Materials Chemistry Commons^™

Synthesis Of Lini0.5Co0.2Mn0.3O2 For Lithium Ion Batteries And The Mechanism Of Capacity Fading At High Temperature, Wen Liu, Miao Wang, Ji-Tao Chen, Xin-Xiang Zhang, Heng-Hui Zhou

Journal of Electrochemistry

The Ni-rich cathode materials, LiNi_0.5Co_0.2Mn_0.3O₂, have been synthesized by Co-precipitation and high-temperature solid-phase sintering method. Constant current charge-discharge tests showed high discharge capacity of 179.2 mAh·g^-1 in the 3.0~4.4 V at 0.2C. However, at 55 °C the LiNi_0.5Co_0.2Mn_0.3O₂ experienced the dramatic capacity fading after 100 charge-discharge cycles. Electrochemical Impedance Spectroscopy, X-Ray Photoelectron Spectroscopy, Atomic Emission Spectroscopy have been employed to study the capacity fading mechanism of LiNi_0.5Co_0.2Mn_0.3O₂ cycled at high temperature in range of high-voltage charge and …

Electrochemical Performances Of Carbon-Coated Na2Ti6O13 Nanotubes, Guo-Ran Li, Shuai Sun, Xue-Ping Gao

Journal of Electrochemistry

With rutile TiO₂ and NaOH as starting materials, the Na₂Ti₆O₁₃ nanotubes were prepared by a hydrothermal reaction. The carbon-coated Na₂Ti₆O₁₃ nanotubes were obtained by treating the Na₂Ti₆O₁₃ nanotubes for 4 h in glucose aqueous solutions containing 0.1 mol·L^-1 NaOH. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microcopy (TEM). The results showed that the dimensions of carbon-coated Na₂Ti₆O₁₃ nanotubes were 14 ~ 19 nm of outer diameter, 2 ~ 5 …

Synthesis And Electrochemical Properties Of Yttrium-Doped Lini0.49Mn1.49Y0.02O4, Xian-Wen Zhang, Zheng-Xi Zhang, Li Yang, Shao-Hua Fang, Long Qu

Journal of Electrochemistry

The LiNi_0.49Mn_1.49Y_0.02O₄ cathode material was synthesized using the citric acid-assisted sol-gel method by partial substitutions of Ni and Mn with Y in the LiNi_0.5Mn_1.5O₄ material. The influences of Y doping on the structure and electrochemical properties were investigated by means of X-ray diffraction, cyclic voltammetry, galvanostatic charge/discharge tests and AC impedance spectroscopy. The results showed that the introduction of Y into the LiNi_0.5Mn_1.5O₄ greatly improved the cycle performance and rate capability. When the charge and discharge current was 1 C in the potential …

Template-Free Synthesis Of Porous Nio Hierarchical Structure For High Performance Supercapacitors, Yun Huang, Zhong Wu, Xin-Bo Zhang

Journal of Electrochemistry

A facile and template-free hydrothermal method is proposed to successfully synthesize porous NiO hierarchical structure, which is found to be assembled from ultrathin NiO nanosheets. As for electrochemical pseudocapacitor application, the obtained material exhibits not only high specific capacitances of 435 F·g^-1 at 20 mV·s^-1 and 367 F·g^-1 at 10 A·g^-1, but also holds a good electrochemical stability over 1000 cycles at a current rate of 20 mV·s^-1. These results suggest that the hierarchical structured porous NiO is a promising supercapacitor electrode material.

Electrochemical Reduction Of Co2 On Sn/Cu Electrodes, Chen-Chen Zhao, Jian-Wei Guo, Li Wang, Xiang-Ming He, Cheng Wang, Zhi-Xiang Liu

Journal of Electrochemistry

The Sn/Cu electrodes were prepared by electroplating method and their morphologies under different galvanization current densities were determined by SEM. In alkali, the effects of Sn/Cu electrodes on the activities towards hydrogen evolution and electrochemical reduction of CO₂ were investigated in alkaline solutions using a three-electrode system. These results indicated that the Sn/Cu electrodes prepared at 10 mA/cm² and 15 mA/cm² showed good activities, while that prepared at 15 mA/cm² was even better in activities. The synergetic structure of the Sn/Cu electrode to be beneficial to electrochemical reduction of CO₂ has been pointed out.

Electrochemical Properties Of The Keggin-Type Lacunary Heteropolysilicate Anion And Its Eectrocatalysis For H2O2 Reduction, Xi-Long Liu, Chun-Yan Wu, Fang Zhou, Hong-Sheng Liu, Ying-Jie Hua, Chong-Tai Wang, Xiao-Yang Liu

Journal of Electrochemistry

Electrochemical properties of the Keggin-type lacunary heteropolysilicate anion SiW₁₁O₃₉^8- (SiW₁₁) and its indirect electrocatalysis for H₂O₂ reduction in the supporting electrolyte containing 0.1 mol·L^-1 NaHSO₄ and Na₂SO₄ solutions were investigated using cyclic voltammetry, square wave voltammetry and alternating current impedance spectroscopy. Experimental results indicated that SiW₁₁ showed two pairs of reversible redox waves on the glassy carbon (GC) electrode in an acidic solution. The electron transfer number corresponding to the two pairs of waves was one, and the proton transfer number involved was two during …

Electrochemical Study Of Protein Modification, Jing Zhao, Xiao-Li Zhu, Gen-Xi Li

Journal of Electrochemistry

Protein post-translational modification is a key physiological procedure, which has received more and more research interests from the scientists not only in protein science but also in some other fields. The usually employed techniques for the study of protein modification include mass spectrum, affinity chromatography, etc. Considering the complexity of protein modification and the urgent demand of such kind of study, it is highly required to develop new techniques to perform more studies. Electrochemical methods, which have been widely used in chemical study and analysis, are playing an increasingly important role in many fields of biological studies. The modification of …

NaXMYFe(Cn)6(M=Fe, Co, Ni): A New Class Of Cathode Materials For Sodium Ion Batteries, Jiang-Feng Qian, Min Zhou, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

Three types of Prussian blue compounds, Na_xM_yFe(CN)₆ (M = Fe, Co, Ni), were prepared simply by solution precipitation method and tested as cathode materials for sodium-ion batteries. X-ray diffraction and SEM measurements demonstrated that the prepared materials, namely, NaFeFe(CN)₆, Na₂CoFe(CN)₆, and Na₂NiFe(CN)₆, exhibited a perfect cubic structure with a particle size of several tens nanometers. Cyclic voltammetric and galvanostatic cycling tests revealed very different electrochemical behaviors of these three materials. The specific capacities of NaFeFe(CN)₆ and Na₂CoFe(CN)₆ could reach 113 mAh·g …

Preparation And Electrochemical Performance Of Mo-Doped Li3V2(Po4)3/C Cathode Materials, Zhi-Yuan Tang, Wei Yuan, Ji Yan, Wen-Feng Mao, Li Ma

Journal of Electrochemistry

The molybdenum-doped Li₃V_2-xMo_x(PO₄)_3/C (x = 0.01, 0.02 and 0.03) cathode materials were prepared with a sol-gel method by using Li₂CO₃, NH₄H₂PO₄, V₂O₅ and MoO₃ as raw materials, and citric acid as both chelating reagent and carbon source. The X-ray diffraction (XRD) analyses showed that the crystal structure of as-prepared samples is monoclinic with space group P2₁/n. Scanning electron microscopy (SEM) observations indicated the uniform morphology for Li₃Mo_0.02V_1.98(PO₄) …

Synthesis And Electrochemical Properties Of Lifeso4F/Graphene Composite As Cathode Material For Lithium-Ion Batteries, Wei Guo, Ya-Xia Yin, Li-Jun Wan, Yu-Guo Guo

Journal of Electrochemistry

The LiFeSO₄F was successfully synthesized from the reactions of FeSO₄∙xH₂O (x=1, 4, 7) with LiF in tetraethylene glycol media through a facile low temperature method. The structures and microscopic features of the products were characterized by XRD, SEM and TEM. TGA result shows the good thermal stability of the as-prepared LiFeSO₄F. No diffraction peaks of the FeSO₄ are observed in the as-prepared products with the starting material of either FeSO₄∙4H₂O or FeSO₄∙7H₂O, which should be ascribed to delaying the release of H_{2 …}

Corrosion Inhibition Of 316l Steel Using Sodium Diethyl Dithiocarbamate Solution In Simulated Crude Oil, Xiao-Guang Ren, Jie Yang

Journal of Electrochemistry

The corrosion inhibition behaviors of 316L steel using the sodium diethyl dithiocarbamate (SDDTC) compound in the crude simulation solution were studied in the absence and presence of zinc sulfate or sodium chromate with different compositions. Experiment resultss showed that in the environments of highly acidic and high concentrations of chloride ions the SDDTC compound could well inhibit the corrosion of 316L steel. The good synergic effects on the corrosion inhibition of 316L steel by additions of either zinc sulfate or sodium chromate into SDDTC compound were indicated in this study, which is of great significance and importance in practical applications.

Synthesis And Theoretical Studies Of Pyridyl Fullerene Derivatives For Supramolecular Applications In Photovoltaic Systems, Robert Vina-Marrufo ^, Danisha M. Rivera-Nazario, Agustin Molina-Ontoria, Luis Echegoyen *

COURI Symposium Abstracts, Spring 2012

No abstract provided.

Towards One Key To One Lock: Catalyst Modified Indium Oxide Nanoparticle Thin Film Sensor Array For Selective Gas Detection, Kun Yao, Daniela Caruntu, Sarah Wozny, Rong Huang, Yumi H. Ikuhara, Baobao Cao, Charles J. O'Connor, Weilie Zhou

Advanced Materials Research Institute (AMRI)

Homogeneous In2O3 nanoparticles (NPs) were self-assembled into thin film sensor arrays on a single chip, with further surface modification by noble metal catalysts. The NP film sensor arrays show clear current responses when exposed to different target gases, and both sensitivity and selectivity were greatly improved. Particularly, the sensors modified with Au, Pd, and Pt nanocatalysts demonstrated higher sensitivity to H2S, H-2 and CO, respectively, making the gas discrimination direct and simple, like "one key to one lock". The particle size dependence of the noble metal modifiers to the sensitivity was further investigated by tuning the sputtering parameters. Three different …

Electrocatalytic Study Of Pseudomonas Aeruginosa Bte-1 Strain, Ping Zhou, En-Ren Zhang, Li Zhou, Guo-Wang Diao, Jun-Le Niu

Journal of Electrochemistry

The aim of the present study is to investigate the electrocatalytic activity of electricity-producing Pseudomonas aeruginosa BTE-1 strain under anaerobic conditions. Pseudomonas aeruginosa BTE-1 was inoculated into anaerobic three-electrode electrochemical cells, and the electrocatalytic activity was measured at poised potentials. HPLC and cyclic voltammetry were used to detect potential electron mediators in solutions. Experimental results showed that no detectable pyocyanine was excreted by P. aeruginosa BTE-1 strain in the anaerobic electrochemcial cells, and P. aeruginosa BTE-1 exhibited direct electrocatalytic activity through the formation of biofilm on the electrode surface which was induced by the electron transfer from the cells of …

Preparation And Electrochemical Performance Of Lifepo4/C By Spray Drying Method Assisted With Organic Template, Quan-Bing Liu, Yang-Mei Jiang, Hui-Yu Song, Shi-Jun Liao

Journal of Electrochemistry

In this work, the LiFePO₄/C composites were prepared by the spray drying and carbothermal method, and were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge measurements. The effects of the organic assisted templates on the morphologies and electrochemical properties of the LiFePO₄/C composites were investigated. The results showed that the morphology and microstructure of the composites could be tuned by incorporating with the different templates. The morphology of the composite appeared to be solid microspheres if no organic template was added, while porous microspheres, nest-like …

Synthesis And Electrochemical Performance Of Xlifepo4·Yli3V2(Po4)3 Composites, Ping-Ping Ma, Zhi-Jian Liu, Jian-Hua Xia, Yu Chen, Pu Hu, Zhi-Chao Lu, Ding-Guo Xia

Journal of Electrochemistry

A series of xLiFePO₄·yLi₃V₂(PO₄)₃ composites were systematically synthesized through solid state reactions by variations in the proportions of LiFePO₄ and Li₃V₂(PO₄)₃. The properties of the prepared compounds were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and electrochemical measurements. The capacity of 162.7 mAh/g at 0.2 C rate was obtained with the relatively good cycle stability and good conductivity for 0.95LiFePO₄·0.05Li₃V₂(PO₄)₃ due to more uniformed distributed and smaller particle sizes.

Preparation And Characterization Of Mno/Tin Anode For Lithium Ion Batteries, Gao-Jie Xu, Hai-Yan Yang, Peng-Xian Han, Li-Xue Zhang, Ke-Jun Zhang, Chuan-Jian Zhang, Yu-Hua Fan, Cai-Feng Bi, Guang-Lei Cui

Journal of Electrochemistry

Manganese titanate (MnTiO₃) powder was prepared via a sol-gel method using manganese acetate and tetrabutyl titanate as raw materials, and citric acid as a chelating agent. Through high temperature nitridation of MnTiO₃ powder in ammonia, the MnO/TiN composite was obtained. The phase structure, composition and morphology of the composites were characterized by XRD, SEM and EDS. The electrochemical properties of the composite electrodes were studied by performing cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy tests. The MnO/TiN electrode delivered specific capacities of 394 mAh·g^-1 and 146 mAh·g^-1 at the current density of …

Preparation And Hydrogen Evolution Properties Of Ni/Ag2O/Ruo2-Pt Cathodes, Shu Huang, Xue-Ming Li, Wu-Lin Li, Wen Wang

Journal of Electrochemistry

The Ni/Ag₂O/RuO₂-Pt composite cathode was prepared by sol-gel method using RuCl₃ and H₂PtCl₆ as raw materials. The effects of heat treatment conditions and AgNO₃ concentrations on hydrogen evolution properties were investigated. The morphology and composition of Ni/Ag₂O/RuO₂-Pt composite cathode have been characterized by XRD, XPS and SEM-EDS. It is demonstrated that the surface structure of Ni/Ag₂O/RuO₂-Pt composite cathode is more compact, with fewer cracks and larger surface roughness than pure nickel. At the conditions of 0.3 A·cm^-2, 90 ^oC, and …

Progress And Perspective Of Fuel Cell Technology, Ming Hou, Bao-Lian Yi

Journal of Electrochemistry

Fuel cell, a clean and high-efficiency electrochemical power source, has being paid much attention worldwide recent years. In this paper, the progress and perspective of fuel cell technology are elucidated in detail. Fuel cells have been applied in some special fields such as spacecraft, shuttle and submarines. However, in the areas of transportation, stationary station and portable power source, fuel cells are still under demonstration due to the durability and cost problems. The reliability and surrounding survivability of fuel cells should be enhanced in the special application. Meanwhile, the durability and cost of fuel cells are the main issues to …

The Electrocatalytic Study Of Licoo2 In Air Electrode For Lithium-Air, Jun Gao, Wei Wu, Yan-Yan Tian, Yong Yang

Journal of Electrochemistry

The LiCoO₂ has been investigated as a new electrocatalyst for air electrodes using homemade lithium-air battery. The electrochemical performance and structural changes of the LiCoO₂ based composite air electrodes have been studied. The results of CV, XRD and charge-discharge tests show that the composite air electrodes composed of LiCoO₂ can greatly improve the discharge performance of lithium-air batteries. In particular when the composite air electrodes are charged to 4.1 V before further discharging, the obvious catalytic effects of LiCoO₂ are attributed to higher valence state of the Co element in LiCoO₂, esp. at charged …

Dissolved Oxygen Seawater Battery With Electrochemical Capacitance, Hai-Bo Xu, Yong-Hong Lu, Wei Zhang, Yan-Ting Yu, Chuan-Wei Yan, Ya-Ping Sun, Lian Zhong, Jian-Guo Liu, Yi Zheng, Bing Han, Yong-Liang Wang

Journal of Electrochemistry

A new concept of seawater battery with electrochemical capacitance (SWB-EC) has been proposed using carbon fibre brush (CFB) as the cathode material, and three testing prototypes have been made accordingly. The discharge performances of the CFB before- and after-oxidation and Mg alloy sacrifice anode were studied by cyclic voltammetry and constant current discharge tests under steady state conditions. Results show that the oxidized CFB exhibits the pseudo-capacitive characteristic and its activity of oxygen reduction reaction (ORR) in stirred seawater highly increases, comparing with the non-oxidized CFB. The open circuit potential of Mg alloy sacrifice anode is -1.74 V, having the …

Electrochemical Characterization Of (Phmgcl)2-Alcl3/Mixed Ether Electrolytes, Fei-Fei Wang, Yong-Sheng Guo, Jun Yang, Li-Yan-Na Nu, Jiu-Lin Wang

Journal of Electrochemistry

The (PhMgCl)₂-AlCl₃ salts were prepared and the electrochemical properties of (PhMgCl)₂-AlCl₃ electrolytes containing dimethoxyethane(DME)+THF, Diglyme(DG)+THF and Tetraglyme(TG)+THF solvents with different proportions on various metal electrodes were studied. Compared with (PhMgCl)₂-AlCl₃/THF, the (PhMgCl)₂-AlCl₃/DG+THF(3:2) solvents showed high ionic conductivity of 1.605×10^-3 S·cm^-1, good reversible Mg deposition behavior and anodic anti-oxidation performance with an electrochemical window wider than 2.8 V. In addition, the DG+THF mixed solvent could greatly lower the saturated vapor pressure by reducing from 23.46 kPa to 9.41 kPa, which suppresses volatilization of the …

Simultaneous Determinations Of Ascorbic Acid, Dopamine And Uric Acid At Ca/Gc Electrode, Ying Zhang, Wang Ren, Min-Jiao Li

Journal of Electrochemistry

The citric acid modified glassy carbon electrode (CA/GC) was constructed by potentiostatic technique and used for simultaneous determinations of ascorbic acid (AA), dopamine (DA) and uric acid (UA) by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CA/GC electrode exhibits excellent electrocatalytic activity towards AA, DA and UA. The oxidation peaks are well separated with the potential differences between AA and DA, DA and UA, and AA and UA being 170, 130 and 300 mV, respectively, which is large enough to determine AA, DA and UA simultaneously. The catalytic peak currents obtained were linearly dependent on the concentrations of …

Cycle Lifetime Investigation Of Nickel Electrode Prepared By Electrochemical Impregnation For Applications In Aerospace Nickel Hydrogen Cells, Hai-Chang Zhang, Li-Xin Tan, Cheng Guo, Wen-Cheng Ming, Xue-Ying Ren

Journal of Electrochemistry

In this paper, the effects of overcharge, charge-discharge C rate and pore size on cycle lifetime of 4.5’ electrochemical impregnated nickel electrode were investigated. In the case of the electrode was overcharged to 170% of nominal capacity, the initial capacity of the electrode could be maintained 2.7 Ah up to 150 cycles without deterioration and a discharge capacity of 1.7 Ah (remaining 63% of 2.7 Ah) could be delivered after 300 cycles. Without overcharge, more than 300 charge-discharge cycles could be realized without loss of capacity and a discharge capacity of electrode could be maintained about 76% of initial capacity …

Ag Nanoparticles Self-Assembled Films On Iron Surface And Their Inhibition Properties, Zhe Zhang, Ming-Zi Jia, Le Ruan

Journal of Electrochemistry

The Ag nanoparticles were prepared in aqueous solutions through a chemical reduction method and transferred from water phase to toluene phase with the protection of 1-dodecanethiol (DDT). The polished iron electrode was immersed in the DDT-protected metal nanoparticles toluene solutions to form DDT/Ag nanoparticles self-assembled mixed films. Electrochemical methods such as electrochemical impedance spectroscopy and polarization curve measurement were used to study the inhibition properties of the self-assembled films in the 0.5 mol·L^-1 H₂SO₄ solution. The appearance of elements such as S and Ag from the XPS data identified the presences of DDT and Ag nanoparticles.

Horizontally-Aligned Carbon Nanotubes Arrays And Their Interactions With Liquid Crystal Molecules: Physical Characteristics And Display Applications, Frederick Roussel, Jean-Francois Brun, Alexandre Allart, Limin Huang, Stephen O'Brien

Publications and Research

We report on the physical characteristics of horizonthally-grown Single-Walled Carbon Nanotubes (h-al-SWNT) arrays and their potential use as transparent and conducting alignment layer for liquid crystals display devices. Microscopy (SEM and AFM), spectroscopic (Raman) and electrical investigations demonstrate the strong anisotropy of h-al-SWNT arrays. Optical measurements show that h-al-SWNTs are efficient alignment layers for Liquid Crystal (LC) molecules allowing the fabrication of optical wave plates. Interactions between h-al-SWNT arrays and LC molecules are also investigated evidencing the weak azimuthal anchoring energy at the interface, which, in turn, leads to LC devices with a high pretilt angle. The electro-optical reponses of …

Ƴ-Selective Directed Catalytic Asymmetric Hydroboration Of 1,1-Disubstituted Alkenes, Sean M Smith, Gia L. Hoang, Rhitankar Pal, Mohammad O. Bani Khaled, Liberty S. W. Pelter, Xiao Cheng Zeng, James M. Takacs

Xiao Cheng Zeng Publications

Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford ƴ

-dioxaborato amides and esters in high enantiomeric purity (90–95% ee).

Synthesis And Flame Retardant Testing Of New Boronated And Phosphonated Aromatic Compounds, Vladimir Benin, Sravanthi Durganala, Alexander Morgan

Chemistry Faculty Publications

The present report describes the preparation and use of some dimethyl terephthalate derivatives in transition metal-catalyzed coupling reactions to produce new reactive flame retardants. Dimethyl iodoterephthalate and dimethyl 2,5-diiodoterephthalate were successfully employed in the preparation of phosphonic and boronic esters and acids. The latter were tested for heat release with a microcombustion calorimeter (ASTM D7309) to determine the potential for heat release reduction of these flame retardant molecules. The results showed that the addition of boronic or phosphonic acids greatly lowered the heat release, due to a condensed phase (char formation) mechanism. Adding ester groups to the boronic acids or …

Development Of Tailor-Designed Gold-Platinum Nanoparticles Binary Catalysts For Efficient Formic Acid Electrooxidation, Islam M. Al-Akraa Dr, Ahmad M. Mohammad Prof, Mohamed S. El-Deab Prof, Bahgat E. El-Anadouli Prof

Chemical Engineering

The modification of a glassy carbon (GC) electrode with platinum (PtNPs) and gold (AuNPs) nanoparticles is targeted to fabricate efficient anodes for the electrooxidation of formic acid (FA). A proper adjustment of the deposition sequence of PtNPs and AuNPs could eventually enhance the electrocatalytic activity of the electrode in such a way that suppresses the CO poisoning effect during FA oxidation. The highest catalytic activity is obtained at the Au/Pt/GC electrode (with PtNPs firstly deposited on the GC electrode followed by AuNPs). This superb enhancement is quantified by comparing the relative ratio of the direct vs. the indirect oxidation peaks …

Self-Assembling Subnanometer Pores With Unusual Mass-Transport Properties, Xibin Zhou, Guande Liu, Kazuhiro Yamato, Yi Shen, Ruixian Cheng, Xiaoxi Wei, Wanli Bai, Yi Gao, Hui Li, Yi Liu, Futao Liu, Daniel M. Czajkowsky, Jingfang Wang, Michael J. Dabney, Zhonghou Cai, Jun Hu, Frank V. Bright, Lan He, Xiao Cheng Zeng, Zhifeng Shao, Bing Gong

Xiao Cheng Zeng Publications

A long-standing aim in molecular self-assembly is the development of synthetic nanopores capable of mimicking the mass-transport characteristics of biological channels and pores. Here we report a strategy for enforcing the nanotubular assembly of rigid macrocycles in both the solid state and solution based on the interplay of multiple hydrogen-bonding and aromatic π − π stacking interactions. The resultant nanotubes have modifiable surfaces and inner pores of a uniform diameter defined by the constituent macrocycles. The self-assembling hydrophobic nanopores can mediate not only highly selective transmembrane ion transport, unprecedented for a synthetic nanopore, but also highly efficient transmembrane water permeability. …