Effect of preparation conditions on properties of Al-substituted α-Ni（OH）2 prepared by homogeneous precipitation

1INTRODUCTION Nickelhydroxideiswidelyusedasthepositive electrodematerialofNi MH,Ni CdandNi Zn batteries.ItcrystallizesintwopolymorphicformsknownasαNi(OH)2andβNi(OH)2.Duringelec trochemicalcycles,therearetworeversiblereac tionsofnickelhydroxide,namely,α(Ⅱ)γ(Ⅲ)andβ(Ⅱ)β(Ⅲ),respectively[1].However,γNiOOHformsinthelongcyclingprocessofβ(Ⅱ)β(Ⅲ),whichresultsinthemechanicalexpan sionandpoorelectrodepropertiesduetodifferentinterlaminardistancesbetweenγNiOOHandβNiOOH[2].Th…     

Effects of erbium additions on high temperature performance of high power Ni-MH batteries

The Co（Ⅲ）-coated spherical nickel hydroxide powder is optimum as positive electrode of high power Ni-MH battery because of its excellent property. But the performances at high temperature （above 50 ℃） is still not satisfied. In the present paper, the effect of element erbium, used as additive by different methods to prepare positive electrode, on the high temperature performances of the Ni-MH batteries is studied. It is found that the charge acceptance ability of the spherical Ni（OH）2 electrode with element erbium as additive is improved. The discharge capacities of Ni（OH）2 coated with 1% （atomic fraction） Er（OH）3 and mechanically added with 1% （atomic fraction） Er203 at 1C are 12.6% and 11.7%, respectively, higher than those of the samples without erbium at 70 ℃.     

Effect of graphite content on electrochemical performance of Sn-SnSb/graphite composite powders

Sn-SnSb alloy was synthesized by reducing a aqueous solution containing Sn（Ⅱ） and Sb（Ⅲ） salts with NaBH4 in the presence of sodium citrate. The product was characterized by X-ray diffractometry（XRD） and scanning electron microscopy（SEM）. Sn-SnSb/graphite composite powders were prepared by mechanical milling and the mass fraction of graphite was increased from 20% to 50%. The effect of graphite content on the electrochemical performance of Sn-SnSb/graphite composite electrode was investigated. The results show the increase of graphite content is in favor of enhancing the first charge-discharge efficiency and improving the cycle performance, but the capacity of the composite electrode decreases with increasing content of graphite.     

Ni（OH）2 particles synthesized by high energy ball milling

1 Introduction Ni(OH)2/NiOOH has been used as positive materials in alkaline secondary batteries for more than 100 years[1- 3]. The performance improvement of Ni(OH)2/NiOOH electrode is crucial for the application of these batteries as they are all positi…     

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.     

Synthesis and high-temperature performance of Ti substituted α-Ni（OH）2

1 INTRODUCTION The development of electric and hybrid vehi- cles is proceeding against the backdrop of environ- mental problems ,and nickel-metal hydride batter- ies( MH/Ni) with high output ,high energy densi- ty ,low cost and long durability are being consid- ered the alternative cardinal components for these vehicles .In recent years , synthesis of Ni(OH)2 powder with perfect high-temperature electrochem- ical properties has gotten more and more attention since the lowcharge acceptanc…     

Ammonia-Alkali Solution Coordination-Precipitation Route for Preparation of β-Ni(OH)2 Nano-Particles

在室温条件下,以NiCl2·6H2O,NH3·H2O和NaOH为原料,通过滴加氢氧化钠溶液到[Ni(NH3)6]2+配合物离子溶液中,经氢氧根离子取代氨分子与镍离子结合,实现可控合成氢氧化镍纳米晶粒。采用傅里叶变换红外光谱(FT-IR),综合热分析(TGA-DTG)仪,X射线衍射(XRD)仪和扫描电子显微镜(SEM)等测试技术对实验样品性质进行分析。结果表明:氨-碱均匀沉淀技术制备的样品为β-Ni(OH)2,平均粒径约为100 nm,且β-Ni(OH)2含有较多的镍成分和很少的层间离子,有利于提高β-Ni(OH)2的电化学性质。     

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%.     

Effects of modification on performance of natural graphite coated by SiO2 for anode of lithium ion batteries

A stable silicon dioxide film was coated on the surface of natural graphite anode by sol-gel method with Si（OCH2CH3）4, and effects of modification on performance of natural graphite were investigated. The structure and properties of graphite samples were determined by X-ray diffi＇actometry（XRD）, scanning electron microscopy（SEM）, energy-dispersive X-ray spectroscopy（EDS） and electrochemical measurements. The modified graphite shows mainly the layer structure, and silicon dioxide film is amorphous. Compared with the pure natural graphite, the modified graphite exhibits the higher specific capacity of 366 mA-h/g. After 40 charge-discharge cycles, the capacity retention ratio of the modified graphite reaches 99.55%, while that of natural graphite is only 83.04%. The results indicate that the surface modification of natural graphite by SiO2 is effective for improving the electrochemical performance of the natural graphite anode for lithium ion batteries.     

Ni,C,Co对二次电池用Ni（OH）2正极性能的影响

研究了泡沫式Ｎｉ（ＯＨ）２电极中不同活性物质及各种作用的添加剂Ｎｉ，Ｃ，Ｃｏ对电极的比容量和放电电压平台的影响。     

Application of spherical Ni（OH）2/CNTs composite electrode in asymmetric supercapacitor

1 Introduction Electrochemical capacitors (hereafter ECs) have greater power density than usual batteries and can be deeply discharged without any deleterious effect on life time[1]. Activated carbon(AC) with various modifications is the electrode materia…     

Al代α-Ni（OH）2的结构与电化学性能

采用化学共沉积法制备了Al代α-Ni(OH)2并对其结构和电化学性能进行了研究。采用XRD，IR，SEM和TGA等方法研究了其结构特征和热稳定性，采用循环伏安法研究了所制备的α-Ni(OH)2的电化学性能。结果表明：采用25mol％的Al取代的方法得到的晶体结构为α-Ni(OH)2，且试样可以在碱性溶液中稳定存在。与β-Ni(OH)2相比，其具有较大的扩散系数，电极反应受扩散控制。     

氨碱液相均匀沉淀技术制备β-Ni(OH)_2纳米颗粒（英文）

在室温条件下,以NiCl2·6H2O,NH3·H2O和NaOH为原料,通过滴加氢氧化钠溶液到[Ni(NH3)6]2+配合物离子溶液中,经氢氧根离子取代氨分子与镍离子结合,实现可控合成氢氧化镍纳米晶粒。采用傅里叶变换红外光谱(FT-IR),综合热分析(TGA-DTG)仪,X射线衍射(XRD)仪和扫描电子显微镜(SEM)等测试技术对实验样品性质进行分析。结果表明:氨-碱均匀沉淀技术制备的样品为β-Ni(OH)2,平均粒径约为100 nm,且β-Ni(OH)2含有较多的镍成分和很少的层间离子,有利于提高β-Ni(OH)2的电化学性质。     

表面包覆改善球形Ni（OH）2高温性能的研究

采用Yb／Co氢氧化物共沉淀包覆方法和Ca3（PO4）2与Co（OH）2分别沉淀分层包覆方法在球形Ni（OH）2的表面进行了均匀的包覆。前者利用COSO4，YbCl3和NaOH溶液进行共沉淀包覆，后者是先在球形Ni（OH）2的表面沉淀包覆Ca3（PO4）2，然后再沉淀包覆Co（OH）2。结果显示，两种包覆方法均能有效地提高球形Ni（OH）2的高温（60℃）性能。按照Yb／Co=0．75％：2％共沉淀包覆的试样制成AA型电池后，在60℃下1C放电的容量保持率达到常温下的90％。而2％Ca3（P04）2与2％Co（OH）2分层包覆后的球形Ni（OH）2制成AA型电池后，在60℃下1C放电的容量保持率达到常温下的81％。未包覆和仅用Co（OH）2包覆的球形Ni（OH）2制成的AA型电池，在60℃下1C放电的容量保持率分别只有46％和48％。通过循环伏安测试表明，利用表面包覆的方法可以增大正极材料Ni（OH）2在高温下的氧化电位、析氧电位和两者之间的电位差，从而提高了材料在高温下的电化学性能。     

Effects of pH value of reaction solution on structure and electrochemical performance of calcium-containing active material of secondary zinc electrodes

The calcium-containing active material of secondary alkaline zinc electrodes was prepared by a chemical coprecipitation method and characterized by scanning electron microscopy(SEM) and X-ray diffractometry(XRD).Their electrochemical performance was tested by the Galvanstatic charge-discharge method. The experimental results show that the sample synthesized at pH: 11. 15 has a typical calcium zincate crystal. The zinc electrode using this sample as active material shows higher discharge capacity, more negative discharge plateau potential and longer cycle lifetime.     

Influence of addition of Cu（OH）2 to KOH alkaline electrolyte on electrochemical properties of La2Mg0.9Al0.1Ni7.5Co1.5 hydrogen storage alloy electrode

The influence of the addition of Cu（OH）2 to 6 mol/L KOH alkaline electrolyte on the electrochemical properties of La2Mg0.9Al0.1Ni7.5Co1.5 hydrogen storage alloy electrode was investigated by electron probe X-ray microanalysis（EPMA）, X-ray diffraction（XRD） and electrochemical measurements. EPMA micrographs and XRD patterns show that the surface of the hydride electrode is plated by metal copper film. The thickness and compactness of Cu film increase with the increment of charge-discharge cycle number. The copper film of the hydride electrode surface can keep the hydrogen storage alloy particle in the electrode interior from oxidizing availably. The addition of Cu（OH）2 to alkaline electrolyte lowers the activation property and the high rate dischargeability of the La2Mg0.9Al0.1Ni7.5Co1.5 hydride electrode, but has no negative effect on the maximum discharge capacity of the hydride electrode. Moreover, it is effective to improve the cyclic stability of the hydride electrode utilizing electrodeposit Cu film on theLa2Mg0.9Al0.1Ni7.5Co1.5 hydride electrodes surface.     

钴的添加方式对α-Ni（OH）2电化学性能的影响

采用化学共沉淀法制备了可以在强碱性溶液中稳定存在的α—Ni（OH）2，比较了物理添加Co粉、晶格掺杂Co^2＋以及表面包覆Co（OH）2等Co的不同添加方式对α-Ni（OH）2电化学性能的影响。利用X射线衍射（XRD）对电极循环过程中的结构变化进行了表征，采用恒流充放电测试方法研究了所制备的α-Ni（OH）2在不同电流密度下的放电比容量。结果表明3种方式添加Co都可以在一定程度上提高样品的循环稳定性和大电流放电比容量，其中以表面包覆Co（OH）2的方式效果最为明显。     

不同Al含量α-Ni（OH）2的制备及电化学性能研究

采用均相沉淀法制备了不同Al含量的α-Ni（OH）2，用XRD和FT-IR对其结构进行了表征，用热重分析方法测试了其热稳定性。并用恒流充放电方法研究了不同Al含量取代样品的电化学性能。结果表明：用均相沉淀法，在Al的添加量为5％～20％（摩尔分数，下同）范围内均可制备得到稳定的α-Ni（OH）2：Al的添加量为0时，制备得到的样品为与α-Ni（OH）2相结构相同的碱式盐。ICP结果表明Al的添加量与产品中Al的实际含量之间有较大差别，且这种差别随Al的添加量的减小而增加。随着Al的添加量降低，样品中实际Al含量也降低，样品的放电比容量先升高，后降低；充电电压先降低后升高，而放龟电压开始变化很小然后迅速下降。当Al的添加量为5％～20％时，样品经过50次循环后衍射峰向高衍射角方向偏移，但仍保持α-Ni（OH）2相结构。而Al的添加量为0时，经过50次循环后转化为α-Ni（OH）2，但α相结构受到很大破坏。     

Preparation and properties of superfine Mg（OH）2 flame retardant

1 Introduction With the fast development of the macromolecule industry,the macromolecule synthetic materials such as plastic, synthetic rubber and synthetic fibre are used in a wide range of fields of building materials, household appliances, plane and au…     

Effect of Ti content on the hydrogen storage properties of Zr_（1-x）Ti_xMn_2Ce_（0.015） 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.