储氢合金的研究与应用

简述了金属氢化物贮氢原理；对稀土基、AB2型Laves相、BCC固溶体型以及Mg基储氢合金的最新进展进行了简要综述；简述了储氢合金作为储氢容器、Ni／MH电池、氢化物热泵、催化剂和氢的提纯等领域的应用；简析了储氢合金存在的储氢容量低、粉化以及性能衰减等技术难题；并对储氢合金的发展前景进行了展望。     

Hydrogen storage alloys for high-pressure suprapure hydrogen compressor

In this work, AB₅ type rare earth-based and AB₂ type TiCr₂-based hydrogen storage alloys were studied for the purpose of high-pressure hydrogen compression. A pair of hydrogen storage alloys, Ml_0.55Mm_0.2Ca_0.25Ni₅ (Ml: La-rich mischmetal; Mm: Ce-rich mischmetal) and (Ti_0.97Zr_0.03)_1.1Cr_1.6Mn_0.4, with favorable hydrogen storage properties was developed as the alloys for a double-stage high-pressure metal hydride hydrogen compressor (MHHC). With the developed alloy pair, we designed and built a MHHC prototype with hydrogen capacity of 100 L, which could produce high-pressure ultrapure hydrogen with pressure of 45 MPa and purity of 99.9999% from industrial grade hydrogen (98% purity) at pressure of around 2 MPa. During the compression procedure, only hot water is used as the heating source. The compression characteristics were studied and the thermal efficiency was calculated.     

Ml—Ca—Ni系储氢合金的储氢特性及其在氢—汽油混合燃料车中的应用

系统研究了稀土系Ml-Ca-Ni（Ml：富镧混合稀土）储氢合金的储氢特性。实验结果表明,该系列合金吸放氢量大、动力学性能优良,其中,合金Ml0.8Ca0.2Ni5的吸放氢量可达180ml/g以上。以储氢合金Ml0.8C0.2Ni5氢化物作为氢的储存方式,研制了20Nm^3氢容量的车用燃料箱,以燃料箱作为氢源对汽油机进行台架对比试验,结果表明：氢-汽油混合燃料发动机可节省汽油30%,发动机相对热效率提高10%以上,发动机排出的CO含量减少70%以上,HC、NOx含量也降低;以燃料箱作为供氢系统进行了氢-汽油混合燃料车道路示范性试验。     

金属氢化物氢压缩机用AB2型Ti- Mn基储氢合金研究

制备了AB2型Laves相Ti- Zr- Mn- Cr- V- Fe系列氢压缩材料,对于V- Fe、Mn/Cr比值和Zr含量对合金吸放氢平台特性和热力学性能的影响进行了研究,优化出具有优异综合储氢性能的氢压缩材料Ti0.9Zr0.1Mn1.4Cr0.35V0.2Fe0.05合金.该合金具有较低的吸放氢平台压力、较小的压...     

Ti-Cr基合金的储氢性能及晶体结构

研究了Ti1＋xCr1.2Mn0.8（x=0．0,0．1,0．2,0．3）系和Ti1＋xCr1.2Mn0.8-6My（M=Fe,Ni,Cu,V,VFe;x=0．0,0．1;y=0．1,0．3）系AB2型合金的储氢性能和晶体结构．XRD结果表明,合金主相为C14（MgZn2）型Laves相,可以保证较高的吸、放氢量．通过A侧过化学计量以及B侧用Fe,Ni,Cu,V,VFe分别替代部分Mn,增加了点阵常数和晶胞体积,降低了P—C—T曲线的滞后．由相应数据寻找出适合于金属氢化物氢压缩机的高压端储氢合金．结果表明,合金TiCr1．2Mn0．5Fe0．3与Ti1.1Cr1.2Mn0.5Cu0.3具有良好的储氢性能和压缩特性,可以作为性能优良的高压端储氢合金．     

微型包覆处理M1（NiCoMnTi）_5合金的电极活化特性

将Ｍ１（ＮｉＣｏＭｎＴｉ）_５合金粉末经表面微型包覆Ｎｉ－Ｐ处理后制备成吸氢电极，研究其活化性能。结果表明，表面包覆Ｎｉ－Ｐ合金的贮氢电极，其放电容量提高，但达到最大循环放电容量的放电次数增加。试验还表明，采用小电流充放电易使贮氢合金电极达到活化状态。     

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.     

稀土-镁-镍基贮氢电极合金的研究进展

具有超结构特征的稀土-镁-镍基贮氢合金作为新一代金属氢化物/镍(MH/Ni)电池负极材料,因其高的放电容量和好的倍率放电性能,是目前贮氢电极合金发展的重点材料之一。本文从材料相结构、贮氢特性和电化学性能之间的关系出发,综述了近年来国内外稀土-镁-镍基AB3型、A2B7型和A5B19型贮氢电极合金的研究进展,为开发兼具高容量和长寿命的新型稀土系贮氢电极合金提供有价值的参考。     

Ti2Ni储氢合金的充放电特性及腐蚀行为

通过球磨晶态Ti2Ni合金制备非晶态Ti2Ni合金,采用X射线衍射、充放电测试、阳极极化曲线对不同结构的Ti2Ni储氢合金的充放电特性及腐蚀行为进行研究。结果表明:晶态Ti2Ni合金的首次电化学充氢容量可达480mAh/g,但首次放氢量仅为充氢量的一半,合金内形成了大量不可逆氢化物相。随后的充放电循环中几乎没有不可逆相的形成。非晶相能够有效抑制充氢过程中不可逆相的形成,且充放氢使非晶合金间隙发生了弹性变形。此外,非晶结构使合金在碱性电解液中的自腐蚀电位升高、腐蚀电流降低,显著提高了合金的耐蚀能力。     

Numerical simulation of hydrogen desorption from high-density metal hydride hydrogen storage vessels

Metal hydride (MH) alloys are a promising type of material in hydrogen storage applications, allowing for low-pressure, high-density storage. However, while many studies are being performed on enhancing the hydrogen storage properties of such alloys, there has been little research on large-scale storage vessels which make use of the alloys. In particular, large-scale, high-density storage devices must make allowances for the temperature variations caused by the heat of reaction between hydrogen and MH alloys, which may impact the storage characteristics. In this study, we propose a numerical model for the design and evaluation of hydrogen storage devices using MH alloys. Hydrogen desorption reaction behavior for an alloy is observed in terms of temperature and reaction rate. This behavioral correlation is used as the basis for a comprehensive simulation model of the alloy system. Calculated results are found to be in good agreement with experimentally measured data, indicating that the model may be applied to multiple system geometries, scales, and alloy compositions.     

Hydrogen storage properties of TiMn2-based alloys

Several TiMn₂-based C14 Laves phase alloys were prepared and their hydrogen storage properties studied in order to develop suitable materials for hydrogen storage tank or hydride heat pump applications. It was observed that the plateau characteristic of the stoichiometric alloy AB, was better than that of the non-stoichiometric one. The plateau pressure was effectively decreased by the partial substitution of Zr for Ti, while the slope was increased. The substitution effects of other transition elements, such as Cr, V, Cu, Fe, Ni for Mn, were also examined. It was found that Cr was suitable for decreasing the hysteresis, Cu could flatten the plateau with decreasing storage capacity, and V could effectively lower the plateau pressure without decreasing the storage capacity. The hydriding properties were found to be related to the lattice structures. Considering a careful balance of the substitution effects of the alloying elements, it was found that Ti_0.85Zr_0.15MnCr_0.8V_0.1Cu_0.1 alloy had very good plateau characteristics with considerably small hysteresis and high storage capacity.     

TiCrV hydrogen storage alloy studied by positron annihilation spectroscopy

We have studied the structural changes of Ti₂₄Cr₃₆V₄₀ alloy prepared by arc-melting using positron annihilation spectroscopy and X-ray diffraction (XRD) as functions of the number of hydrogen pressure swing cycles and degassing temperature. As the hydrogen storage capacity decreased with the number of pressure swing cycles, both positron lifetime and XRD peak width increased. Upon hydriding, the crystal structure changed from bcc to bct with increased lattice constants. The increase in positron lifetime is due to the volume expansion caused by hydride formation. After degassing at 500 °C, the hydrogen storage capacity recovered to 95% of the initial level, and the XRD peak width and the lattice constants nearly completely returned to their initial values. However, the positron lifetime was still longer than the initial level suggesting the survival of dislocations. The degradation of hydrogen storage capacity is probably caused by both hydride formation and the generation of dislocations.     

贮氢合金电极材料进展

简要综述贮氢合金电极材料三方面的最近进展 :(1)双相贮氢合金材料 ;(2 )复合贮氢电极材料 ;(3)镁基非晶及钠米晶贮氢电极材料。     

镍氢电池复合贮氢合金负极材料的研究进展

根据复合贮氢合金的母体类型即AB5型稀土合金、AB2型Laves相合金、A2B或AB型Mg系合金、V基bcc固溶体型合金和La-Mg-Ni系新型合金,将Ni/MH电池复合贮氢合金负极材料分为相应的5种类型;综述了此类材料的制备方法、微观结构与电化学性能、分析表征方法及机制研究等,提出了目前研究中存在的问题与不足,并对该类材料的研究发展做了展望.     

贮氢电极合金电化学容量的评价方法

设计了三种电化学测试系统并进行金属氢化物电极电化学性能对比分析，结果表明，开口式三电极系统测出的放电容量明显高于夹片式和模拟电池系统所测出的放电容量，夹片式电极系统测试的结果和模拟电池系统测试的结果比较一致。     

Research on compressor utilizing hydrogen storage materials for application in heat treatment facilities

The design of hydrogen compressor utilizing hydrogen storage alloys for application in heat treatment facilities is presented. This compressor working between 0.02 and 3.3 MPa could be an alternative for a mechanical compressor. In laboratory experiments, a model of the hydride compressor was used (scale 1:13). The compressor model uses LaNi_4.8Sn_0.2 (45 kg) and LaNi_4.25Al_0.75 (3.5 kg) alloys closed in two separate containers equipped with heat exchangers. The alloys were being heated and cooled by oil flowing through the containers. It was noticed that penetration of hydrogen to the alloy bed situated in the lower part of the containers was not sufficient. The experiments have shown a high efficiency of heat exchangers mounted in the container with LaNi_4.8Sn_0.2 (finned tubes) and too small efficiency of heat exchangers mounted in the container with LaNi_4.25Al_0.75 (smooth tubes). The initial research of the stability of alloys subjected to many hydrogen absorption-desorption cycles (207 cycles) was carried out for 0.3–3.3 MPa pressure range (LaNi_4.8Sn_0.2 at 310–450 K) and 0.02–0.3 MPa (LaNi_4.25Al_0.75 at 315–410 K). The desorption isotherm for LaNi_4.8Sn_0.2 at 293 K was also determined.The experiments revealed that energy losses were too high to use the hydride compressor instead of a mechanical compressor in an industrial application. Reducing energy loss would be the most important point of further research.     

Hydrogen absorption–desorption properties of Ti0.32Cr0.43V0.25 alloy

Ti_0.32Cr_0.43V_0.25 alloy specimens were heat treated, and its various hydrogen storage properties were measured at 303 K to examine its potential as a hydrogen storage material. The heat treatment improved not only the total and the effective hydrogen storage capacities, but also the plateau flatness. The heat of hydride formation was approximately −36 kJ/mol H₂. The effective hydrogen storage capacity remained at approximately 2 wt% after 1000 cycles of pressure swing cyclic tests. The hydrogen storage capacity could be recovered almost to the initial state by reactivating the alloy. The hydrogen absorption rate increased with the repetition of cycling for the first several cycles and remained almost constant afterward. At the 504th cycle, more than 98% of the hydrogen was absorbed within the first 2 min. X-ray diffraction (XRD) patterns showed that the crystal structure of the alloy became more amorphous as the number of cycles increased.     

贮氢电极合金的发展（一）

在简要介绍有关贮氢合金及名符其镍-氢化物电池概念的基础上,结合最新发展,对各种贮氢电极合金进行了概述,并概要叙述了各种提高贮氢电极合金电化学性能的工艺方法。     

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.