Materials Science and Engineering Commons^™

Preparation And Performance Of Co And La Co-Doped Li-Rich Lithium Manganate, Da-Qiao Zhou

Journal of Electrochemistry

The cathode material of Li_1.1Co_0.02La_0.01Mn₂O₄ was successfully synthesized by the method of co-precipitation followed by a solid state reaction.In the sintering temperature range of 700～850 ℃,X-ray diffraction(XRD) results showed a single phase of each material and the increase of crystallization degree,and scanning electron microscopic(SEM) images indicated that the particle size increased and the specific surface area decreased,respectively,with increasing the sintering temperature.Due to its lower polarization resistance,the Co and La co-doped lithium-rich lithium manganate(sintered at 800 ℃) positive electrodes showed the most promising electrochemical performance.The capacity retention after 50 cycles reached 98.5%.

Electrochemical Properties Of Functionalized Carbon Nanotubes And Their Applications In Analysis Of 6-Mercaptopurine, Bao-Yi Lu, Yan-Yan Lai, Hong Li

Journal of Electrochemistry

The electrochemical behaviors and adsorption properties of single-walled carbon nanotubes such as SWNT,SWNT-COOH,and SWNT-OH and multi-walled carbon nanotubes including MWNT,MWNT-COOH,and MWNT-OH modified at a graphite electrode have been investigated by using [Fe(CN)₆]^3-anion and [Co(phen)₃]³⁺ cation.It was shown that shows good redox reversibility of [Fe(CN)₆]^3-/4-reactions on the existed carbon nanotubes(CNT) modified electrode.Based on the strong adsorptive property of [Co(phen)₃]³⁺ on the CNT surface,the [Co(phen)₃]³⁺/CNT modified graphite electrode can be obtained by progressive potential sweeping and developed to monitor quantitatively 6-mercaptopurine(6-MP).The adsorption capacity of …

High Utilization Aupt Nanoparticles Supported On Mwcnts For Methanol Electro-Oxidation In Alkaline Medium, Xun Guo, Dao-Jun Guo, Xin-Ping Qiu, Li-Quan Chen, Wen-Tao Zhu

Journal of Electrochemistry

We synthesized gold-platinum electrocatalysts supported on multi-walled carbon nanotubes(MWCNTs) with high utilization by a simple one-step method.A high Pt loading series of bimetallic AuPt/MWCNTs catalysts were prepared by the improved ethylene glycol reduction method,and then were compared in terms of the electrocatalytic activity for methanol electro-oxidation using cyclic voltammetry(CV) and chronoamperometry in alkaline solutions.The structure of AuPt/MWCNTs was characterized by the transmission electron microscopy(TEM),X-ray diffraction(XRD) and energy-dispersive X-ray spectroscopy(EDS).The results showed that the AuPt/MWCNTs catalysts had high Pt utilization,uniform AuPt nanoparticles size and good electrocatalytic activity for methanol electro-oxidation.The effect of Au/Pt mass ratio on electrocatalytic activity was also investigated.The …

Preparation And Electrochemical Performance Of Li3V2(Po4)3, Hou-Gang Fan, Tao Jiang, Chun-Zhong Wang, Gang Chen, Ying-Jin Wei

Journal of Electrochemistry

The carbon coating Li₃V₂(PO₄)₃ powder samples were synthesized by carbon incorporation solid state reaction.The structure,morphology and electrochemical properties have been studied by X-ray powder diffraction,scanning electron microscopy and automatic battery tester system,respectively.Carbon coating on Li₃V₂(PO₄)₃ would prevent the particles from agglomerating,reduce the particle size,raise the conductivity and improve the samples′ electrochemical performance.

Silicon Nanowires As Anode Materials For Lithium Ion Batteries, Yan-Peng Fu, Hui-Xin Chen, Yong Yang

Journal of Electrochemistry

The SiNWs electrodes were fabricated by coating and direct growth methods,respectively.The structure,morphology and electrochemical performance of such materials were characterized by XRD,SEM and charge-discharge tests.The results show that the electrodes prepared by direct growth method had higher capacity,better battery life and also displayed and excellent cyclability at higher currents.During the process of lithiation,the initial crystalline Si transformed to amorphous LixSi,and the average diameter of the SiNWs increased.Despite the large volume changed,the SiNWs remained intact and did not break into smaller particles.

Electrocatalytic Reduction Of Oxygen On Tungsten Carbide Electrode, Chun-An Ma, Yun Huang, Ying-Hong Zhu, Zhao-Yang Chen

Journal of Electrochemistry

Tungsten carbide(WC) catalysts were prepared by gas-solid reaction using ammonium metatungstate as precursors which were pretreated with spray drying sphere miniaturation,carbon monoxide as carrier gas and hydrogen as deoxidizing gas.The WC electrode was fabricated using WC catalyst powders and PTFE as binding agent,and characterized by XRD and SEM.Electrocatalyst behavior of WC for oxygen reduction reaction in the sulphuric acid solution was studied by steady-state voltammetry and cyclic voltammetry.The results show that the WC powders obtained were in spheric particles and the prepared WC electrode had a good electrocatalyst activity to the oxygen reduction reaction.The electrode reaction was controlled by adsorption.The …

Nano-Sn/Hard Carbon Composite As Anode Material For Lithium Ion Batteries, Bing-Kun Guo, Jie Shu, Kun Tang, Ying Bai, Zhao-Xiang Wang, Li-Quan Chen

Journal of Electrochemistry

The tin(Sn) nano particles were embedded into the mesopores of hard carbon spherules(HCS) to form a composite anode material for lithium ion batteries.The structure of the obtained composite was characterized by X-ray diffraction(XRD) while its electrochemical performances were evaluated with galvanostatic cycling.It is found that the embedding Sn nanoparticles into porous HCS not only result in a composite material with high lithium storage capacity and capacity retention,but also increase the initial coulombic efficiency of the composite.Based on the infrared spectroscopic analysis,the enhanced initial coulombic efficiency is attributed to the inductive decomposition of the ROCO₂Li species in the solid …

19th International Symposium Of Fine Chemistry And Functional Polymers (Fcfp-Xix) & Iupac 5th Internaitonal Symoposium On Novel Materials And Synthesis (Nms-V), Editorial Office Of J.Electrochem.

Journal of Electrochemistry

No abstract provided.

Preparation Of The Protic Ionic Liquid/Pvdf-Hfp Composite Membranes And Its Performance For Dmfc, Rui-Ying Miao, Jian-Ling Li, Yong Fang, Xin-Dong Wang

Journal of Electrochemistry

The protic ionic liquid(PIL) α-methyl pyridinium trifluoroacetate([α-MPyH]Tfa) was synthesized by acid & alkali neutralization.Then PIL/PVDF-HFP composite membranes were prepared by means of phase inversion method using acetone as solvent.The conductivities of the composite membrane increased with the temperature and reached 8×10^-3 S/cm,1×10^-2 S/cm and 3×10^-2 S/cm at room-temperature,30 ℃ and 80 ℃,respectively,by electrochemical impedance method.The properties of the methanol-rejecting of the membranes were measured by chronoamperometry as well.The results indicate that the properties of methanol-resistance of the membranes before and after IL combination were equivalent approximately.

Synthesis,Characteristics And Electrochemical Performance Of Nano-Sized Snco/Graphite Composites As Anode For Lithium Ion Batteries, Jin-Shu Cai, Ling Huang, Fu-Sheng Ke, Shi-Gang Sun

Journal of Electrochemistry

The nano-structural Sn-Co/graphite composites were prepared by chemical reduction of the alloy electroless deposition solution in graphite suspensions, and the composites were annealed at 500 ℃. The phase structure and surface morphology of the composites were measured by XRD, SEM and Raman. The results indicate that there were high dispersions and high loadings of Sn-Co nanoparticles on graphite by thermal treatment. Electrochemical lithium storage performance was studied preliminarily on the obtained samples. The graphite modified with the Sn-Co nanoparticles possessed a higher electrochemical reversible capacity than that of graphite during the charge and discharge process. The appetency between the Sn-Co …

Mesoporous Carbon For High Power Supercapacitors, Bin Xu, Lu Peng, Guo-Qing Wang, Gao-Ping Cao, Feng Wu, Yu-Sheng Yang

Journal of Electrochemistry

Mesoporous carbon for supercapacitors was prepared from sucrose using nano-CaCO₃ as template.The microstructure of the carbon was characterized with N₂ adsorption and transmission electron microscopy(TEM) observation.The electrochemical performances were evaluated in 6mol·L^-1 KOH aqueous electrolyte with galvanostatic charge/discharge,cyclic voltammetry,and ac impedance spectroscopy.The sucrose-based mesoporous carbon had a surface area of 606 m²/g and enriched mesopores in the range of 10～30 nm.The mesoporous carbon presented a specific capacitance of 125 F/g at a current density of 50 mA/g and outstanding excellent rate performance.As the current density increased to 20 000 mA/g,its capacitance remained at 88 F/g,much …

Preparation And Performance Of The Thin-Film Libpon Electrolyte, Feng Wu, Ya-Dong Liu, Ren-Jie Chen, Shi Chen

Journal of Electrochemistry

The LiBPON thin-film electrolyte was prepared by magnetron sputtering,and the relationship between the performance and the deposition condition was investigated.As seen in the SEM images,the thin films are dense and uniform without cracks,and according to the XRD patterns they have an amorphous structure.The electrochemical performance of the electrolyte was characterized by electrochemical impedance spectroscopy(EIS).The ionic conductivities of the thin film decreased with the RF power,but increased with the N₂ pressure.The an ionic conductivity of 3.5×10^-6 S/cm at room temperature was found from the electrochemical measurement.While the deposition rate increased with the RF power,but decreased with the N_{2 …}

Photoelectrochemical Properties Of Tio2 Nanoparticles, Jie Qu, Ying Li, Qi-Wei Jiang, Xue-Ping Gao

Journal of Electrochemistry

The protonated titanate nanoparticles were obtained at room temperature and subsequently calcined at different temperatures(300 ℃,400 ℃,500 ℃,600 ℃ and 700 ℃) in air.The obtained products were characterized by XRD,TEM and UV-Vis.It is found that the grain sizes of TiO₂ nanoparticles calcined at 300 ℃ were about 20 nm,and increased gradually with the temperature rise.Photoelectric performance was measured with I～V curve and electrochemical impedance spectroscopy(EIS).The TiO₂ nanoparticles obtained at 500 ℃ showed the best photoelectrochemical properties with a photovoltaic conversion efficiency of 6.39%,which is much higher than those at other temperatures.In addition,it is also demonstrated that the charge …

Electrooxidation Behaviors Of Tib2 As High Capacity Anodic Material In Neutral Aqueous Electrolytes, Ya-Dong Wang, Xian-Yong Guang, Zhi-Xin Wang, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

Titanium diborides were investigated as an anodic material for neutral aqueous batteries. It is revealed that this material shows superiorly high electrochemical activities in the neutral electrolytes. The discharge capacities observed for TiB₂ reached 1300 mAh/g at the constant current density of 50 mA/g, exceeding all the metal electrodes reported so far. The electrooxidation of this compound was found to proceed via the electrochemical dissolution of boron to form borofluoride, while titanium remained unchanged at the electrode. These results suggest a possible use of the boride compounds as a new material for constructing neutral aqueous batteries with high electrochemical …

The Electrochemical Performance Of Ncf-Sulfur Cathode, Chun-Rong Zhao, Zhong-Bao Yu, Wei-Kun Wang, Yu-Sheng Yang

Journal of Electrochemistry

The electrochemical performance of NCF-sulfur cathode, with different NCF contents, was investigated by constant current discharge, cyclic voltammetry and AC impedance methods. The morphologies of the cathodes were observed using scanning electron microscopy. The results indicate that the cycle life and rate capability of NCF-sulfur cathode increased. Better performance of sulfur cathode was obtained by 3% and 5% NCF conductive addition. When the current density was 0.4 mA/cm², the 3% NCF-sulfur cathode had an initial capacity of 880 mAh/g and a reversible capacity of 630 mAh/g after 20 cycles.

Electrosynthesis Of 2,2-Dimethylolpropionic Acid, Hong-Yan Sun, Zhen-Hai Liang

Journal of Electrochemistry

The Ti/SnO₂+Sb₂O₄/PbO₂ electrode was prepared.The structure phase and valent state were characterized by means of XRD and XPS.The 2,2-dimethylolpropionic acid was synthesized on the Ti/SnO₂+Sb₂O₄/PbO₂ anode by direct electro-oxidation of 2,2-dimethylolpropionaldehyde.The product and crude material were analyzed by HPLC,the effects of the concentration of 2,2-dimethylolpropionaldehyde,pH,potential and reaction temperature were studied.The results showed that the optimum conditions were anode potential 1.8 V,pH=1,reaction temperature 15 ℃ and 2,2-dimethylolpropionaldehyde concentration 0.10mol/L.Under the optimum conditions,the selectivity of 36%,the current efficiency of 28% and the conversion of 58% were reached.The reported …

Spectroscopic Investigation Of Palladium-Copper Bimetallic Systems For Pem Fuel Cell Catalysts, Timo Hofmann

UNLV Theses, Dissertations, Professional Papers, and Capstones

One of the main barriers to commercialization of polymer electrolyte membrane fuel cells systems is cost, which is largely due to the need of platinum (Pt)-containing catalysts. In this thesis we investigate bimetallic systems consisting of a base metal (copper) and a noble metal (palladium) that, as an alloy on the nanoscale, mimic the electronic properties that make Pt desirable as a catalyst.

We present a detailed investigation of the electronic structure of carbon-supported Pd/Cu nanoparticle catalysts, model bilayer thin film systems, alloys, and various metal reference samples. We have investigated the valence band structure of the catalysts using a …

Primary Study Of Tiron As Active Materials For The Redox Flow Battery, Yan Xu, Yue-Hua Wen, Jie Cheng, Yu-Sheng Yang, Zi-Li Xie

Journal of Electrochemistry

Effects of solution pH on the electrochemical behavior of tiron(sodium 4,5-dihydroxy-1,3-benzendisulfonic) couple(on a graphite electrode) were studied by cyclic voltammetry in aqueous solutions.It is shown that at pH<4,tiron exhibited a redox process at a relatively high potential with a good reversibility.A redox flow battery was formed employing tiron as the positive active species and V(III)/V(II) as the negative redox couple.In sulfuric acid medium,the coulombic efficiency of the tiron-V redox flow cell was more than 90% with a good cycle life.The decay in the cycle performance was minimal.Therefore,the feasibility of tiron as active materials for redox flow battery application is demonstrated.

Study On The Texturization Of C-Si Wafers By Different Kinds Of Alkaline For Heterojunction Solar Cells, Yu-Hua Dou, Yu-Qin Zhou, Mei-Fang Zhu, Shuang Song, Feng-Zhen Liu, Jin-Long Liu, Zhan-Jun Zhang

Journal of Electrochemistry

The texturization of(100) crystalline silicon(c-Si) wafer was studied by field-emission scanning electron microscope using different kinds of etchant: sodium hydroxide,sodium carbonate and tribasic sodium phosphate.By optimizing the etching parameters,the lowest values of averaged reflectance(Rav) were obtained to be 9.70% for NaOH,9.76% for Na₂CO₃ and 8.63% for Na₃PO₄·12H₂O,which is comparable to that of the wafer with textured surface covered with an anti-reflection coating of either silicon nitride or thermally grown silicon dioxide.The relation of Rav and surface morphology of textured wafer was analyzed.Moreover,special emphasis was put on the role of isopropyl alcohol(IPA) …

The Hydrothemal Synthesis Of Nanoscale Lifepo4 And Its Electrochemical Performance, Si-Min Wang, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

The cathode materials of LiFePO₄ were prepared via a hydrothermal reduction method using FeCl₃ as Fe source and iron as a reducing agent.The results showed that ferric salt could be reduced to ferrous salt completely under the hydrothermal condition and pure-phase LiFePO₄ was obtained based on the test results of XRD and FTIR. Carbon-coated LiFePO₄ was synthesized by pyrolysisng glucose at high temperature. The morphologies of pure LiFePO₄ displayed cluster-like while the LiFePO₄/C displayed sphere-like particles. The electrochemical test showed that the LiFePO₄/C had good rate performance,while LiFePO₄ delivered much …

Combustion Product Characterization Of The Iron-Heated Powders In Thermal Batteries, Jin Chong, Xue-Ping Gao, Ji-Qiang Wang

Journal of Electrochemistry

The combustion products of thermal battery used iron-heated powders have been studied.It is identified by X-ray diffraction (XRD) analysis that the main compositions of the combustion products are Fe, FeO and KCl. The transmission electron microscopy(TEM) shows a typical core-shell structure with un-reacted Fe particle core coated by FeO shell with a shell thickness of around 200 nm. The combusted iron-heated powders exhibit no metal property, which is contrast to previous assumption. Further measurement indicates that at the ambient temperature the combustion products show semiconductor property of the p-type with conductivity in the order of 103 S·cm^-1, which …

Synthesis Of The Lifepo4 By Co Reduction: Reaction Mechanism And Kinetics, Yun-Hua Chen, Yong Yang

Journal of Electrochemistry

LiFePO₄ cathode material was synthesized by CO reducing FePO₄ and LiOH precursors.The structure,morphology and electrochemical performances of such LiFePO₄ material were characterized by XRD,SEM and charge-discharge tests.It was shown that the particle size of the LiFePO₄ synthesized with 5% excess of LiOH in the precursor was about 200 nm.By carbon coating,the LiFePO₄ electrode was able to deliver a reversible capacity of 158 mAh·g^-1 at 0.1C discharge rate.Temperature-programmed X-ray diffraction was employed to monitor the reaction during the formation of LiFePO₄,and Li₃Fe₂(PO₄)₃ was found to be …

Preparations Of Composite Electrodes Of Pt With HXWo3 And Catalytic Activity Toward Oxygen Reduction Reaction, Pan-Pan Guo, You-Ju Huang, Hong-Yan Yang, Wei Li, Qing-Long Zhang, Wei-Shan Li

Journal of Electrochemistry

Three composite electrodes of platinum with hydrogen tungsten bronze(H_xWO₃)were prepared by voltammetry: hydrogen tungsten bronze deposited on platinum(H_xWO₃/Pt);platinum deposited on hydrogen tungsten bronze(Pt/H_xWO₃) and codeposited platinum and hydrogen tungsten bronze(Pt-H_xWO₃).The eletro-catalytic activities of three electrodes toward oxygen reduction reaction were studied.It is found that the catalytic activity of platinum can be improved by introducing with hydrogen tungsten bronze.Among these composite electrodes Pt/H_xWO₃,and the electrode shows the best eletro-catalytic activity toward oxygen reduction reaction,hence,provides a new way for reducing loading of …

High Performance Fuel Cell Catalyst And 5kw Pemfc Stack Without Humidification At Room Temperature And Atmosphere, Xin-Fa Hu, Min Chen, Shi-Jun Liao

Journal of Electrochemistry

The Pt/C catalyst with high dispersion and high performance was prepared successfully by an organic colloidal method and small batch production(10g) of Pt/C catalyst has been realized.The particle sizes of the active components in the catalyst could be as small as 2.8 nm and the active surface area was up to 450 m²/g.A high performance membrane-electrode assembly(MEA) with surface area of 275 cm² has been prepared by using the home-made catalyst with a catalyst coated membrane method invented in the lab,and a 5 kW stack has been assembled.The stack showed working 10 h at room temperature,atmosphere and …

Ec-Pt/Cnts Glucose Oxidative Electrode, Jia-Hua Liang, Chun-Mei Zhou, Hong-Juan Wang

Journal of Electrochemistry

A glucose oxidative electrode(GOD),EC-Pt/CNTs glucose oxidative electrode,was constructed by ethyl cellulose(EC) and Pt/CNTs.The sensitivity of the EC-Pt/CNTs GOD is 0.85 μA/mM in the concentration range of 0～4 mmol/L of glucose.After dipped in PBS(4℃) for 18 days,the activity of the EC-Pt/CNTs GOD can reach 80%.It is promising for the EC-Pt/CNTs GOD to be used to construct glucose biosensor.

Voltammetric Determination Of Iodate Ion In Table Salt By Carboxylic Carbon Nanotubes Modified Carbon Paste Electrode, Jun-Hua Li, Fu-Xing Zhang, Jian-Qiu Wang, Zhi-Feng Xu, Rong-Ying Zeng, Yan Yu

Journal of Electrochemistry

A highly-sensitive and mercury-free method of determining iodate ion in table salt was established based on carboxylic carbon nanotubes modified carbon paste electrode.In 0.1 mol/L NaOH solution,there was a sensitive cathodic stripping peak on voltammograms.The stripping peak potential was-0.52 V when accumulation time of IO-3 at the modified electrode was 60 s and the potential scan rate was 300 mV/s.There was a good liner relationship between the peak current and IO-3 concentration in the range of 8.0×10^-10 ～ 5.0×10^-8 mol/L and 1.0×10^-7 ～ 3.0×10^-6 mol/L with the correlation coefficient of 0.999 and 0.998,respectively.The detection limit was …

Electrochemical Behavior And Determination Of Paracetamol On Activated Glassy Carbon Electrode, Bao-Yu Tan, Fang Liao, Xiao-Ying He, Qing-Tao Zhu, Jun Hua, Xiao-Li Jiang

Journal of Electrochemistry

The electrochemical behavior of paracetamol(PCT) was studied at glassy carbon electrode activated by cyclic voltammetry.In HAc-NaAc buffer solution(pH=4.00),a couple of sensitive redox peaks were recorded about 0.54 V in the cyclic voltammograms.The result indicated that the process was controlled by adsorption and nearly reversible.The reaction electron and proton numbers were estimated,respectively,to be two.Excllent linearity was observed in the correlation between the oxidation peak current and the concentration of PCT in the range of 8.00×10^-6～2.00×10^-4 mol·L-1.The correlative coefficient was-0.999 18.The detection limit was 6.34×10^-6 mol·L^-1.This method can be used for the determination of PCT real …

Fabrication Of Superhydrophilic Aluminum Oxide Through Single-Step Anodic Oxidation, Qin Zhang, Qi-Ming Yin, Jia-Ming Ye, Yuan-Rong Zhu

Journal of Electrochemistry

Hydrophilic aluminum oxide is popularly used for heat exchanger of air-condition.Herein,we developed a simple method to prepare superhydrophilic aluminum oxide on the surface of aluminum through single-step electrochemical oxidization.The morphologies and water contact angles on surfaces of alumina fabricated under different electrochemical conditions were investgated.Superhydrophilic surfaces fabricated by this method have good stability and high mechanical strength with water contact angle almost 0°.Coated with low surface energy materials,superhydrophilc alumina will be converted to superhydrophobic.

Voltammetric Determination Of L-Cysteine At Bipyrine Bridged Copper(Ⅱ) Complex Modified Glassy Carbon Electrode, Ming-Yan Wang, Fan Yang, Sheng-Yu Zhang, Xing-You Xu, Xu-Jie Yang

Journal of Electrochemistry

A modified electrode has been constructed by depositing a novel copper(Ⅱ) complex 2biPy(ClO₄)₄ on the glassy carbon electrode through the method of cyclic voltammetry(CV).It was found that the modified electrode exhibited high electrocatalytic activity toward L-Cysteine oxidation with good reproducibility and high sensitivity.The peak current of semi-derivative linear scan was proportional to the concentration of L-cys in the range of 1×10^-6～3×10^-4 mol·L^-1.The detection limit was 5×10^-7 mol·L^-1.

Preparation And Electrocatalystic Performance Of Ir/C Catalyst For Ammonia Oxidation, Qing-Mei Kong, Yi-Ping Han, Ling-Juan Deng, Tian-Hong Lu, Ya-Wen Tang

Journal of Electrochemistry

The Ir/C catalyst with 30%(by mass) Ir was prepared in the CH₃CH₂OH and H₂O binary system.The X-ray diffraction(XRD) data showed that the average sizes of the Ir particles in the Ir/C catalyst was about 2.2 nm.The results of the electrochemical measurements indicated that the electrocatalytic activity of the Ir/C catalyst for the ammonia oxidation in the neutral NaClO₄ solution was similar to the Ir catalyst,while electrocatalytic stability was much better than that of the Ir catalyst.Furthermore,the peak current density of the ammonia oxidation at the Ir/C catalyst electrode showed a good linear relationship …