Open Access. Powered by Scholars. Published by Universities.®

Chemistry Commons™

Open Access. Powered by Scholars. Published by Universities.®

Articles 571 - 600 of 2389

Full-Text Articles in Chemistry

Preparation And Properties Of Nanocrystalline Nickel By Pulse Electrodeposition On Glassy Carbon, Ya-Li Zhang, Ming-Xian Zhang, Teng-Da Guo, Yan-Jie Zhao, Sheng-Xue Yu Feb 2018

Preparation And Properties Of Nanocrystalline Nickel By Pulse Electrodeposition On Glassy Carbon, Ya-Li Zhang, Ming-Xian Zhang, Teng-Da Guo, Yan-Jie Zhao, Sheng-Xue Yu

Journal of Electrochemistry

Nanocrystalline nickel exhibits electrocatalytic activity for methanol. In this work, nanocrystalline nickel coating has been obtained by using the double pulse method on glassy carbon materials surface. The influence of pulse conditions on the grain size of nanocrystalline nicke was studied. The concentrations and compositions of the plating bath were  300 g·L-1 NiSO4·6H2O,45 g·L-1 NiCl2·6H2O,40 g·L-1 H3BO3,5 g·L-1 C7H5NO3S,and 0.05 g·L-1 C12H25NaO4S. The optimal pulse process parameters including the average pulse …


Synthesis And Electrochemical Properties Of Nickel-Rich Cathode Material Lini0.6Co0.2Mn0.2O2 With High Initial Coulombic Efficiency, Xiao-Yun Guan, Chao-Yu Hong, Jian-Ping Zhu, Wei-Li Wang, Yi-Xiao Li, Yong Yang Feb 2018

Synthesis And Electrochemical Properties Of Nickel-Rich Cathode Material Lini0.6Co0.2Mn0.2O2 With High Initial Coulombic Efficiency, Xiao-Yun Guan, Chao-Yu Hong, Jian-Ping Zhu, Wei-Li Wang, Yi-Xiao Li, Yong Yang

Journal of Electrochemistry

Nickel-rich cathode materials LiNi0.6Co0.2Mn0.2O2(NCM622)were synthesized by a co-precipitation-solid state sintering method at different temperatures. The structure, morphology and electrochemical performance of the as-prepared materials were investigated by X-ray powder diffraction (XRD) /Rietveld refinement, scanning electron microscope (SEM) and electrochemical experiments. It is found that NCM622 calcined at 800 ℃ showed the lowest degree of cation disorder (~1.97%) with a high initial Coulombic effiency of 92.2% and the capacity retention of 81.4% after 100 cycles.


Electrodeposition Of Cigs Thin Film With Special Structure Using Laser Etching Template, Jin-Zhi Yu, Ye Lian, Jin-Qiu Zhang, Pei-Xia Yang, Mao-Zhong An Feb 2018

Electrodeposition Of Cigs Thin Film With Special Structure Using Laser Etching Template, Jin-Zhi Yu, Ye Lian, Jin-Qiu Zhang, Pei-Xia Yang, Mao-Zhong An

Journal of Electrochemistry

Copper indium gallium selenide (Cu1.00InxGa1-xSe2.00, CIGS) thin film solar cells have a wide application in semiconductor thin film batteries. The CIGS absorbing layer is the key of the thin film solar cell material. Therefore, it is of theoretical and practical significance to carry out researches in CIGS thin films. In this work, the CIGS thin films with special structures were prepared by using laser etching template. The copper thin film was firstly electrodeposited in aqueous solution with Laser etching template. The influences of temperature, current and concentration of copper sulfate on morphology …


An Electrochemical Investigation In The Anticorrosive Properties Of Silver Nanoparticles For The Acidic Corrosion Of Aluminium, H. A. Fetouh, B. A. Abd-El-Nabey, Y. M. Goher, M. S. Karam Feb 2018

An Electrochemical Investigation In The Anticorrosive Properties Of Silver Nanoparticles For The Acidic Corrosion Of Aluminium, H. A. Fetouh, B. A. Abd-El-Nabey, Y. M. Goher, M. S. Karam

Journal of Electrochemistry

The mass loss, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were used for the determinations of the corrosion rates for aluminium in 1.0 mol·L-1 hydrochloric acid (HCl) solutions both in the absence and presence of silver nanoparticles (SNPs) at 30 ℃. The protection efficiency was evaluated to be 96.4% for 0.014 g·L-1 of the SNPs. It has been found that the capacity of the electrical double layer at the aluminium/solution interface was decreased with increasing the concentration of the SNPs, indicating that the SNPs were adsorbed at the aluminium surface. The Langmuir adsorption isotherm and the kinetic-thermodynamic …


Preface For Special Issue On Electroplating And Surface Finishing, Mao-Zhong An Feb 2018

Preface For Special Issue On Electroplating And Surface Finishing, Mao-Zhong An

Journal of Electrochemistry

/


Superhydrophobic Surface On Aluminum Alloy By Hydrothermal Method And Its Electrochemical Performance, Xiao-Hang Chen, Mo-Jing Chen, Yu-Lin Min, Qun-Jie Xu Feb 2018

Superhydrophobic Surface On Aluminum Alloy By Hydrothermal Method And Its Electrochemical Performance, Xiao-Hang Chen, Mo-Jing Chen, Yu-Lin Min, Qun-Jie Xu

Journal of Electrochemistry

Superhydrophobic film formed on a metal surface is an effective way for corrosion protection. In this paper, the superhydrophobic film was prepared on the surfaces of aluminum alloy by hydrothermally treating with a solution containing CeCl3·7H2O and CO(NH2)2 , and a self-assemble process. The electrochemical measurements and surface morphology results confirmed that the best superhydrophobicity and electrochemical performance could be achieved with the contact angle of 155.5o after six hours of hydrothermal reaction. Furthermore, the inhibition efficiency of 99.6% was obtained in 3.5 wt% NaCl aqueous solution, indicating the excellent corrosion resistance …


Intrinsic Kinetic Properties Of Ternary Material For Lithium Ion Batteries Assessed By Single Particle Microelectrode, Yi-Min Wei Feb 2018

Intrinsic Kinetic Properties Of Ternary Material For Lithium Ion Batteries Assessed By Single Particle Microelectrode, Yi-Min Wei

Journal of Electrochemistry

Electrochemical performances such as capacity, rate, cycle and thermal stability of the nickel (Ni), cobalt (Co) and manganese (Mn) ternary cathode material, LiNixCoyMnzO2 (x + y + z = 1), are significantly influenced by the proportion of Ni, Co, and Mn elements. To obtain higher specific capacity, LiNi0.6Co0.2Mn 0.2O2 (NCM622) and LiNi0.8Co0.1Mn0.1O2 (NCM811) with high amounts of Ni element were employed for the lithium ion batteries. By now, many studies have been focusing on the thermal and cycling stabilities of …


Preparation And Electrocatalytic Activity Of Nitrogen-Doping Tungsten Carbide Catalyst, Pian-Pian Yang, Li-Zhen Huang, Ying-Ying Li, Mei-Qin Shi, Chun-An Ma Feb 2018

Preparation And Electrocatalytic Activity Of Nitrogen-Doping Tungsten Carbide Catalyst, Pian-Pian Yang, Li-Zhen Huang, Ying-Ying Li, Mei-Qin Shi, Chun-An Ma

Journal of Electrochemistry

Tungsten carbide (WC) is a promising electrocatalyst, however, its electrocatalytic activity is far inferior to Pt and Pt-group metal. In this work, nitrogen-doping tungsten carbide (WN|WC) catalysts with a nanoplate morphology were prepared via the tungsten nitride (WN) as the precursor and sodium tungstate as the tungsten source. The SEM and TEM results indicated that carbon atoms entered into the WN lattice to form the hexagonal close packed WC phase. In this way, an atomic scale heterostructure involving the closely linked interfaces between WN and WC was created . The XRD data confirmed that the cubic crystal structure of WN …


Deposition Mechanism And Coating Characterization For The Trivalent Chromium Electrodeposition In Sulphate Electrolyte, Hui Yan, Shuai-Shuai Huang, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min Zhou Feb 2018

Deposition Mechanism And Coating Characterization For The Trivalent Chromium Electrodeposition In Sulphate Electrolyte, Hui Yan, Shuai-Shuai Huang, Fang-Zu Yang, Zhong-Qun Tian, Shao-Min Zhou

Journal of Electrochemistry

Linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were used to study the electrodeposition mechanism of trivalent chromium on a copper electrode in the novel sulphate electrolyte for thick trivalent chromium plating. The thickness, morphology, composition, microhardness, and structure, as well as the corrosion resistance in 3.5wt% NaCl solution of the trivalent chromium coatings were investigated by X-ray fluorescence gage, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), microhardness tester, X-ray diffraction (XRD) and Tafel curve measurements. The results showed that the electrodeposition of trivalent chromium involved two consecutive one electron reduction steps. The first step, Cr3+ + e …


Surface Ehancement Of Nickel Ions On Cyanide Free Immersion Gold Deposited From A Chloroauric Acid-Choline Chloride Solution On Medium-Phosphorus Nickel, Tian-Yu Xu, Shi-Ying Wang, Wen-Chang Wang, Zhi-Dong Chen Feb 2018

Surface Ehancement Of Nickel Ions On Cyanide Free Immersion Gold Deposited From A Chloroauric Acid-Choline Chloride Solution On Medium-Phosphorus Nickel, Tian-Yu Xu, Shi-Ying Wang, Wen-Chang Wang, Zhi-Dong Chen

Journal of Electrochemistry

The nickel ions (Ni2+) were introduced into choline chloride (ChCl) cyanide free immersion gold solution to improve the surface quality of electrodeposition on medium-phosphorus nickel substrate. The addition of Ni2+ had no significant impact on the plating speed. However, the hyperactive corrosion of nickel substrate could be effectively alleviated by the addition of 500 mg·L-1 NiCl2·6H2O, and the surface morphology of gold coating could be greatly improved. The choline chloride bath has great potential for industrial production due to its high Ni2+ carrying capacity (2000 mg·L-1) and superior applicability …


Effects Of Carboxylic Acids On Structure And Performance Of 10% Vanadium Modified Li2Fesio4/C Composites, Xue-Xia Wei, Jia-Qi Huang, Shi-Yang Liu, Xuan Cheng, Ying Zhang Feb 2018

Effects Of Carboxylic Acids On Structure And Performance Of 10% Vanadium Modified Li2Fesio4/C Composites, Xue-Xia Wei, Jia-Qi Huang, Shi-Yang Liu, Xuan Cheng, Ying Zhang

Journal of Electrochemistry

The carbon coated 10% vanadium modified lithium iron silicate (Li2Fe0.9V0.1SiO4/C) composites were prepared by sol-gel method to form precursor and followed by solid state reaction. Effects of different carboxylic acids, namely, citric acid, acetic acid and oxalic acid, on the crystal structures, surface morphologies, interfacial characteristics and electrochemical properties of the composites were systematically investigated. It was found that a mixed P21 and Pmn21 phase was formed with the major impure phase of iron (Fe) and minor impurity of lithium silicate (Li2SiO3). The initial discharge capacities …


Applications Of Electrospinning In Lithium-Air Batteries, Yue Fu, Jin Wang, Hai-Yang Yu, Jing-Hua Tian, Rui-Zhi Yang Feb 2018

Applications Of Electrospinning In Lithium-Air Batteries, Yue Fu, Jin Wang, Hai-Yang Yu, Jing-Hua Tian, Rui-Zhi Yang

Journal of Electrochemistry

Lithium-air batteries have received increasing attention as the “ultimate batteries” due to their extremely high theoretical capacity and environment friendly. However, there are still many obstacles hindering the wide applications of the lithium-air batteries owing to the limitations of large charge-discharge over-potentials, poor Columbic efficiency and cycling performance. Exploring of high-efficiency, low-cost and eco-friendly catalysts is one of the vital issues for lithium-air batteries. Meanwhile, electrospinning techniques have been under substantial developments due to its simple fabrication process, high efficiency and production. This paper reviews the recent progresses in fabrications of various novel catalysts for lithium-air batteries with electrospinning techniques, …


Preparation Of Nis2 Nanosheet And Its Application In Asymmetric Supercapacitor, Yuan-You Wang, Ya-Nan Liu, Dang-Qin Jin Dec 2017

Preparation Of Nis2 Nanosheet And Its Application In Asymmetric Supercapacitor, Yuan-You Wang, Ya-Nan Liu, Dang-Qin Jin

Journal of Electrochemistry

In this work, the NiS2 nanosheets have been synthesized using Ni(OH)2  as a precursor through a sacrificial template method. The microstructure and chemical composition of as-prepared NiS2 were characterized by XRD, EDS, BET, SEM and TEM techniques. The results showed that both Ni(OH)2  and NiS2  were composed of nanoplates. The electrochemical tests revealed that NiS2 exhibited the high specific capacitance of 1067.3 F•g-1 at a current density of 1 A•g-1 and excellent rate performance. Furthermore, in order to evaluate the practical application of NiS2, an asymmetric supercapacitor, NiS2 as …


Electroactivities Of Pd/Fe3O4-C Catalysts For Electro-Oxidation Of Methanol, Ethanol And Propanol, Tao Zou, Qing-Feng Yi, Yuan-Yuan Zhang, Xiao-Ping Liu, Guo-Rong Xu, Hui-Dong Nie, Xiu-Lin Zhou Dec 2017

Electroactivities Of Pd/Fe3O4-C Catalysts For Electro-Oxidation Of Methanol, Ethanol And Propanol, Tao Zou, Qing-Feng Yi, Yuan-Yuan Zhang, Xiao-Ping Liu, Guo-Rong Xu, Hui-Dong Nie, Xiu-Lin Zhou

Journal of Electrochemistry

Development of palladium (Pd) catalysts with high electroactivity for alcohol oxidation is significant for alcohol fuel cells. In this work, Pd nanoparticles were formed by sodium borohydride (NaBH4) reduction method and subsequently deposited on the surface of carbon supported ferriferrous oxide (Fe3O4/C) composites to obtain the Pd/Fe3O4-C catalysts with different Fe3O4 loadings. Their transmission electron microscopic (TEM) images show that the Pd nanoparticles were uniformly dispersed on the Fe3O4/C. Electroactivities of the prepared Pd/Fe3O4-C catalysts toward oxidations of C1-C3 …


Kinetics And Mechanism Toward Electrochemical Reductions Of Sodium Bromide And Methanol Over Iron Electrodes, Qun Liao, Shu-Feng Zhang, Wen-Hua Leng Dec 2017

Kinetics And Mechanism Toward Electrochemical Reductions Of Sodium Bromide And Methanol Over Iron Electrodes, Qun Liao, Shu-Feng Zhang, Wen-Hua Leng

Journal of Electrochemistry

It is of technological value and scientific interest to the electro-synthesis of ferrocene, conversion of carbon dioxide (CO2) and organic electro-synthesis in non-aqueous solutions by investigating the kinetics and mechanism toward electrochemical reductions of sodium bromide (NaBr) and methanol over iron electrodes. However, few reports in the related researches are available. In this article, the kinetics and mechanism toward electrochemical reductions of NaBr and methanol over iron electrodes were examined in detail by carrying out the polarization curve and electrochemical impedance spectroscopic measurements. The results showed that methanol was the reactant, while Na+ ions were functioned only …


Effect Of Peg-Coating On Properties Of Lithium-Sulfur Battery Cathode Material Containing Carbon Fiber Conductive Agent, Jie-Cheng Tan, Yan-Hong Tian, Xue-Jun Zhang, Kai-Le Fan Dec 2017

Effect Of Peg-Coating On Properties Of Lithium-Sulfur Battery Cathode Material Containing Carbon Fiber Conductive Agent, Jie-Cheng Tan, Yan-Hong Tian, Xue-Jun Zhang, Kai-Le Fan

Journal of Electrochemistry

The composite materials contained high modulus carbon fiber (HMCF) were successfully prepared by employing a ball-milling process based on the coating treatment of polyethylene glycol (PEG), and their structures and morphologies were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques.The influences of PEG content on sulfur cathode capacity, cycle stability and rate performance were systematically studied. It was found that by the pre-coating of PEG, the cathode exhibited the high initial discharge specific capacity of 1312.5 mAh⋅g-1 at a current rate of 0.2C, and the reversible discharge capacity of 650 mAh⋅g …


Capacity Fading Analyses Of Lini0.5Co0.2Mn0.3O2And Lini0.5Co0.2Mn0.3O2/Lifepo4 Cathode Materials For Lithium-Ion Battery, Yi Hu, Xiang-Zhu He, Zhong-De Deng, Ling-Yong Kong, Wei-Li Shang Dec 2017

Capacity Fading Analyses Of Lini0.5Co0.2Mn0.3O2And Lini0.5Co0.2Mn0.3O2/Lifepo4 Cathode Materials For Lithium-Ion Battery, Yi Hu, Xiang-Zhu He, Zhong-De Deng, Ling-Yong Kong, Wei-Li Shang

Journal of Electrochemistry

The LiNi 0.5Co 0.2Mn 0.3O2/LiFePO4 (NMC532/LFP) composite cathode material for lithium-ion battery was prepared by wet ball-milling. The capacity fading behaviors of LiNi 0.5Co 0.2Mn 0.3O2 (NMC532) and LiNi 0.5Co 0.2Mn 0.3O2/LiFePO4 (NMC532/LFP) were analyzed by X-ray diffraction (XRD), scanning electron microscope (SEM), charge/discharge and electrochemical impedance spectroscopy (EIS) tests. The results indicated that the capacity retention values of NMC532/LFP were 97.80% and 86.48%, respectively, after 50 cycles and 60℃ high temperature storage. The NMC532/LFP exhibited better cycle performance and high temperature storage performance. …


Cobalt-Based Nitrogen-Doped Carbon Non-Noble Metal Catalysts For Oxygen Reduction Reaction, Meng-Xiu Jiang, Jing Zhang, Yue-Hua Li, Rong Zhang Dec 2017

Cobalt-Based Nitrogen-Doped Carbon Non-Noble Metal Catalysts For Oxygen Reduction Reaction, Meng-Xiu Jiang, Jing Zhang, Yue-Hua Li, Rong Zhang

Journal of Electrochemistry

Transition metal-nitrogen co-doped carbon catalysts have attracted significant attention because of their reasonable activity and remarkable selectivity toward oxygen reduction reaction (ORR) as cathodic reaction in fuel cells. However, the role of transition metal in the active sites of the catalysts still is uncertain. In this work, the Cox-Ny/C-T catalysts were prepared with BP2000 as a carbon source, urea (Ur) as a nitrogen source and Co(OAc)2•4H2O as a metal precursor by a simple chemical method. Meanwhile, in order to optimize the ORR activity, the catalysts were synthesized with different amounts of Co …


Electrochemical Behaviors Of Ce3+/Ce4+ Couple In A Mixed-Acid Medium Of Ch3So3H And H2So4, Zhao-Hua Li, Jiao-Long Xu, Ting Wu Dec 2017

Electrochemical Behaviors Of Ce3+/Ce4+ Couple In A Mixed-Acid Medium Of Ch3So3H And H2So4, Zhao-Hua Li, Jiao-Long Xu, Ting Wu

Journal of Electrochemistry

In order to determine the optimum molar ratio between methanesulfonic acid (MSA) and sulfuric acid, linear sweep voltammetry (LSV), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behaviors of cerium (III)/cerium (IV) (Ce3+/Ce4+couple on a Pt electrode in a mixed acid solution. Various concentrations of sulfuric acid were considered in the experiments, while the concentration of MSA was fixed at 1.0 mol·L-1. It was found that the optimum concentration of sulfuric acid was 0.8 mol·L-1 since the current response was the highest in the control groups and …


Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang Dec 2017

Core-Shell Pd@Pt Ultrathin Nanowires As Durable Oxygen Reduction Electrocatalysts, Xin Wang, Yun-Jie Xiong, Liang-Liang Zou, Qing-Hong Huang, Zhi-Qing Zou, Hui Yang

Journal of Electrochemistry

This paper describes a simple CO-assisted reduction approach for the controllable synthesis of ultrathin Pd nanowires along the one-dimensional (1D) direction. Ultrathin Pt films from one to several atomic layers were successfully decorated onto ultrathin Pd nanowires by utilizing Cu UPD deposition, and followed by in-situ redox replacement reaction of UPD Cu by Pt. The core–shell structure and composition of the Pd@Pt ultrathin nanowires have been verified using transmission electron microscopy and energy dispersive X-ray spectrometry. The core–shell Pd@Pt ultrathin nanowires exhibited comparative electrocatalytic activity and improved durability for the oxygen reduction reaction in comparison with commercial Pt black. The …


Effect Of Allyl Thiourea On Nickel Electrodeposition From Solution Containing Ammonia And Chloride, Ya-Ning He, Liang Yuan, Zhi-Ying Ding, Shi-Jun Liu Dec 2017

Effect Of Allyl Thiourea On Nickel Electrodeposition From Solution Containing Ammonia And Chloride, Ya-Ning He, Liang Yuan, Zhi-Ying Ding, Shi-Jun Liu

Journal of Electrochemistry

The effects of allylthiourea (ATU) concentration on the cathodic polarization behaviour, nucleation and surface morphology of nickel electrodeposited on the glassy carbon electrode from ammonia-ammonium chloride-water (NH3-NH4Cl-H2O) solutions were investigated by cyclic voltammogry, cathodic polarization and current transient methods. The results revealed that the addition of ATU inhibited nickel deposition, which was enhanced with an increase in ATU concentration from 5 to 50 mg•L-1. The initial deposition kinetics corresponded to a model including instantaneous nucleation and diffusion controlled growth. In the presence of ATU, the initial nucleation of nickel electrocrystallisation remained unchanged. …


Effects Of Jet Milling And Classifying Process On The Performance Of Lifepo4/C In Full Batteries, Xing-Liang Liu, Mao-Ping Yang, Wei-Wei Wang, Yong Cao Dec 2017

Effects Of Jet Milling And Classifying Process On The Performance Of Lifepo4/C In Full Batteries, Xing-Liang Liu, Mao-Ping Yang, Wei-Wei Wang, Yong Cao

Journal of Electrochemistry

The carbon coated lithium iron phosphate (LiFePO4/C) composite cathode material was prepared by using iron phosphate process. The effects of jet milling and classifying process on the electrochemical performance of LiFePO4/C cathode material in full batteries were investigted. Scanning electron microscopic analyses suggested that the globose secondary particles were crustily crushed during the jet milling and classifying process, which would further result in lower tap density and carbon content. The LiFeP4/C composite cathode materials with different physical characteristics were further tested in full batteries to evaluate the electrochemical properties. The results showed no obvious …


Engineering The Electrochemical Capacitive Properties Of Activated Carbon By Correct Selection Of Ionic-Liquid Electrolytes, Qiu-Hong Zhang, Bao-Shou Shen, Song-Lin Zuo, Xin-Yu Wei Dec 2017

Engineering The Electrochemical Capacitive Properties Of Activated Carbon By Correct Selection Of Ionic-Liquid Electrolytes, Qiu-Hong Zhang, Bao-Shou Shen, Song-Lin Zuo, Xin-Yu Wei

Journal of Electrochemistry

In order to improve the electrochemical capacitive properties and to apply coconut shell activated carbon (AC) serving as electrode materials in ionic liquid (IL)-based supercapacitor (SC), the coconut shell AC material was re-activated using a steam as an activating agent in this work, forming a secondary AC (W-AC). The results showed that the specific capacitance of the W-AC electrode was much larger than that of the raw activated carbon electrode (R-AC) in 1-ethyl-3-methylimidazolium tetrafluoroborate ([EMIM]BF4). The electrochemical techniques including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) measurement, and electrochemical impedance spectroscopy (EIS) were used to systematically study the capacitive …


Applications Of N-Methyl-N-Butyl-Pyrrolidinium Bromide And N-Methyl-N-Ethyl-Pyrrolidinium Bromide In Zn-Br Flow Batteries, Qi Zhang, Miao-Miao Zhang, Lin Meng Dec 2017

Applications Of N-Methyl-N-Butyl-Pyrrolidinium Bromide And N-Methyl-N-Ethyl-Pyrrolidinium Bromide In Zn-Br Flow Batteries, Qi Zhang, Miao-Miao Zhang, Lin Meng

Journal of Electrochemistry

It is extremely important for battery performance and safety in Zn-Br flow battery to use quaternary ammonium salts as complex agents for bromine. In this work, the effects of electrolyte compositions and concentrations on the electrode reactions and battery performances were studied in the absence and presences of N-methyl-N-ethyl-pyrrolidinium bromide (MEP) or N-methyl-N-butyl-pyrrolidinium bromide (MBP). The conductivities in the electrolytes containing different constitutions and concentrations were measured by EIS method. The charge-discharge performance for the battery and the complex ability for bromine in different electrolytes were also investigated. The results showed that the electrolyte containing MBP was better than that …


Effect Of Fe2+/Fe3+Interconvertion On Reduction Behavior Of Fe3+ In Acidic Electrolytes, Jian-Xin Qin, Feng Lin, Wen-Ping Liu, Chao Chen, Meng-De Ren Dec 2017

Effect Of Fe2+/Fe3+Interconvertion On Reduction Behavior Of Fe3+ In Acidic Electrolytes, Jian-Xin Qin, Feng Lin, Wen-Ping Liu, Chao Chen, Meng-De Ren

Journal of Electrochemistry

The influences of ferrous/ferric (Fe2+/Fe3+) interconvertion on electrochemical reduction and electrode reaction of Fe3+ were investigated by using linear sweep voltammetry, potentiostatic method and cyclic voltammetry (CV) in acidic electrolytes containing chloride ion (Cl-) and sulfate ion (SO42-). It was shown that the reduction process of Fe3+/Fe2+ would take place in two independent stages: (1) the reduction of Fe3+ to Fe2+ at E=0.35V and (2) the co-precipitation of Fe2+ by forming Fe(OH)2 (E≤-0.3 V) instead of Fe. The major effect of Fe2+ …


Effect Of Calcium On Atmospheric Corrosion Resistance Of Bridge Steel, Dong-Liang Li, Gui-Qin Fu, Miao-Yong Zhu Dec 2017

Effect Of Calcium On Atmospheric Corrosion Resistance Of Bridge Steel, Dong-Liang Li, Gui-Qin Fu, Miao-Yong Zhu

Journal of Electrochemistry

The corrosion behavior of bridge steel in simulated hot and humid industrial-marine atmosphere was investigated by mass loss analysis, XRD, SEM, electrochemical methods and a wet/dry alternate immersion corrosion test using 0.1 mol•L-1 NaCl+0.01 mol•L-1 NaHSO3 solutions. The corrosion depth (W) of experimental steels before and after calcium treatment versus time (t) curves showed a good agreement with the power function of W=Atn. The corrosion products were mainly composed of amorphous phase and a small amount of crystals including α-FeOOH, β-FeOOH, γ-FeOOH and Fe3O4. Trace calcium could promote the formation of …


Special Issue On Supercapacitors, Xiao-Gang Zhang Oct 2017

Special Issue On Supercapacitors, Xiao-Gang Zhang

Journal of Electrochemistry

/


Electrochemical Capacitors Based On Anion-Graphite Intercalation Compounds, Hong-Yu Wang, Hui Fan, Xiao-Hong Wang, Li Qi Oct 2017

Electrochemical Capacitors Based On Anion-Graphite Intercalation Compounds, Hong-Yu Wang, Hui Fan, Xiao-Hong Wang, Li Qi

Journal of Electrochemistry

Anions can be electrochemically intercalated into a graphite electrode with a reversible capacity as high as 120 mAh·g-1 at the high potential near 5 V vs. Li/Li+. Besides, graphite is environmentally benign, economic and abundant in China. Therefore, graphite is a very promising positive electrode material for asymmetric capacitors using non-aqueous electrolytes. However, the performance of graphite positive electrode is quite sensitive to various affecting factors, such as the compositions of electrolyte solutions, graphite type and ambient temperature, and so on. In the platform of activated carbon/graphite capacitors, the electrochemical behavior of anion-graphite intercalation compounds can be …


Strategies To Enhance Energy Density For Supercapacitors, Jun-Wei Lang, Xu Zhang, Ru-Tao Wang, Xing-Bin Yan Oct 2017

Strategies To Enhance Energy Density For Supercapacitors, Jun-Wei Lang, Xu Zhang, Ru-Tao Wang, Xing-Bin Yan

Journal of Electrochemistry

The biggest advantage of supercapacitor lies in not only the excellent pulse and fast charging-discharging performance, but also the characteristics of long cycle life and wide operating temperature window with no pollution. However, the energy density of supercapacitor is low. In this paper, the working principle, the development status, defects and improvement method of supercapacitors are introduced. Based on the research workes of the supercapacitors with high energy density in our group, combined with the literature reports in recent years, the strategies to promote the energy density of supercarpacitors will be focused. The strategies for the enhancement of energy density …


Attempts To Improve The Energy Capacity Of Capacitive Electrochemical Energy Storage Devices, Lin-Po Yu, George Z. Chen Oct 2017

Attempts To Improve The Energy Capacity Of Capacitive Electrochemical Energy Storage Devices, Lin-Po Yu, George Z. Chen

Journal of Electrochemistry

This article reviews selected literatures from the authors’ research group on the development of capacitive electrochemical energy storage (EES) devices, focusing on supercapacitors and supercapatteries at both the electrode material level and device level. Electronically conducting polymers (ECPs) and transition metal oxides (TMOs) composited with carbon nanotubes (CNTs) were found to be able to improve the capacitance performance as capacitive faradaic storage electrode. Carbon materials, like activated carbon (Act-C) and carbon black, were used to fabricate non-faradaic capacitive storage electrode. It was found that the electrode capacitance balance can effectively extend the maximum charging voltage (MCV) of the supercapacitor, and …