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electrochemical MEASUREMENT OF FLOW PARAMETERS IN DILUTE SOLUTION

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Chinese Journal of Chemical Engineering 1997年第3期5卷 38-47页

作者：王德耕朱士亮 Department of Chemical Engineering Zhengzhou Institute of Technology

A new theoretical method is proposed in the electrochemical measurement to obtain therelationship between flow parameter and the electrode current under the existence of ion migration ef-fect.In this way the measurement of local mass transfer coefficient,wall shear stress and liquid veloc-ity are presented and the experiment results are also described.

关键词： electrochemical measurement ionic migration mass transfer

electrochemical hydrogen storage behaviors of as-cast and spun RE-Mg-Ni-Co-Al-based AB2-type alloys applied to Ni-MH battery

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Rare Metals 2020年第2期39卷 181-192页

作者： Yang-Huan Zhang Gang Huang Ze-Ming Yuan Shi-Hai Guo Yan Qi Dong-Liang Zhao Key Laboratory of Integrated Exploitation of Baiyun Obo MultiMetal Resources Inner Mongolia University of Science and TechnologyBaotou014010China Department of Functional Material Research Central Iron and Steel Research InstituteBeijing100081China

Preparation of La-Mg-Ni-Co-Al-based AB2-type alloys La0.8-xCe0.2YxMgNi3.4Co0.4Al0.1(x=0,0.05,0.10,0.15,0.20)was performed using melt spinning technology.The influences of spun rate and Y content on structures and electrochemical hydrogen storage characteristics were studied.The base phase LaMgNi4 and the lesser phase LaNis were detected by X-ray diffraction(XRD)and scanning electron microscope(SEM).The variations of spinning rate and Y content cause an obvious change in phase content,but without altering phase composition,namely,with spinning rate and Y content growing,LaMgNi4 phase content augments while LaNi5 content declines.Furthermore,melt spinning and the replacing La by Y refine the grains dramatically.The electrochemical tests show a favorable activation capability of the two kinds of alloys,and the maximum discharge capacities are achieved during the first cycle.Discharge capacity firstly increases and subsequently decreases with spinning rate rising,while cycle stability is ameliorated and discharge capacity decreases with Y addition increasing.It is found that the amelioration of cycle stability is due to the enhancement of anti-pulverization,anti-corrosion and antioxidation abilities by both replacement of La with Y and melt spinning.Moreover,with the increase of Y addition and/or spinning rate,the electrochemical kinetics that contain charge transfer rate,limiting current density(IL),hydrogen diffusion coefficient(D)and the high rate discharge ability(HRD)firstly augment and then reduce.

关键词： electrochemical characteristic AB2-type alloy Y substitution Melt spinning

electrochemical characterization of AlPO_(4) coated LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2) cathode materials for high temperature lithium battery application

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Rare Metals 2021年第1期40卷 78-83页

作者： Jian-Hua Wang Yu Wang Yu-Zhong Guo Chang-Wei Liu Lu-Lu Dan Research Center for Analysis and Measure Kunming University of Science and TechnologyKunming 650093China School of Material Science and Engineering Kunming University of Science and TechnologyKunming 650093China

Aluminum phosphate(AlPO_(4))was used to modify the surface of LiNi_(1/3)Co_(1/3)Mn_(1/3)O_(2)(NCM)cathode material.The surface structure and electrochemical properties of the coated materials were investigated by X-ray photoelectron spectroscopy(XPS)and electrochemical impedance spectroscopy(EIS).The results confirm the formation of aluminum-containing solid solution on the surface of NCM particles.An aluminum phosphate coating blocks the Li+insertion-extraction process in cells charged at high rates at room temperature,increasing surface film resistance and decreasing discharge capacity.However,an aluminum phosphate aids the formation of a stable solid electrolyte interface film on NCM surface and stabilizes the Rct of cell as samples electrochemically cycled at 55℃.The electrochemical studies suggest that the initial columbic efficiency is significantly enhanced.An NCM sample coated with 1.0 wt%AlPO_(4) delivers a higher discharge capacity and shows excellent capacity retention ability.

关键词： Surface Lithium battery electrochemical

electrochemical process of sulfur in carbon materials from electrode thickness to interlayer

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Journal of Energy Chemistry 2019年第4期28卷 119-124页

作者： Xiaonan Tang Zhenhua Sun Huicong Yang Haitao Fang Fei Wei Hui-Ming Cheng Shuping Zhuo Feng Li School of Chemical Engineering Shandong University of Technology Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China School of Materials Science and Engineering Harbin Institute of Technology Department of Chemical Engineering Tsinghua University Tsinghua-Berkeley Shenzhen Institute Tsinghua University

Lots of efforts have been done on different porous carbon materials as cathode for Lithium–sulfur(Li–S)battery. However, seldom researches have been done on the relationship between cathode thickness and electrochemical performance. Our work investigates the relation between electrochemical performance and cathode thickness with typical porous carbon materials. We explain the phenomenon that only a modest cathode thickness can have the most adequate electrochemical reaction trend through the aspect of thermodynamics(chemical potential) so that the best electrochemical performance can be obtained.Besides, interlayer can remit the shuttle effect but hinder the lithium ion diffusion process simultaneously. And we verify the effect of interlayer thickness on the shuttle effect and lithium ion diffusion process.

关键词： Lithium-sulfur battery electrochemical reaction Cathode thickness Chemical potential Ion diffusion

electrochemical trepanning with uniform electrolyte flow around the entire blade profile

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Chinese Journal of Aeronautics 2019年第7期32卷 1748-1755页

作者： Dong ZHU Tingyu XUE Xingyan HU Zhouzhi GU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics

In the traditional machining process for diffusers, blades are easily deformed, and methods suffer from high tool wear and low efficiency. electrochemical machining(ECM) possesses unique advantages when applied to these difficult-to-machine materials. In the ECM process, theflow field plays a crucial role. Here, an electrolyte flow mode that supplies uniform flow around the entire blade profile was adopted for electrochemical trepanning of diffusers. Various flow rates were employed to obtain the optimal flow field. Simulations were conducted using ANSYS software, and results indicated that increasing the flow rate substantially afforded a more uniform flowfield. A series of experiments was then performed, and results revealed that increasing the flow rate greatly improved both the machining efficiency and the surface quality of the diffusers. The maximum feeding rate of the cathode reached 4 mm/min, the blade taper of the concave part decreased to 0.02, and the blade roughness was reduced to 1.216 lm. The results of this study demonstrated the high feasibility of this method and its potential for machining other complex components for engineering applications.

关键词： Diffuser electrochemical machining Flow Roughness Taper

electrochemical Radical Borylation of Aryl Iodides

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Chinese Journal of Chemistry 2019年第4期37卷 347-351,I0002页

作者： Junting Hong Qianyi Liu Feng Li Guangcan Bai Guoquan Liu Man Li Onkar S.Nayal Xuefeng Fu Fanyang Mo Department of Energy and Resources Engineering College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Natural and Biomimetic Drugs School of Pharmaceutical SciencesPeking UniversityBeijing 100871China Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China Jiangsu Donghai Silicon Industry S&T Innovation Center Jiangsu Weiming Environmental Protection S&T Co.Ltd.No.38Guangming RdDonghai CountyJiangsu 222300China

Herein,we report the first electrochemical strategy for the borylation of aryl iodides via a radical pathway using current as a driving force.A mild reaction condition allows an assorted range of readily available aryl iodides to be proficiently converted into synthetically valuable arylboronic esters under transition metal catalyst-free conditions.Moreover,this method also shows good functional group tolerance.Initial control mechanistic experiments reveal the formation of aryl radical as a key intermediate and the current plays an important role in the generation of radical intermediate.

关键词： electrochemical Radical Borylation Aryl Iodides proficiently converted

electrochemical investigation of copper chemical mechanical planarization in alkaline slurry without an inhibitor

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Journal of Semiconductors 2014年第2期35卷 141-146页

作者：王傲尘王胜利刘玉岭李炎 Institute of Microelectronics Hebei University of Technology

This work investigates the static corrosion and removal rates of copper as functions of H202 and FA/OIIconcentration, and uses DC electrochemical measurements such as open circuit potential （OCP）, Tafel ana- lysis, as well as cyclic voltammetry （CV） to study HaOa and FA/OIIdependent surface reactions of Cu coupon electrode in alkaline slurry without an inhibitor. An atomic force microscopy （AFM） technique is also used to measure the surface roughness and surface morphology of copper in static corrosion and polishing conditions. It is shown that 0.5 vol.% H202 should be the primary choice to achieve high material removal rate. The electro- chemical results reveal that the addition of FA/O II can dissolve partial oxide film to accelerate the electrochemical anodic reactions and make the oxide layer porous, so that the structurally weak oxide film can be easily removed by mechanical abrasion. The variation of surface roughness and morphology of copper under static conditions is consistent with and provides further support for the reaction mechanisms proposed in the context of DC electro- chemical measurements. In addition, in the presence of H202, 3 vol.% FA/O II may be significantly effective from a surface roughness perspective to obtain a relatively flat copper surface in chemical mechanical planarization （CMP） process.

关键词： alkaline slurry electrochemical copper CMP surface roughness

electrochemical performance of carbon nanotube-modified LiFePO_4 cathodes for Li-ion batteries

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Transactions of Nonferrous Metals Society of China 2010年第4期20卷 614-618页

作者：陈召勇朱华丽朱伟张建利李奇峰 College of Physics and Electronic Science Changsha University of Science and Technology

Carbon nanotubes (CNTs) and acetylene black (AB) were dispersed synchronously or separately between LiFePO4 (LFP) particles as conducting agents during the course of manufacture of LiFePO4 cathodes. The morphology and electrochemical performances of as-prepared LiFePO4 were evaluated by means of transmission electron microscopy (TEM), charge-discharge test, electrochemical impedance spectroscope (EIS) and cyclic voltammetry (CV). CNTs contribute to the interconnection of the isolated LiFePO4 or carbon particles. For the CNTs-modified LiFePO4, it exhibits excellent performance in terms of both specific capacity and cycle life. The initial discharge capacity is 147.9 mA·h/g at 0.2C rate and 134.2 mA·h/g at 1C rate, keeping a capacity retention ratio of 97% after 50 cycles. The results from EIS indicate that the impedance value of the solid electrolyte interface decreases. The cyclic voltammetric peak profiles is more symmetric and spiculate and there are fewer peaks. CNTs are promising conductive additives candidate for high-power Li-ion batteries.

关键词： LiFePO4 carbon nanotubes cyclic voltammetry (CV) electrochemical impedance spectroscopy (EIS) Li-ion batteries

electrochemical synthesis of 3-azido-indolines from amino-azidation of alkenes

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Chinese Chemical Letters 2021年第3期32卷 1033-1036页

作者： Shengping Guo Liyan Liu Kangfei Hu Qi Sun Zhenggen Zha Yu Yang Zhiyong Wang Hefei National Laboratory for Physical Sciences at Microscale CAS Key Laboratory of Soft Matter Chemistry&Center for Excellence in Molecular Synthesis of Chinese Academy of SciencesCollaborative Innovation Center of Suzhou Nano Science and Technology&School of Chemistry and Materials ScienceUniversity of Science and Technology of ChinaHefei 230026China School of Chemistry and Chemical Engineering Hefei Normol UniversityHefei 230601China

An electrochemical amino-azidation of 2-aminostyre ne with sodium azide(NaN3)was developed,which can be carried out smoothly in water under metal-free condition,affording a series of 3-azido indolines with high yields.

关键词： electrochemical Amino-azidation 2-Amino styrene Metal-free Oxidant-free 3-Azido indolines