含镓、锡的铝合金在碱性溶液中的阳极行为

铝的电极电位负,为一1．66V（VS．SHE）,电化当量高（298Ah／g）是一种理想的阳板材料．但是由于铝在空气和水中表面形成一层致密的氧化膜,使其在中性溶液中处于钝化状态．而在酸性或碱性溶液中铝表面氧化膜就会被溶解破坏,与水直接反应,腐蚀中途难以中止．这一直是影响铝作为阳板材料应用和深入研究的障碍,特别是对铝阳极活化溶解机理的研究进展缓慢．虽然目前人们在铝中添加Ga、In、11、Zn、Sn、Mg、Hg等元素,研制出各种铝合金阳极,提高了铝阳极活化性能,但是这些研究本质上仍属于经验性的．到1983年Despic等人提出了“场…     

硫酸根离子对铁在弱碱性溶液中阳极溶解和钝化行为的影响

采用浸泡实验, 电化学测试和表面分析技术研究了硫酸根离子浓度对铁在稀碳酸氢钠溶液中开路状态和阳极极化行为的影响. 在无硫酸根离子及含有少量硫酸根离子的碳酸氢钠溶液中, 铁的开路电位约为(-0.225±0.005) V, 并呈现钝化状态, 其电化学阻抗很大, 腐蚀速率较低. 在含有较高浓度硫酸根离子的碳酸氢钠溶液中, 铁的开路电位为(-0.790±0.010) V并呈现活性溶解状态, 其电化学阻抗较小, 腐蚀速率较高, 同时阳极极化曲线上能观察到活化-钝化转变现象. 由于铁在含有较高浓度硫酸根离子的碳酸氢钠溶液中处于活化状态, 阳极极化曲线上存在数个电流峰. 足够高的硫酸根离子浓度会导致铁表面预先形成或转变而成的氧化膜失效. 相比于自然曝氧状态, 在除氧条件下较低的硫酸根离子浓度即可引起铁在碳酸氢钠溶液中由钝态向活性溶解态的转变.     

不同阳极电位下铝青铜的电化学阻抗谱研究

应用电化学阻抗谱(EIS)方法研究了铝青铜的腐蚀溶解机制.结果表明,在活性溶解区,铝青铜以氯化络合物的形式溶解,并且CuCl2的扩散是该溶解过程的控制步骤;而在过渡区,铝青铜的EIS谱出现第2个容抗弧,这是由于CuCl络合物和氧化腐蚀产物在电极表面沉积成膜所致;在极限电流区,腐蚀产物膜产生破损点,导致电极表面快速溶解,产生严重的点蚀,这就是在该区域极化电位下EIS出现感抗弧的原因.     

稀土元素对二次锂电池中Li—Al负极材料电化学行为的影响

用纯锂作二次锂电池的负板材料有形成锂枝晶和钝化膜的缺点,采用在铝或其他金属如钙、镁、锡上欠电位沉积锂形成锂合金代替纯锂,对克服上述缺点有一定效果.本文报导了以稀土铝合金代替纯铝作基底欠电位沉积锂,在LiClO_4/碳酸丙烯酯电解液中稀土对改进电极性能有有益的影响.     

酸性AlCl3-BMIC离子液体中的铝阳极溶解

采用线性扫描伏安法研究了Lewis 酸性AlCl₃-BMIC (BMIC: 1-butyl-3-methylimidazolium chloride)离子液体中铝电极的溶解. 铝电极在阳极极化时出现了钝化现象, 钝化是由于在铝电极表面形成了固体AlCl₃钝化膜造成的. 铝的电化学溶解过程可以依次分为三个区: 电化学控制区、过渡区和钝化区. 在电化学控制区, 铝的电化学溶解速率随着电位的正移而逐渐增加; 在过渡区, 由于电极表面AlCl₄^-和Al₂Cl₇^-浓度发生改变而析出固体AlCl₃使得铝电化学溶解速率随着电位的正移而逐渐减小; 当钝化膜形成之后, 铝的电化学溶解速率不再随着电位的正移而发生改变, 铝溶解进入钝化区. 增加搅拌、升高温度、降低离子液体AlCl₃摩尔分数都可以增加铝溶解阳极极限电流密度.     

铝作阳极电解氢氧化钠溶液的实验研究

铝是活泼金属,作为阳极电解氢氧化钠溶液理论上应该是铝失去电子成为铝离子溶解于氢氧化钠溶液。通过实验研究,可以得出铝作阳极电解氢氧化钠溶液实质是电解水。电解产生的氧气可以在铝电极表面形成一层不致密的氧化铝,所生成的氧化铝不溶于氢氧化钠溶液。     

铝合金阳极氧化膜上交流电沉积制备含铈复合膜

通过交流电解沉积的方法在铝合金阳极氧化膜上制备了稀土铈复合膜, 并考察了氧化膜的厚度对形成复合膜的影响. 电解成膜溶液为含1 g · L-1 CeCl3 · 7H2O和10 mL · L-1 H2O2的水溶液, 正弦交流电的平均电压为10 V, 交流沉积的时间为5 min. 结果表明, 阳极氧化膜的厚度是影响成膜的主要因素, 在实验中, 氧化膜的厚度大于6.8 μm时才能形成连续均匀的复合膜. 测试分析结果表明, 复合膜表面的铈元素分布均匀, 平均含量为1.70%(质量分数);Ce元素主要分布在氧化膜多孔层的表层, 分布深度约1.5 μm.     

移动氢源用铝合金制氢技术研究

铝具有资源丰富、价格低廉、易保存、水解产氢量大(1244mLg-1)等特点,是NaBH4水解产氢的理想替代品[1].本文用机械球磨法制备了系列铝合金,并对其与水反应产氢的性能进行了研究.结果表明:锡和铋能提高铝的活性,其与铝形成的合金能在常温下与水反应.但铝锡合金在常温下与水反应速度缓慢,而铝铋合金能与水迅速反应,产氢率可达80%.     

以次磷酸钠为还原剂化学镀铜的电化学研究

通过电化学方法研究了以次磷酸钠为还原剂, 柠檬酸钠为络合剂的化学镀铜体系. 应用线性扫描伏安法, 检测了温度、pH值、镍离子含量对次磷酸钠阳极氧化和铜离子阴极还原的影响. 结果表明, 升高温度能够加速阳极氧化与阴极还原过程; pH值的提高可促进次磷酸钠氧化, 但抑制铜离子还原; 镍离子的存在不仅对次磷酸钠的氧化有强烈的催化作用, 而且与铜共沉积形成合金. 该合金有催化活性, 使化学镀铜反应得以持续进行.     

多孔质铝阳极氧化膜表面与界面研究

铝质材料阳极氧化作为铝质材料最重要的表面改性技术已有几十年历程，并在现代工业中获得了广泛应用［1，’］．前人对铝阳极氧化股的结构、组成及生成机理等进行了大量的研究工作［3－6］，研究结果表明铝阳极氧化膜具有多孔型和壁垒型二种，其中多孔型铝阳极氧化膜是由非晶态     

The study on microstructure and electrochemical properties of Al–Mg–Sn–Ga–Pb alloy anode material for Al/AgO battery

The microstructure of Al–Mg–Sn–Ga–Pb quinary aluminum alloy anode material and the influences of its electrochemical properties and self-corrosion rate in 4 mol/l NaOH +10 g/l Na₂SnO₃ medium were studied. The microstructure and morphology were characterized by metallographic microscope, transmission electron microscope, and scanning electron microscopy. The electrochemical properties were tested by electrochemical workstation, and the self-corrosion rate of Al alloy anode was studied by methods of recovery H₂ gas by discharge water. The results show that homogenization has not much impact on the electrochemical properties and the corrosion rate of the cast aluminum alloy anode material; besides, return annealing treatment of the cold-rolled Al–Mg–Sn–Ga–Pb quinary aluminum alloy anode material can reduce the rate of self-corrosion and make Al anodic potential shift negative steadily and improve the properties of the material.

     

Anodic polarization of Al-Sn alloy in H3PO4 solutions

The anodic polarization behaviour of Al-Sn alloy (5.6% Sn) was studied in aerated 1, 1.5 and 2 M H₃PO₄ acid solutions using potentiodynamic and potentiostatic techniques. Anodic behaviour of Al and Sn metals was investigated for comparison. The results show that the alloy exhibits active-passive transition behaviour. The passivation of the examined alloy is due to the formation of oxide film for both Al and Sn incorporated with their phosphates. In general, at constant concentration of PO₄ ³⁻ ion, the passive current density (I _pass) is decreased with increase of pH in the range 2.5–5. Further, the influence of Cl⁻ ions on the passivity of the given alloy was studied. It was found that the aggressive effect of Cl⁻ ions on the passive film is inhibited with increase in phosphate concentration and pH. However, the addition of organic compounds (2- and 3-picoline and 2-aminopyridine) shows that only 2-aminopyridine inhibited the attack of Cl⁻ ions. Received: 24 October 1997 / Accepted: 5 February 1998     

Anodic film formation on binary Al?Mg and Al?Ti alloys in nitric acid

Nitric acid is commonly used for surface treatments of aluminium alloys. It is used to clean the surfaces after alkaline etching; it has application in chemical polishing and is also used for electrograining. The majority of these treatments undergo the application of anodic polarisation that results in formation of anodic oxide film. However, little is known about the behaviour of aluminium containing magnesium or titanium in solid solution under such conditions. To reveal the effects of magnesium and titanium alloying additions on anodic film formation in nitric acid, Al‐1800 ppm Mg and Al‐800 ppm Ti alloys were investigated. It was found that porous alumina film developed on the surfaces with reduced efficiency of 40%, due to the reactive nature of nitric acid to alumina. The presence of magnesium and titanium in aluminium had little influence on the efficiency of film growth, as confirmed by the relatively similar thicknesses of oxide formed on binary alloys and aluminium. However, incorporation of magnesium ions into the alumina film led to development of a high‐population density of localised voids near the alloy/film interface. An increased titanium content was found in the film regions close to the alloy/film interface, indicating its oxidation. Copyright © 2009 John Wiley & Sons, Ltd.     

Investigation of immiscible alloy system of Al–Sn thin films as anodes for lithium ion batteries

The Al–Sn, which is immiscible alloy, film was prepared by e-beam deposition to explore the possibility as anode material for lithium ion batteries for the first time. The film has a complex structure with tiny Sn particles dispersed homogeneously in the Al active matrix. The diffusion coefficients of Li⁺ in these Al–Sn alloy films were determined to be 2.1–3.2 × 10⁻⁸ cm²/s by linear sweep voltammetry. The film electrode with high Al content (Al–33wt%Sn) delivered a high initial discharge capacity of 972.8 mA h g⁻¹, while the film electrode with high Sn content (Al–64wt%Sn) with an initial discharge capacity of 552 mA h g⁻¹ showed good cycle performance indicated by retaining a capacity of about 381 mA h g⁻¹ after 60 cycles. Our preliminary results demonstrate that Al–Sn immiscible alloy is a potential candidate for anodic material of lithium ion batteries.     

Effects of solid polymer electrolyte coating on the composition and morphology of the solid electrolyte interphase on Sn anodes

In order to discuss the effect of polymer coating layer on the Sn anode, the composition and morphology of the solid electrolyte interphase (SEI) film on the surface of Sn and Sn@PEO anode materials have been investigated. Compared with the bare cycled Sn electrode, the SEI on the surface of cycled Sn@PEO electrode is thinner, smoother, and more stable. Therefore, the Sn@PEO nanoparticles can basically keep the original appearance during cycling. Based on the results obtained from X-ray photoelectron spectroscopy (XPS), the SEI formed on the Sn@PEO electrode is characterized by inorganic components (Li₂CO₃)-rich outer layer and organic components-rich inner which could make the SEI more stable and inhibit the electrolyte immerging into the active materials. In particular, the elastic ion-conductive polyethylene oxide (PEO) coating could increase the toughness of SEI and allow the SEI to endure the stress variation in repetitive lithium insertion and extraction process. As a result, the Sn@PEO electrodes show significantly better capacity retention than bare Sn electrodes. The findings can serve as the theoretical foundation for the design of lithium-ion battery electrode with high energy density and long cycle life.     

无锡钢电镀溶液中氟离子电化学行为的研究

采用交流伏安法、电化学阻抗谱(EIS)和Mott-Schottky 分析技术研究了无锡钢电镀液中氟离子电化学行为. 结果表明, 在氧化还原过程中氟离子抑制铬离子化学状态转变, 降低铅合金和铅氧化物阳极的氧化电流密度, 改变铅合金和铅氧化物阳极的氧化还原历程. EIS 结果表明电场作用下溶液中铬氧离子团发生聚合, 在铅合金阳极表面形成感抗现象. 含氟溶液中铬氧离子团在阳极表面的感抗现象消失, 溶液导电性提高. Mott-Schottky 曲线显示氟离子提高阳极材料的载流子密度, 铅合金阳极和铅氧化物阳极均为n 型半导体.     

Effects of current densities on the formation of LiCoO<Subscript>2</Subscript>/graphite lithium ion battery

The activation characteristics and the effects of current densities on the formation of a separate LiCoO₂ and graphite electrode were investigated and the behavior also was compared with that of the full LiCoO₂/graphite batteries using various electrochemical techniques. The results showed that the formation current densities obviously influenced the electrochemical impedance spectrum of Li/graphite, LiCoO₂/Li, and LiCoO₂/graphite cells. The electrolyte was reduced on the surface of graphite anode between 2.5 and 3.6 V to form a preliminary solid electrolyte interphase (SEI) film of anode during the formation of the LiCoO₂/graphite batteries. The electrolyte was oxidized from 3.95 V vs Li⁺/Li on the surface of LiCoO₂ to form a SEI film of cathode. A highly conducting SEI film could be formed gradually on the surface of graphite anode, whereas the SEI film of LiCoO₂ cathode had high resistance. The LiCoO₂ cathode could be activated completely at the first cycle, while the activation of the graphite anode needed several cycles. The columbic efficiency of the first cycle increased, but that of the second decreased with the increase in the formation current of LiCoO₂/graphite batteries. The formation current influenced the cycling performance of batteries, especially the high-temperature cycling performance. Therefore, the batteries should be activated with proper current densities to ensure an excellent formation of SEI film on the anode surface.     

Some novel binuclear group 13 metal tin hydrides formed in Ar matrices following the codeposition of the metal vapor with SnH4

IR measurements show that co-condensation of Al or Ga atoms (M) with SnH4 in a solid Ar matrix at about 12 K results mainly in the spontaneous insertion of the metal into an Sn-H bond to form the M(II) hydride HMSnH3. Simultaneously the Ga2 dimer also reacts with SnH4, possibly to form a nido-type cluster Ga2(mu-H)4Sn, with a metal-deficient cubane-like structure. All of these products are photolabile. Irradiation with visible light causes HMSnH3 to tautomerize to the novel dihydrido-bridged species H3M(mu-H)2Sn, which decomposes in turn under broad-band UV-visible light (lambda=200-800 nm); some H3Al(mu-H)2Sn is formed even on deposition. The data collected from experiments with SnH4 and SnD4 and different reagent concentrations, together with the results of quantum chemical calculations, are used to interpret the results and elucidate the structures and bonding of the new species.     

锂离子电池用SnZn/Cu薄膜负极材料的研究

合金型锂离子电池负极材料由于容量高、安全性好而备受关注. 采用磁控溅射法在铜箔上渡膜制备锡锌薄膜, 经热处理后得到合金薄膜电极. 薄膜热处理后, 表面活性层形成Cu3Sn中间合金. 合金薄膜是由尺寸在5 μm左右的合金颗粒构成, 而合金颗粒则由更小的尺寸在50 nm左右微粒组成, 该合金薄膜同时具有薄膜、中间合金和纳米结构材料的特征. 合金薄膜电极具有较高的充放电容量、良好的循环性能和非常高的充放电效率. 在0.01～1.0 V (vs. Li/Li＋)区间, 电极循环200周后放电容量保持在300 mAh&#8226;g－1以上, 与第一次脱锂容量相比较, 容量保持率高达91.9%, 充放电效率大于98.0%.