Al含量对AB5型储氢合金电极低温和高倍率性能的影响

系统地研究了Al含量对富Ce储氢合金MmNi_4-xCo_0.7Mn_0.3Al_x（x=0,0.1,0.2,0.3）电极综合电化学性能,尤其是对低温和高倍率性能的影响。在常温下,储氢合金电极放电容量和循环性能均随着Al含量的增加而增加,而高倍率放电性能严重下降。-20℃时,放电容量仍随着Al含量的增加而增加,但在-40℃下放电容量随之严重衰退。电化学动力学结果表明,常温下高Al合金高倍率性能的降低主要是由于电极表面电荷转移过程的恶化;低温-40℃下,Al同时降低了合金电极的表面电催化活性以及体相H扩散能力,严重恶化电极过程动力学,从而导致了高Al合金极低的容量及电压输出。考虑到各电极的综合电化学性能,MmNi_3.8Co_0.7Mn_0.3Al_0.2为最佳的成分配比。     

Al含量对AB5型储氢合金电极低温和高倍率性能的影响

系统地研究了Al含量对富Ce储氢合金MmNi_4-xCo_0.7Mn_0.3Al_x（x=0,0.1,0.2,0.3）电极综合电化学性能,尤其是对低温和高倍率性能的影响。在常温下,储氢合金电极放电容量和循环性能均随着Al含量的增加而增加,而高倍率放电性能严重下降。-20℃时,放电容量仍随着Al含量的增加而增加,但在-40℃下放电容量随之严重衰退。电化学动力学结果表明,常温下高Al合金高倍率性能的降低主要是由于电极表面电荷转移过程的恶化;低温-40℃下,Al同时降低了合金电极的表面电催化活性以及体相H扩散能力,严重恶化电极过程动力学,从而导致了高Al合金极低的容量及电压输出。考虑到各电极的综合电化学性能,MmNi_3.8Co_0.7Mn_0.3Al_0.2为最佳的成分配比。     

共吸附剂修饰TiO2薄膜电极

共吸附剂修饰纳晶TiO₂薄膜电极是目前染料敏化太阳电池研究的一个热点. 本文通过平带电势和电化学阻抗研究了二(3,3-二甲基丁基)次膦酸和鹅脱氧胆酸两种共吸附剂修饰对TiO₂薄膜电极的平带电势和电极表面钝化能力的影响及其在染料敏化太阳电池中的应用. 结果表明, 二(3,3-二甲基丁基)次膦酸能更有效地钝化TiO₂薄膜表面, 并使TiO₂薄膜平带电势负移. 电化学阻抗谱测试结果表明, 在染料敏化太阳电池中, 相对于鹅脱氧胆酸, 二(3,3-二甲基丁基)次膦酸能更显著地提高器件的电子寿命和开路电压.     

金属卟啉与Keggin型硅钨酸修饰电极的制备及电催化性能测定

运用自组装和电化学组装联用方法,将镍卟啉配合物THPPNi和Keggin型硅钨酸SiW₁₂修饰到玻碳电极上,制备镍卟啉修饰电极和镍卟啉/硅钨酸复合修饰电极,研究其在DMF溶液中的电化学行为,测定在碱性条件下对NO₂^-和BrO₃^-的电催化性能。循环伏安和交流阻抗研究结果表明,复合修饰电极THPPNi/SiW₁₂的电极过程属于扩散控制过程;复合修饰电极优于单一修饰金属卟啉和多酸修饰电极。     

Ti和Zr的取代对MgNi型储氢合金电极电化学性能的影响

使用机械合金化法成功地合成了镁基储氢合金MgNi, Mg_0.9Ti_0.1Ni,和Mg_0.9Ti_0.06Zr_0.04Ni，并对其结构和电化学性能进行了研究。X射线衍射（XRD）表明，这一系列合金的主相为非晶态，透射电镜（TEM）表明，Ti和Zr取代的合金的颗粒直径约为2~4 μm。Ti和Zr的取代提高了合金电极的循环寿命。50周充放电循环后， Mg_0.9Ti_0.06Zr_0.04Ni合金电极的放电容量高于MgNi合金电极91.74%，高于Mg_0.9Ti_0.1Ni合金电极37.96%。电极容量衰减的主要原因是在合金电极表面形成Mg的腐蚀产物Mg(OH)₂。动电位扫描结果显示，Ti和Zr的添加提高了合金电极在碱液中的抗腐蚀性能。交流阻抗(EIS)测试表明，适量Ti和Zr的添加可以明显提高合金电极的电催化活性。     

热处理对La4MgNi19储氢电极合金结构和性能的影响

以感应熔炼和不同的热处理工艺制备了La₄MgNi₁₉合金, 用X射线衍射(XRD)和电化学测试系统研究了该合金的相结构和电化学性能. 结构分析表明: 当热处理工艺为900 °C+水淬时, 合金主要由CaCu₅结构的LaNi₅相和少量未知相组成; 当热处理工艺为900 °C退火时, 合金主要由Pr₅Co₁₉、Ce₅Co₉结构的(La, Mg)₅Ni₁₉相及少量CaCu₅结构的LaNi₅相组成. 淬火和退火后合金的电化学循环稳定性(S₁₀₀)分别为49.7%及76.0%, 合金电极的电化学性能和相结构密切相关. 退火热处理有利于生成Pr₅Co₁₉、Ce₅Co₉型相. 在La-Mg-Ni 系储氢合金中, La₄MgNi₁₉合金电化学循环稳定性不及La₃MgNi₁₄合金.     

纳米氧化铜掺杂对储氢合金电极性能的影响

采用纳米氧化铜作为添加剂制备储氢合金电极, 考察了氧化铜对储氢合金电池储备容量的调节作用, 分析了掺杂后电极及电池质量的变化, 研究了掺杂合金电极的电化学性能, 并用SEM、EIS、CV等方法分析了反应的电化学机理. CV、SEM结果表明, 氧化铜在首次充电过程中被还原成低价态沉积在合金颗粒表面, 由于氧化铜比容量远大于合金, 可以通过掺杂氧化铜调节合金的储备容量. 电化学测试结果表明, 掺杂合金电极具有更好的高倍率充放电能力和循环性能. EIS分析结果表明, 掺杂合金电极导电性增强, 电化学活性提高.     

Mg0.9Ti0.1Ni1－xCox (x＝0.05, 0.1, 0.15, 0.2)合金的合成及电化学性能研究

采用机械合金化法合成了Mg_0.9Ti_0.1Ni_1－xCo_x (x＝0.05, 0.1, 0.15, 0.2)系列四元合金, 并对该系列合金的结构和电化学性能等方面进行了研究. 球磨100 h的该系列合金, XRD结果表明, X射线衍射峰均呈现宽化趋势, 基本呈非晶态. 充放电结果表明, 该系列合金具有较好的活化性能, 它们的循环稳定性明显好于MgNi合金, 其中Mg_0.9Ti_0.1Ni_0.8Co_0.2最大放电容量最高, 为427.5 mAh•g^－1. 在充放电循环过程中, Mg在合金表面形成了Mg(OH)₂是合金电极衰减的主要原因. 腐蚀曲线的测试结果表明, Co的添加可以提高合金电极在碱液中的抗腐蚀能力, 从而提高了电极的循环稳定性.     

Mg0.9Ti0.1Ni1－xCox (x＝0.05, 0.1, 0.15, 0.2)合金的合成及电化学性能研究

采用机械合金化法合成了Mg_0.9Ti_0.1Ni_1－xCo_x (x＝0.05, 0.1, 0.15, 0.2)系列四元合金, 并对该系列合金的结构和电化学性能等方面进行了研究. 球磨100 h的该系列合金, XRD结果表明, X射线衍射峰均呈现宽化趋势, 基本呈非晶态. 充放电结果表明, 该系列合金具有较好的活化性能, 它们的循环稳定性明显好于MgNi合金, 其中Mg_0.9Ti_0.1Ni_0.8Co_0.2最大放电容量最高, 为427.5 mAh•g^－1. 在充放电循环过程中, Mg在合金表面形成了Mg(OH)₂是合金电极衰减的主要原因. 腐蚀曲线的测试结果表明, Co的添加可以提高合金电极在碱液中的抗腐蚀能力, 从而提高了电极的循环稳定性.     

混合稀土对A2B7型储氢合金结构和电化学性能的影响

采用感应熔炼方法制备了A₂B₇型La_0.83-0.5x（Pr_0.1Nd_0.1Sm_0.1Gd_0.2）_xMg_0.17Ni_3.1Co_0.3Al_0.1（x=0~1.66）储氢合金,并在He+Ar气氛和 1 173 K下进行退火处理。通过X射线衍射（XRD）、扫描电子显微镜（SEM）和电化学方法,研究了混合稀土（Pr,Nd,Sm,Gd）替代La元素对合金物相结构和电化学性能的影响。合金相结构分析表明,混合稀土含量对合金组成和相结构有重要的影响,随混合稀土含量x的增加,合金中主相A₂B₇型（2H-Ce₂Ni₇型+3R-Gd₂Co₇型）相丰度逐渐增多,其中2H-Ce₂Ni₇型相丰度先增多后减少,3R-Gd₂Co₇型相丰度则逐渐增加,主相晶胞参数随x增加而减小。电化学结果表明,随混合稀土含量增加,放氢平台压逐渐升高,合金电极的最大放电容量和循环稳定性均呈先增大后减小的规律,其中x=0.4合金电极具有最高的电化学放电容量（389.8 mAh·g^-1）和最佳的循环寿命（S₁₀₀=91.30%）;合金电极的高倍率放电性能（HRD）则随x的增加获得显著提高。适量的混合稀土替代量可显著改善合金电极的综合电化学性能。     

LaNi5型储氢合金表面修饰及其电化学性能研究

0引言近年来,随着科学技术水平的提高和世界范围环保意识的增强,汽车尾气所造成的环境污染问题日益引起人们的重视[1]。电动汽车的发展可以有效制约燃油汽车所造成的环境污染。MH/Ni电池是一种无污染的“绿色能源”,它具有高比能量、高比功率、长寿命及安全性好等优异性能,非常     

铝合金表面改性对有机涂层附着力的影响及腐蚀防护性能研究

利用电化学阻抗（EIS）、扫描微参比技术（SRET）、接触角、粗糙度、附着力、盐雾等测试方法,研究了铝合金阳极氧化与贻贝黏附蛋白（MAP）/CeO₂/硅烷γ-APS（MCA）表面复合修饰的腐蚀防护性能以及对改性聚氨酯涂层附着力和耐蚀性的影响。结果表明,MCA复合膜可抑制铝合金的腐蚀,并具有一定的自修复功能;阳极氧化和MCA表面复合修饰可为铝合金提供有效的早期腐蚀防护作用,且能提高铝合金表面粗糙度和润湿性,显著提升改性聚氨酯涂层在铝合金表面的附着力和耐蚀性,因而结合改性聚氨酯涂层和表面复合修饰可实现对铝合金长期有效的腐蚀防护。     

Effect of Aluminum Alloy Surface Modification on Adhesion of the Modified Polyurethane Coating and Its Corrosion Protective Performance北大核心CSCD

The ordinary organic coatings on aluminum alloy usually encounter a problem of low adhesion to the substrate, which results in destruction and failure of the long-term protective performance of the anticorrosion systems. The surface modification of aluminum alloy is able to enhance the adhesion of organic coating on aluminum alloys, and to improve their protective performance. In this work, a combined surface modification of anodic oxidation and mussel adhesion protein/CeO2/3-aminopropyltriethoxysilane composite film (MCA) was developed on the aluminum alloy. The adhesion of modified polyurethane coated on the treated aluminum alloy and its corrosion protective performance were evaluated comprehensively by using contact angle, adhesion strength, electrochemical impedance spectroscopy (EIS), and scanning reference electrode technique (SRET). The measurements of EIS and SRET demonstrated that the MCA composite film on anodic oxidized Al possessed self-healing function and provided effective protection against early corrosion of aluminum alloy. The pull-off test showed that both anodic oxidation treatment and MCA composite film modification were able to increase the adhesion of modified polyurethane coating on aluminum alloy, and their combined action were supposed to remarkably enhance the adhesion strength up to 17.1 MPa. The reason for the improvement of adhesion was that the anodic oxidation treatment and MCA composite film modification could improve the surface roughness of aluminum alloy, and enhance the surface wettability and surface polarity, which is beneficent to enhance the bonding of the modified polyurethane coating to aluminum alloy surface. The EIS results showed that no any corrosion occurred for the modified polyurethane coating on the treated aluminum alloy during 65 d immersion in 3.5wt.% NaCl solution. The impedance value in low frequency range of the modified polyurethane coating always maintained at a high order of magnitude on the aluminum alloy treated by anodic oxidation and MCA composite film modification, showing an excellent protective performance of the coating system. The evaluation of Neutral Salt Spray (NSS) indicated that the modified polyurethane coating on the treated aluminum alloy owned superior corrosion protection performance, and the adhesion strength remained 13.1 MPa and no any corrosion was found at the scratch locations even after 1200 h of salt spray testing. It was concluded that combination of anodic oxidation and MCA composite film were capable of significantly improving the adhesion of modified polyurethane coating on aluminum alloy and providing long-term effective corrosion protection for aluminum alloy. © 2021 Authors. All rights reserved.     

Improved Electrochemical Kinetic Performances of La-Mg-Ni-based Hydrogen Storage Alloy Modified by Ni-Polypyrrole Complex Surface Treatment

In order to improve the electrochemical kinetic performances of La-Mg-Ni-based alloy, complex surface modification of Ni with excellent catalytic activity and conducting polymer polypyrrole(PPy) was performed via electroless plating method. FESEM images revealed that the complex Ni-PPy treatment resulted in more micropores at the alloy surface, with Ni particles and cotton fiber-shape PPy microspheres attached. Both the larger surface area induced by the micropore and the higher catalytic activity and conductivity on account of the dispersed Ni particles/PPy microspheres promoted the electrode reaction, thereby increasing the discharge capacity of the modified alloy electrode. Electrochemical impedance spectroscopy(EIS) and linear polarization results showed that the Ni-PPy treatment decreased the charge-transfer resistance and increased the exchange current density greatly, far more than the single-component Ni or PPy treatment. Consequently, a notable improvement in high rate dischargeability(HRD) was observed, and at a high discharge current density of 1800 mA/g, the HRD of the modified electrode increased by 10.4% compared with that of the bare electrode.     

硅片表面多金属污染的交流阻抗表征

在接近氢氟酸实际应用浓度条件下, 利用交流阻抗技术研究了硅片表面金属微观污染行为, 在氢氟酸溶液中分别加入0.5和1 mg/g的铜、铁、镍、钙四种金属离子, 获得了硅片在单金属溶液中的特征交流阻抗谱, 并在此基础上研究了三种金属及四种金属共存时的特征交流阻抗谱, 通过等效电路的拟合估算了硅/氢氟酸界面电化学反应的动力学参数, 并结合扫描电镜形貌图探讨了不同类型的单金属和多金属对硅电化学行为的影响. 结果表明, 多金属微观污染是各种单金属协同作用的结果, 铜在硅片上发生电化学沉积, 直接导致硅片表面粗糙化. 铁对硅片表面的破坏严重, 同时影响铜的沉积. 镍的存在使硅片表面更容易氧化. 而钙通过在硅片表面形成氟化钙沉淀物可以钝化表面, 减缓铜在硅片表面的沉积.     

Direct DNA Hybridization on the Single‐Walled Carbon Nanotubes Modified Sensors Detected by Voltammetry and Electrochemical Impedance Spectroscopy

Carboxylic acid functionalized single‐walled carbon nanotubes modified graphite sensors (SWCNT‐PGEs) were developed for electrochemical monitoring of direct DNA hybridization related to specific sequence of Hepatitis B virus, which substantially enhance the electrochemical transduction resulting from guanine oxidation signal comparison to bare PGEs. The performance characteristics of DNA hybridization on disposable CNT‐PGE were explored measuring the guanine signal in terms of optimum analytical conditions; probe and target concentration, hybridization time, and selectivity. The voltammetric results were also complemented with electrochemical impedance spectroscopy (EIS), that was used to characterize the successful construction of carbon nanotubes modification onto the surface of PGEs.     

Simultaneous quartz crystal microbalance-electrochemical impedance spectroscopy study on the adsorption of anti-human immunoglobulin G and its immunoreaction at nanomaterial-modified Au electrode surfaces.

The quartz crystal microbalance method (QCM), in combination with electrochemical impedance spectroscopy (EIS), has been utilized to monitor in situ anti-human IgG adsorption on several Au-based surfaces, bare Au, nanogold/4-aminothiophenol (4AT)/Au, and multi-walled carbon nanotubes (MWCNT)/Au, and succeeding human IgG reactions. Also, the immobilization protocol of anti-human IgG via its glutaraldehyde (GA) cross-linking with self-assembled 4AT on an Au electrode and the subsequent surface immunoreaction were examined. The resonant frequency (f(0)) and the motional resistance (R(1)) of the piezoelectric quartz crystal (PQC) as well as electrochemical impedance parameters were measured and discussed. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) of the ferricyanide/ferrocyanide couple were examined before and after electrode modification, the antibody adsorption and antibody-antigen reactions. We found that the amount for antibody adsorption was the greatest on the colloid Au modified surface, and that at MWCNT ranked the second, while specific bioactivity was almost identical on the four kinds of surfaces. Two parameters simultaneously obtained at the colloid Au modified surface, Deltaf(0) and DeltaC(s) (interfacial capacitance), have been used to estimate the association constant of the immunoreaction.     

泡沫铅对VRLA电池负极活性物质结构及性能影响

0引言随着36V/42V汽车电源系统的提出,新一轮汽车用电池的竞争不断加剧。从目前情况看,铅酸电池由于具有成本低廉,使用可靠,原材料来源丰富,铅回收率可高达98%等优点,因此成为电动车电源最实际的选择之一[1]。但作为电动车用电池,需要克服其比能量低、充电接受能力差和负极硫酸盐化等缺点。为此各国科学家开展了大量的研究工作。最近报道用铸造多孔体作为敞口铅酸电池的集流体,它的比表面积为14cm2·cm-3,正极活性物质利用率上升到50%,远高于传统的铸造板栅[2]。在铅酸电池集流体研究领域里另一个重大进步,就是以R V C(R etic-ulated V i…     

Corrosion resistance and durability of superhydrophobic surface formed on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution

The corrosion resistant performance and durability of the superhydrophobic surface on magnesium alloy coated with nanostructured cerium oxide film and fluoroalkylsilane molecules in corrosive NaCl aqueous solution were investigated using electrochemical and contact angle measurements. The durability of the superhydrophobic surface in corrosive 5 wt% NaCl aqueous solution was elucidated. The corrosion resistant performance of the superhydrophobic surface formed on magnesium alloy was estimated by electrochemical impedance spectroscopy (EIS) measurements. The EIS measurements and appropriate equivalent circuit models revealed that the superhydrophobic surface considerably improved the corrosion resistant performance of magnesium alloy AZ31. American Society for Testing and Materials (ASTM) standard D 3359-02 cross cut tape test was performed to investigate the adhesion of the superhydrophobic film to the magnesium alloy surface. The corrosion formation mechanism of the superhydrophobic surface formed on the magnesium alloy was also proposed.     

Stereoselective Interaction between DNA and Stable Chiral Surfaces Modified with 1,2‐Diphenylethylenediamine Enantiomers

This work described an interesting phenomenon of the stereoselective adsorption behaviors of DNA on stable chiral surfaces which were modified with 1,2‐diphenylethylenediamine enantiomers on gold electrodes. The modification process and electrochemical characterization of the chiral surfaces were measured by cyclic voltammetry (CV). The stereoselective adsorption behaviors of DNA on the two chiral surfaces were investigated via atomic force microscopy (AFM), CV, electrochemical impedance spectroscopy (EIS) and quartz crystal microbalance (QCM). All results confirmed that (1R,2R)‐1,2‐diphenylethylenediamine modified surface had stronger interaction with DNA molecules than (1S,2S)‐1,2‐diphenylethylenediamine modified surface, and the chirality of the surfaces created an different effect on the morphology and adsorption quantity of DNA.