Mgx／Mg2Ni复合储氢合金的机械合金化制备及电极性能

利用Mg2Ni合金和不同质量百分数的Mg粉(x=10％，30％，50％)混合后球磨制得Mgx／Mg2Ni复合合金。XRD分析证实，Mg2Ni合金和Mg粉混合球磨时无新相生成，Mg粉的添加可有效抑制Mg2Ni合金单独球磨时存在的Mg2Ni相的分解反应。采用模拟电池法测试了Mgx／Mg2Ni复合合金的电极性能，结果表明，Mg量的增加可显著地提高复合合金的放电容量。在球磨的开始阶段，复合合金的放电容量随球磨时间的延长而增加，球磨一定时间后，其放电容量则随球磨时间的延长而迅速降低。放电容量与球磨时间的变化关系体现了球磨对复合合金微结构改变的影响。     

Lao.7Mgo.3Ni2.8Coo.5-xFex系列合金的制备及其储氢性能

在制备La-Ni-Co-Fe中间合金的基础上,采用机械合金化方法制备La0.7Mg03Ni2.8C005-xFex(x=0,0.1,0.2,0.3,0.4,0.5)系列储氢合金,研究在不同球磨时间下储氢合金的物相、微观形貌和电化学性能及元素置换对其储氢性能的影响.结果表明La0.7Mg0.3Ni2.8Co0.5合金的主相为LaNi5相,La0.7Mg0.3Ni2.8Co0.5-xFex系列储氢合金球磨40h和80h后,主相为LaNi5相和少量LaMg2Ni9相;且随着球磨时间的增加,合金晶粒变细小,La0.7Mg03Ni2.8Co0.5合金的最大放电容量呈变大的趋势,从142.4mA.h/g增加到157.5mA.h/g,La0.7Mg0.3Ni2.8Co0.2Fe0.3合金的最大放电容量从150.7mA·h/g增加到162.1mA·h/g,合金具有较好的循环稳定性能.     

La_(0.7)Mg_(0.3)Ni_(2.8)Co_(0.5-x)Fe_x系列合金的制备及其储氢性能

在制备La-Ni-Co-Fe中间合金的基础上,采用机械合金化方法制备La0.7Mg0.3Ni2.8Co0.5-xFex(x=0,0.1,0.2,0.3,0.4,0.5)系列储氢合金,研究在不同球磨时间下储氢合金的物相、微观形貌和电化学性能及元素置换对其储氢性能的影响。结果表明:La0.7Mg0.3Ni2.8Co0.5合金的主相为LaNi5相,La0.7Mg0.3Ni2.8Co0.5-xFex系列储氢合金球磨40 h和80 h后,主相为LaNi5相和少量LaMg2Ni9相;且随着球磨时间的增加,合金晶粒变细小,La0.7Mg0.3Ni2.8Co0.5合金的最大放电容量呈变大的趋势,从142.4 mA.h/g增加到157.5 mA.h/g,La0.7Mg0.3Ni2.8Co0.2Fe0.3合金的最大放电容量从150.7mA.h/g增加到162.1mA.h/g,合金具有较好的循环稳定性能。     

Ni对高能球磨Mg-Ni合金组织和电化学性能的影响

利用高能球磨工艺制备了不同Ni含量的Mg-Ni合金，采用X射线衍射分析，研究了随Ni含量变化以及球磨时间不同合金组织演变过程，并对其电化学放电容量进行了测试分析。结果表明，随着Ni含量由Mg2Ni，Mg1．5Ni到MgNi的增加，高能球磨Mg—Ni合金体系经历纳米晶Mg2Ni向非晶MgNi过渡并最终形成纳米晶MgNi合金的转变过程。不同组织状态的Mg-Ni合金其电化学容量有较大的差异。随着Ni含量提高，纳米晶MgNi合金增加，在有纳米晶Ni的存在下，Mg-Ni合金的放电容量可高达500mAh／g。延长球磨时间，获得几乎完全纳米晶的MgNi合金组织，由于没有纳米晶Ni的催化作用，导致合金放电容量下降。     

复合储氢合金Mg1.8Zr0.2Ni- (1.2-x)Ni -xMgTi3结构和电化学性能研究

为改善Mg₂Ni储氢合金电化学性能,采用机械合金化法(Mechanical Alloying,MA),分别制备出改性合金Mg_1.8 Zr Ni以及MgTi₃,按一定比例和Ni混合球磨,制备出纳米晶或非晶化的Mg_1.8Zr_0.2Ni- (1.2-x)Ni -xMgTi₃复合储氢合金。研究结果表明,经部分取代改性和包覆修饰后的复合储氢合金,其表面和内部形成较多的纳米级褶皱、空隙层状和多相结构缺陷。随着MgTi₃含量增加,Mg_1.8Zr_0.2Ni- (1.2-x)Ni -xMgTi₃复合储氢合金初始放电比容量也逐渐增加,当MgTi₃含量为x=0.5时,合金初始放电比容量为973.3 mAh.g_-1。但MgTi3含量超过x=0.5时,其初始放电比容量又有所下降,研究表明添加MgTi₃却不利于复合储氢合金的循环稳定性和高倍率放电性能。通过对Mg_1.8Zr_0.2Ni- (1.0-x)Ni -xMgTi₃复合储氢合金进行线性极化、阳极极化和交流阻抗测试,进一步研究了系列合金电极的表面电化学反应、电荷转移过程、氢在合金中的扩散情况以及它们的电化学性能。     

Electrochemical Properties of MgNi-ZrB Hydrogen Storage Alloys

通过机械球磨法制备了一系列的Mg Ni、Zr B和Mg Ni-Zr B储氢合金。通过XRD、SEM、充放电性能、循环伏安、塔菲尔极化曲线、交流阻抗测试,研究了Zr B的添加对Mg Ni合金的储氢性能的影响。结果表面,Zr B的添加大大提高了Mg Ni合金的电化学性能。球磨15 h的Mg Ni-Zr B(100:5)复合物体现出最好的电化学性能,循环20周和50周时的放电容量分别为226和209 m Ah·g-1,远远高于Mg Ni合金的放电容量。动态极化曲线和交流阻抗测试显示Zr B的添加极大的提高了Mg Ni合金的抗腐蚀性能和电化学动力学性能。     

MgNi-ZrB储氢合金的电化学性能(英文)

通过机械球磨法制备了一系列的Mg Ni、Zr B和Mg Ni-Zr B储氢合金。通过XRD、SEM、充放电性能、循环伏安、塔菲尔极化曲线、交流阻抗测试,研究了Zr B的添加对Mg Ni合金的储氢性能的影响。结果表面,Zr B的添加大大提高了Mg Ni合金的电化学性能。球磨15 h的Mg Ni-Zr B(100:5)复合物体现出最好的电化学性能,循环20周和50周时的放电容量分别为226和209 m Ah·g-1,远远高于Mg Ni合金的放电容量。动态极化曲线和交流阻抗测试显示Zr B的添加极大的提高了Mg Ni合金的抗腐蚀性能和电化学动力学性能。     

La1＋xMg2-xNi9（x=0，0．5，1．0，1．5）合金的储氢性能及电化学性能研究

利用高频熔炼方法制备了La1＋xMg2-xNi9（x=0，0．5，1．0，1．5）系列合金，并对其进行了XRD分析和储氢容量及电化学性能测定。结果表明：随着La含量增大，合金中LaNi5和（La，Mg）Ni3相转变为LaNi3相，且Mg2Ni相出现，晶胞体积也增大，合金的储氢容量和电化学性能提高；当x=1．5时，Mg2Ni相消失，合金的储氢性能有所下降。当x=1．0时，即La2MgNi9合金具有较好的储氢容量及电化学容量。     

PLC控制的球磨法制备镁基储氢合金性能研究

通过PLC控制的球磨法制备了Mg2Ni镁基储氢合金,并对其物相组成、放电性能和循环稳定性进行了研究。结果表明,采用PLC控制技术有利于提高球磨储氢合金的放电性能和循环稳定性。与未采用PLC制备技术相比,采用PLC技术使Mg Ni合金的放电容量增加了78.77%,经过20次充放电循环后的放电效率从4.64%提高到63.72%。     

铝含量对Mg_(2-x)Al_xNi镁基储氢新能源汽车电池合金性能的影响

电化学循环稳定性和耐碱液腐蚀性能较差制约了镁基储氢新能源汽车电池合金的发展。采用球磨后烧结的两步法制备了Mg_(2-x)Al_xNi(x=0,0.1,0.2,0.3,0.4,0.5)储氢新能源汽车电池合金试样,并进行了显微组织、充放电循环和耐碱液腐蚀试验及分析。结果表明:随Al含量增加,合金放电容量衰减率先减小后增大,腐蚀电位先正移后负移,合金电化学循环稳定性和耐碱液腐蚀性能先提高后下降。Mg_(2-x)Al_xNi(x 0.3)合金内部"白亮颗粒"大小不一、分布均匀性较差; Mg_(2-x)Al_xNi(x=0.4)合金内部"白亮颗粒"尺寸较为一致呈均匀分布; Mg_(2-x)Al_xNi(x=0.5)合金内部"白亮颗粒"尺寸和缺陷体积均明显增大。与Mg_2Ni相比,Mg_(2-x)Al_xNi(x=0.4)合金充放电循环10次后的放电容量衰减率从60%减小至36%,腐蚀电位从-0.946 523 V正移至-0.907 812 V,合金具有最佳的电化学循环稳定性和耐碱液腐蚀性能。     

高能球磨在MmNi_(5-x)(Co,Al,Mn)_x/Mg体系中诱发的固态反应及纳米相复合储氢合金的形成

借助Ｘ射线衍射及透射电镜研究了ＭｍＮｉ(５－ｘ)（Ｃｏ,ＡＩ,Ｍｎ）ｘ／Ｍｇ混合粉末在高能球磨过程中的相交及其结构变化,证实高能球磨过程中ＭｍＮｉ(５－ｘ)（Ｃｏ,Ａｌ,Ｍｎ）ｘ与Ｍｇ之间发生了固态反应,并最终形成了纳米相复合结构．通过精确测定点阵常数和用Ｍｉｅｄｅｍａ方法估算反应的生成热,给出了可能的固态反应的反应式吸氢特性测定表明球磨制备的纳米相复合储氢合金有较好的性能通过对球磨后再退火的样品进行分析,进一步研究了所获得纳米相复合结构稳定性及其相交     

机械球磨Mg2Ni0．95Sn0．05＋x％Ni非晶复合物的微结构和电化学性能

用机械球磨法合成了Mg2Ni0．95Sn0．05＋x％Ni（质量分数，x=25，50，75，100，125）非晶复合物，研究了其微结构和电化学性能。微结构分析表明，不添加Ni粉的Mg2Ni0．95Sn0．05合金经100h球磨后仍然难以形成非晶结构，加入镍粉有助于非晶结构的形成。电化学研究表明，铸态最大放电容量仅为16mAh／g，球磨100h后容量改善不明显；加入Ni粉球磨后，容量大幅上升，随着Ni添加量的增加，复合物最大放电容量先增后减，在x=75时达到最大值625.6mAh／g。把x=50时的复合物，延长球磨时间t，复合物最大放电容量提高，当t=200h时达到670mAh／g。     

Mn含量对Mg2Ni型合金相形成及放电性能的影响

采用按比例混合合金粉末压制成圆柱试样，然后用低温烧结和随后机械球磨的方法制备了非晶态的Mg2Ni型合金。研究了烧结和球磨对不同Mn含量的Mg2Ni型合金的相形成过程及电化学性能的影响。实验表明：在Mg2Ni中采用第三组元Mn对Mg进行适量的替代后，通过烧结及球磨方法可以获得均匀的非晶相；微量替代可有效地提高其放电容量：随替代量的增加，合金最大放电容量和高速放电能力降低，而充放电循环稳定性提高。     

Structure and Electrochemical Hydrogen Storage Properties of as-Milled Mg-Ce-Ni-Al-Based Alloys

At room temperature,crystalline Mg-based alloys,including Mg_2 Ni,MgNi,REMg_(12) and La_2 Mg_(17),have been proved with weak electrochemical hydrogen storage performances.For improving their electrochemical property,the Mg is partially substituted by Ce in Mg-Ni-based alloys and the surface modification treatment is performed by mechanical coating Ni.Mechanical milling is utilized to synthesize the amorphous and nanocrystalline Mg_(1-x)Ce_xNi_(0.9)Al_(0.1)(x=0,0.02,0.04,0.06,0.08)+50 wt%Ni hydrogen storage alloys.The effects made by Ce substitution and mechanical milling on the electrochemical hydrogen storage property and structure have been analyzed.It shows that the as-milled alloys electrochemically absorb and desorb hydrogen well at room temperature.The as-milled alloys,without any activation,can reach their maximal discharge capacities during first cycling.The maximal value of the 30-h-milled alloy depending on Ce content is 578.4 mAh/g,while that of the x=0.08 alloy always grows when prolonging milling duration.The maximal discharge capacity augments from337.4 to 521.2 mAh/g when milling duration grows from 5 to 30 h.The cycle stability grows with increasing Ce content and milling duration.Concretely,the S_(100) value augments from 55 to 82% for the alloy milled for 30 h with Ce content rising from 0 to 0.08 and from 66 to 82% when milling the x=0.08 alloy mechanically from 5 to 30 h.The alloys' electrochemical dynamics parameters were measured as well which have maximum values depending on Ce content and keep growing up with milling duration extending.     

Structure and electrochemical performance of hydrogen storage alloy La0.7Mg0.3Ni2.875Co0.525Mn0.1-boron composite

The structure and electrochemical characteristics of La0.7Mg0.3Ni2.875Co0.525Mn0.1-boron composite was studied systematically. The AB3 type hydrogen storage alloys La0.7Mg0.3Ni2.875Co0.525Mn0.1 were successfully synthesized by means of inter-media alloy La2Mg17 . The alloys were composited with boron at different weight rate. From the XRD analyses, each alloy of this series is mainly composed of (La,Mg)Ni3 phase and the LaNi5 phase, and the phase abundance of each phase varies with the boron weight rate, moreover, after composition, the c and cell volumes of (La,Mg)Ni3 phase increase, and the LaNi5 phase keep the same, which indicate that the boron may enter (La,Mg)Ni3 phase. The electrochemical studies show that the maximum discharge capacity of the composites decreases, but the cycling life improved. And the high rate discharge ability and exchange impendence spectroscopy (EIS) of the AB3 alloys and its composite were also studied.     

Structure and electrochemical performances of Mg_(20-x)Y_xNi_(10)(x=0-4) alloys prepared by mechanical milling

Mg_2Ni-type Mg_(20-x)Y_xNi_(10)(x=0,1,2,3 and4) electrode alloys were fabricated by vacuum induction melting.Subsequently,the as-cast alloys were mechanically milled on a planetary-type ball mill.The effects of milling time and Y content on the microstructures and electrochemical performances of the alloys were investigated in detail.The results show that nanocrystalline and amorphous structure can be successfully obtained through mechanical milling.The substitution of Y for Mg facilitates the glass forming of the Mg_2Ni-type alloy and significantly enhances the electrochemical characteristics of the alloy electrodes.Moreover,the discharge capacity of Y-free alloy monotonously grows with the milling time prolonging,while that of the Y-substituted alloys has the maximum values in the same case.The milling time of obtaining the greatest discharge capacity markedly decreases with Y content increasing.The electrochemical kinetics of the alloys,including high rate discharge ability(HRD),diffusion coefficient(D),limiting current density(I_L) and charge transfer rate,monotonously increase with milling time extending.     

Properties of Mechanically Milled Nanocrystalline and Amorphous Mg–Y–Ni Electrode Alloys for Ni–MH Batteries

Nanocrystalline and amorphous Mg2Ni-type Mg20-xYxNi10(x = 0,1,2,3 and 4) electrode alloys were fabricated using mechanical milling.The effects of the Y content and milling time on the microstructures and electrochemical performances of the alloys were investigated in detail.X-ray diffraction and transmission electron microscopy analyses revealed that the substitution of Y for Mg yields an obvious change in the phase composition and micro morphology of the alloys.When the Y content x B 1,the substitution of Y for Mg does not change the major phase Mg2 Ni,but with a further increase in the Y content,the major phase of the alloys transforms into the YMg Ni4 YMg3 phase.A nanocrystalline and amorphous structure can be obtained by mechanical milling,and the amorphisation degree of the alloy visibly increases with increased milling time.Electrochemical measurements indicate that the discharge capacity of the alloys first increases and then decreases with increasing Y content and milling time.The substitution of Y for Mg dramatically ameliorates the cycle stability of the as-milled alloys,and the mechanical milling more or less impairs the cycle stability of the alloys.Furthermore,the high rate discharge ability,electrochemical impedance spectrum,Tafel polarisation curves and potential step measurements indicate that the electrochemical kinetic properties of the as-milled alloys first increase and then decrease with increasing Y content and milling time.     

A2B7型La0.75Mg0.25Ni3．5-xAlx（x=0-0．3）合金相结构及电化学性能

采用感应熔炼方法制备了A2B7型La0.75Mg0.25Ni3．5-xAlx（x=0，0．02，0．06 0.1，0．3）四元贮氢合金，系统研究了Al元素部分替代Ni对A2B7型La0.75Mg0.25Ni3．5合金相结构及电化学性能的影响。X射线衍射（XRD）分析表明：La0.75Mg0.25Ni3．5由单一La2Ni7相组成：Al元素加入后，开始出现CaCu5型LaNi5相，当x=0．3时，LaNis相成为合金的主相。Rietveld分析表明：随着Al含量的增加，LaNi5相逐渐增多，Al的加入利于CaCu5型LaNi5相的形成。电化学测试表明：Al替代Ni对A2B7型合金La0.75Mg0.25Ni3．5电极活化性能影响不大：而最大放电容量随Al在La0.75Mg0.25Ni3．5-xAlx，合金中替代量的增加而减小。当放电电流密度为1600mA／g时，合金的倍率放电性能由68.8％（x=0）增加到81．16％（x=0．1）然后减小到65．67％（x=0.3）。此外，La0.75Mg0.25Ni3．5-xAlx合金电极循环稳定性先增加而后下降。x=0．06时合金电极容量保持率最大（S100=85.21．％）。