission cars). This article introduces the materials selection, quality control, and production principles of alloy systems suitable for storing hydrogen either electrochemically or by gas absorption. Examples of Zr-Ni, Ti-Mn₂, and rare earth-Ni₅ are demonstrated from the metallurgical standpoint. These alloys (currently produced in large scale— tons/day) are now used in industry after approximately 20 years of development.     

稀土系贮氢合金的生成焓计算

利用Miedema理论和几何模型计算了二元合金系La M ,Ni M和三元合金系LaNi5-xMx(M =Co ,Mn ,Al,Cr ,Fe,Cu)的生成焓。对二元合金系 ,计算结果与已有实验结果在xM ≥ 70 % (摩尔分数 )范围符合得较好 ;三元合金系计算结果表明 ,当分别添加合金组元Mn ,Co ,Cr,Fe和Cu时 ,LaNi5-xMx 的生成焓不同程度地增大 ,其中Cr ,Fe和Mn的影响较大 ,而添加Al时生成焓明显减小。讨论了生成焓对合金高温氢化时发生歧化反应的影响 ,合金的生成焓越大 ,越有利于歧化反应。     

低钴AB_5型贮氢合金的制备及电化学性能

为了降低镍氢电池的原材料成本 ,研究了一系列多元、低钴和无钴AB5型贮氢合金 ,以及取代元素对贮氢合金电化学性质的影响。结果显示 ,用少量的铁、铜和铬部分取代贮氢合金La(NiMnCoAl) 5中的钴对改善贮氢合金电化学循环稳定性有效。贮氢合金La(NiMnAl) 4.6(FeCuCr) 0 .2 Co0 .2 具有满意的循环稳定性 ,它在 0 .2C放电条件下的最大放电容量为 2 96mAh/g-1,经过 30 0次循环容量衰减仅 2 1.8%。另外 ,还用X射线衍射检测了贮氢合金的微观结构     

Mn nanoparticles enhanced dehydrogenation and hydrogenation kinetics of MgH2 for hydrogen storage

Mn nanoparticles (nano-Mn) were successfully synthesized and doped into MgH₂ to improve its de/hydrogenation properties. Compared with MgH₂, the onset desorption temperature of 10 wt.% nano-Mn modified MgH₂ was decreased to 175 °C and 6.7, 6.5 and 6.1 wt.% hydrogen could be released within 5, 10 and 25 min at 300, 275 and 250 °C, respectively. Besides, the composite started to take up hydrogen at room temperature and absorbed 2.0 wt.% hydrogen within 30 min at low temperature of 50 °C. The hydrogenation activation energy of MgH₂ was reduced from (72.5±2.7) to (18.8±0.2) kJ/mol after doping with 10 wt.% nano-Mn. In addition, the MgH₂ + 10 wt.% nano-Mn composite exhibited superior cyclic property, maintaining 92% initial capacity after 20 cycles.     

有机液体储氢技术中催化剂应用的研究进展

近年来,随着氢能的快速发展,储氢问题日益突出。有机液体储氢技术凭借其高密度、高储氢效率、高安全性的等优势,在氢气储运市场占据一席之地。目前,国外对此项技术的研究和应用较多,而国内的研究报道较少,应用也几近空白。本文主要介绍了有机液态储氢技术优势及难点,重点对目前国内外研究现状进行了阐述。通过对国内外加氢、脱氢贵金属催化剂和非贵金属催化剂研究现状的介绍,将为开发高效低成本加氢脱氢催化剂,研究最适宜的加氢与脱氢条件,推动液态有机物储氢技术大规模的应用与发展,提供可能性。     

Effect of commercial AB5 alloy addition on the electrochemical properties of Ml-Mg-Ni-based hydrogen storage alloys

A commercial AB5 hydrogen storage alloy was used as an additive to improve the electrochemical properties of Ml-Mg-Ni-based hydrogen storage alloys.The effect of AB5 alloy addition on the phase structure,charge/discharge characteristics,and electrochemical kinetics of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 alloy was investigated.The maximum discharge capacity of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 + 4 wt.% AB5 electrode reaches 406 mAh/g.The anodic polarization,cyclic voltammetry,and potential step discharge experiments show that the electrochemical kinetics of the electrode with additives was promoted,with the LaNi5 phase of AB5 alloy acting as electro-catalytic sites in the electrode alloy.The high-rate dischargeability of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 + 4 wt.% AB5 alloy electrode at 1100 mA/g reaches 60.9%,which is 9.4% higher than that of Ml0.90Mg0.10Ni3.08Mn0.13Co0.63Al0.14 alloy electrode.The cycling stability of the electrode with 4 wt.% AB5 alloy has also been improved.     

Electrochemical performances of hydrogen storage alloys treated using a new milling technique

A new self-made additive of amidocyanogen-acetic salt was used in wet bail-grind technique (WBGT) for preparing hydrogen storage alloys, and the effect on the electrochemical performance of the alloy electrode was investigated in detail. It was found that the prepared electrode had perfect electrochemical performances, such as rapid activation, high capability, high-rate discharge (HRD) ability, and good stability. The first discharge capacitance at 0.2 C (throughout this study, n C rate means that the rated capacity of a hydrogen storage alloy (full capacity) is charged or discharged completely in 1/n h) reached 278mAh.g-1 and the discharge capacitance reached the maximum of 322mAh·g-1 only after two charge-discharge cycles. For the dry method, wet method, and WBGT, the high rate discharge (HRD) values (C5C/C0.2C ratio) were approximately 0.59, 0.76, and 0.83, respectively. The stable discharge capacity at 3 C increased from 275mAh·g-1 (dry method) to 295mAh·g-1 (WBGT).     

合金化对ZrMn2基Laves相贮氢合金相组成的影响

研究了Ni、V、Cr、Co、Fe、Cu和Ti等合金化元素取代ZrMn2 基Laves相贮氢合金的B侧或A侧对合金相组成的影响。结果表明 ,采用不同的元素对A侧或B侧进行部分取代 ,将引起ZrMn2 基合金相组成的变化。采用Ni取代Mn后 ,ZrMn2 合金的主相结构转变为C15型Laves相 ,表明Ni为C15相稳定元素。对Zr Mn Ni三元合金 ,V为C14相稳定元素 ,而Co、Fe、Cu则为C15相稳定元素。取代量较少时 ,Cr为C15相稳定元素 ,取代量增加时 ,C15相稳定作用减弱。Ti元素为C14相稳定元素 ,Ti对Zr的部分取代将导致合金主相结构转变为C14型Laves相。合金化元素对ZrMn2 合金的相组成的影响与元素的电子浓度和原子尺寸不同有关     

Effects of annealing treatment on the microstructure and electrochemical properties of low-Co hydrogen storage alloys containing Cu and Fe

The effects of annealing treatment on the microstructure and electrochemical properties of low-Co LaNi_3.55Mn_0.35Co_0.20Al_0.20Cu_0.75Fe_0.10 hydrogen storage alloys were investigated. X-ray diffraction (XRD) analysis indicated that annealing treatment remarkably reduced the lattice strain and defects, and increased the unit-cell volume. The optical microscope analysis showed that the as-cast alloy had a crass dendrite microstructure with noticeable composition segregation, which gradually disappeared with increasing annealing temperature, and the microstructure changed to an equiaxed structure after annealing the alloy at 1233 K. The electrochemical tests indicated that the annealed alloys demonstrated much better cycling stability compared with the as-cast one. The capacity retention at the 100th cycle increased from 90.0% (as-cast) to 94.7% (1273 K). The annealing treatment also improved the discharge capacity. However, the high rate dischargeability (HRD) value of the annealed alloy slightly dropped, which was believed to be ascribed to the decreased exchange current density and the hydrogen diffusion coefficient in alloy bulk.     

Effects of annealing treatment on the microstructure and electrochemical properties of low-Co hydrogen storage alloys containing Cu and Fe

The effects of annealing treatment on the microstructure and electrochemical properties of low-Co LaNi3.55Mno.35Co0.20Al0.20Cuo.75Fe0.10 hydrogen storage alloys were investigated.X-ray diffraction (XRD) analysis indicated that annealing treatment remarkably reduced the lattice strain and defects,and increased the unit-cell volume.The optical microscope analysis showed that the as-cast alloy had a crass dendrite microstructure with noticeable composition segregation,which gradually disappeared with increasing annealing temperature,and the microstructure changed to an equiaxed structure after annealing the alloy at 1233 K.The electrochemical tests indicated that the annealed alloys demonstrated much better cycling stability compared with the as-cast one.The capacity retention at the 100th cycle increased from 90.0％(as-cast) to 94.7％ (1273 K).The annealing treatment also improved the discharge capacity.However,the high rate dischargeability (HRD)value of the annealed alloy slightly dropped,which was believed to be ascribed to the decreased exchange current density and the hydrogen diffusion coefficient in alloy bulk.     

快速凝固富钛Ti-V合金的微观组织和储氢性能

研究目的在于优化Ti0.8-0.9V0.2-0.1二元合金的相结构成分、微观组织和储氢性能。该合金主要用于从含有大量一氧化碳的高温气态混合物中吸收氢气。Ti0.8-0.9V0.2-0.1合金中的α-（HCP）和β-（BCC）相在纯氢气中基于氢化作用,形成单相FCC结构的氢化物,此过程与合金的化学成分无关。同步辐射X射线衍射的原位分析表明,在含有氢气和10%一氧化碳的混合气体中,只有β相转变成相应的氢化物。快速凝固（RS）处理细化了Ti0.8V0.2和Ti0.9V0.1合金的晶粒组织,而且,快速凝固处理增加了Ti0.9V0.1合金中的β相,其所占比例是普通熔铸条件下的两倍。扫描电子显微镜（SEM）分析表明,Ti0.9V0.1合金含有片状组织,层片的厚度约为300nm。热脱附谱（TDS）显示,微观组织的细化可以加快氢脱附的动力学过程。     

Effect of photocatalyst on performance of LaNi5 hydrogen storage alloy electrodes

Photocatalyst hydrogen storage alloys（PHSA） with different photocatalyst contents were synthesized by mechanical blend method. The effects of the photocatalyst on the electrochemical performance of the PHSA were studied. The resutts indicate that the PHSA electrodes show better activation performance when UV irradiation is present. The high rate discharge performance as well as cycle performance is improved compared with that of the AB5 alloys, The PHSA shows the best performance when the photocatalyst content is 20%.