Engineering Science and Materials Commons^™

Preparations And Applications Of Layered Carbon And Layered Carbon-Pbso4 Composite, Shu-Kai Zhang, Hao Zhang, Wei-Hua Xue, Jie Cheng, Wen-Feng Zhang, Gao-Ping Cao, Hai-Lei Zhao, Yu-Sheng Yang

Journal of Electrochemistry

The layered carbon materials (similar to graphene) have been synthesized by chemical vapor deposition (CVD) on the cheap catalyst (potassium or sodium carbonate substrate). The layered-carbon- lead sulfate (PbSO₄) composite could be prepared by in situ chemical deposition based on the layered carbon. The XRD, SEM and TEM results showed that the layered carbon materials was amorphous carbon layer, and the composite was a compound made of fine lead sulfate grains and layered carbon. Thermogravimetric analysis determined the carbon content in the composite. Adding a certain amount of layered carbon or layered-carbon-PbSO₄ composite into negative active materials …

Preparation Of Zro2-Doped Nb/Pbo2 Electrode And Electrocatalytic Performance Of Methyl Orange Degradation, Li Zhang, Wen-Yan Dong, Tai-Lai Yang, Zhen-Hai Liang

Journal of Electrochemistry

The zirconium oxide (ZrO₂)-doped niobium based lead oxide (Nb/PbO₂) electrode was prepared by electrodeposition. The microstructures and electrochemical properties of Nb/ZrO₂+PbO₂ electrode were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), linear sweep voltammetry, electrochemical impedance spectroscopy and cyclic voltammotry. In addition, the Nb/PbO₂ electrode was used as an anode for the electrochemical degradation of methyl orange (MO). Results revealed that the ZrO₂ doping made the Nb/PbO2 electrode surface denser and rougher with smaller sized crystal particles, which increased the specific surface area and enhanced the electrocatalytic activity of the …

Electrochemical Mass Spectrometric Study Of Lithium-Oxygen Batteries, Xin-Xiu Yan, Li-Po Ma, Zhang-Quan Peng

Journal of Electrochemistry

Mass Spectrometry, coupled with electrochemistry, is a powerful research tool to study mechanisms for a broad range of electrode reactions by identifying and quantifying reaction products and intermediates. In this review, we summarize the recent advances in the Li-O₂ battery researches offered by electrochemical mass spectrometry based on our group investigations. These include the research progresses in electrolytes, cathode materials (electrocatalysts), and parasitic reactions, i.e., the key issues associated with Li-O₂ research. In addition, we also discuss the effects of irreversible side reactions involved in battery systems on charge and discharge processes.

Synthesis Of Graphene Wrapped Li-Rich Layered Metal Oxide And Its Electrochemical Performance, Meng-Yan Hou, Ke Wang, Xiao-Li Dong, Yong-Yao Xia

Journal of Electrochemistry

In present work, lithium-rich layered transition metal oxide (LLO) was synthesized by a co-precipitation method in combination with a solid-state reaction. The graphene wrapped Li-rich layered oxide composite (LLO/Gra) was obtained by sintering the LLO/GO composite at 300 ^oC for 30 min in an air. The morphologies and the electrochemical performances were characterized by means of SEM, TEM, XRD, XPS, EIS and charge/discharge tests. The results indicated that the LLOe particles were uniformly wrapped with graphene. The resulting material exhibited better rate capability than that of pristine LLO since the wrapped graphene demonstrated the enhanced electronic conductivity. Accordingly, the …

Research Progress In Carbon Coating On Lifepo4 Cathode Materials For Lithium Ion Batteries, Ning Zhang, Yong-Chang Liu, Cheng-Cheng Chen, Zhi-Qiang Zhu, Zhan-Liang Tao, Jun Chen

Journal of Electrochemistry

Olivine-structured LiFePO₄ has been received much attention because of its flat voltage profile, low cost, abundant material supply and better environmental compatibility. However, the poor electronic and ionic conductivities have limited its application in industry. One of the best methods to improve the electrochemical performance is carbon coating. In this review, we summarize the recent developments of LiFePO₄/C cathode. Moreover, the different effects caused by coating methods and carbon sources, as well as the mechanism of carbon coating on the properties of LiFePO₄/C are reviewed.

Enhancing Stability Of Pem Fuel Cell Catalysts Via Support Changing, Xiao-Hong Xie, Zi-Dong Wei

Journal of Electrochemistry

The Pt/C catalyst with highly dispersed Pt nanoparticles supported on carbon has been widely used as the state-of the-art catalyst in proton exchange membrane fuel cells (PEMFCs), while the durability of Pt/C is one of the major barriers for large-scale applications of PEMFCs. Thus, enhancing the stability of Pt/C has been a hot issue in this field. In this review, we summarize the recent progress in enhancing the catalyst stability in the view of support material. The future prospects of the PEMFCs catalyst should focus on adopting more stable supports or strengthening the interactions between Pt and supports.

Pt/C Modified Proton Exchange Membrane For Improved Fuel Cell Performance, Zhi Cui, Chao Wang, Shui-Yun Shen, Feng-Jing Jiang, Jun-Liang Zhang

Journal of Electrochemistry

The property of proton exchange membrane greatly affects the performance of proton exchange membrane fuel cells (PEMFC). During the operation of a PEMFC, the water produced at the cathode, the water vapor from the humidified feed gas and the water migrated by electro-dragging will reach a balance in the membrane and determine the resistance of PEMFC, and thus affect the performance of PEMFC. Normally, the PEMFC performance strongly depends on the relative humidity of the feed gas, and the performance decreases at lower humidity as a result of lower proton conductivity of the membrane. In this paper, we proposed to …

Electrolytes For Lithium And Lithium-Ion Batteries, Zong-Rang Zhang

Journal of Electrochemistry

This is an up-to-date book published by Springer last year and focuses on the field of the electrolytes for lithium and lithium-ion batteries. A brief introduction and review of this book are given in this paper. The main contents of this book are introduced briefly in the order of ten different chapters along with a short review of recent progress in those fields.

Lithium Air Batteries: Non-Aqueous And Hybrid Systems, Sheng-Fu Tong, Ping He, Xue-Ping Zhang, Shi-Yong Zhao, Hao-Shen Zhou

Journal of Electrochemistry

Developing energy storage devices and new materials, which match the requirements in electric vehicles (EVs) and hybrid electric vehicles (HEVs), is an effective way to balance the contradiction between the social development and the shortage of fossil energy and environment pollution. Rechargeable lithium-air (Li-air) batteries consisting of Li and oxygen as the anodic and cathodic reactants, respectively, have attracted much attention during the past decade due to their high theoretical specific energy. According to work conditions, the most studied types of Li-air batteries are non-aqueous, hybrid, and solid state electrolyte Li-air batteries. Challenges still exist in cathodes, anodes, electrolytes and …

The Effect Of Noise On The Response Of A Vertical Cantilever Beam Energy Harvester, Michael I. Friswell, Onur Bilgen, S. Faruque Ali, Grzegorz Litak, Sondipon Adhikari

Mechanical & Aerospace Engineering Faculty Publications

An energy harvesting concept has been proposed comprising a piezoelectric patch on a vertical cantilever beam with a tip mass. The cantilever beam is excited in the transverse direction at its base. This device is highly nonlinear with two potential wells for large tip masses, when the beam is buckled. For the pre-buckled case considered here, the stiffness is low and hence the displacement response is large, leading to multiple solutions to harmonic excitation that are exploited in the harvesting device. To maximise the energy harvested in systems with multiple solutions the higher amplitude response should be preferred. This paper …

High Pressure Behavior Of Mullite-Type Oxides: Phase Transitions, Amorphization, Negative Linear Compressibility And Microstructural Implications, Patricia Kalita

UNLV Theses, Dissertations, Professional Papers, and Capstones

Even though mullite occurs rarely in nature, it is perhaps one of the most important phases in both traditional and advanced ceramics. Existing and emerging applications of mullite and mullite-type materials include: high-temperature composites, aerospace materials, ballistic shielding for military applications and even non-linear optical materials. There are many uncertainties regarding the basic physical properties of mullite-type materials, particularly in terms of their high-pressure structural stability and mechanical behavior that are important to address for emerging applications of mullites as engineering materials. This work is the first reported comprehensive investigation of the high –pressure structural behavior of several different mullites …

Researches On In-Situ And Ex-Situ Characterization Techniques In Lithium Batteries, Wen-Jun Li, Jie-Yun Zheng, Lin Gu, Hong Li

Journal of Electrochemistry

Electrochemical performance of Lithium batteries is directly linked to interfacial transports, reactions and storing behaviors of electrons and ions at bulk-surface interfaces. It is extremely important to conduct evolution studies from atomic level to macro level in electron structures, crystal structures, microstructures and morphologies, chemical compositions and physical properties of battery materials at equilibrium and nonequilibrium in order to understand various structure-performance relations in lithium ion batteries. Advanced in-situ and ex-situ characterization techniques have been used widely to clarify scientific and technological problems in lithium batteries. This paper summarizes our efforts on battery researches using various experimental techniques, including in …

Recent Research Progress For Non-Pt-Based Oxygen Reduction Reaction Electrocatalysts In Fuel Cell, Ping Song, Ming-Bo Ruan, Jing Liu, Guang-Jun Ran, Wei-Lin Xu

Journal of Electrochemistry

The expensive Pt-based catalyst suffers from its susceptibility to time-dependent drift, methanol crossover, and carbon monoxide (CO) deactivation, which will block the large-scale commercial application of fuel cells. It is, therefore, necessary to develop efficient, low-cost, highly stable non-precious metal oxygen reduction reaction (ORR) catalysts with high catalytic performance. Here, we will pay attention to the research progress of non-precious metal and heteroatom-doped (N, B, P, S, F) metal-free ORR catalysts. Importantly, we mainly focus on the work developed by Xu’s group with the Fe-based non-precious metal and F/NF-doped metal-free ORR catalysts. The purpose of these works is to improve …

Research Progress Of Mn-Based Lithium-Rich Cathode Materials For Li-Ion Batteries, Luo-Zeng Zhou, Qun-Jie Xu, Wei-Ping Tang, Xue Jin, Xiao-Lei Yuan

Journal of Electrochemistry

With rapid development of new energy industry like electric vehicles and energy storage station, these fields highly demand the next generation of high performance Li-ion battery systems with stronger energy density, higher power density, and longer cycling life. Lithium-rich Mn-based cathode materials, xLi₂MnO₃·(1-x)LiMO₂(M=Mn, Co, Ni...), have become the hot topic and drawn attentions of scholars worldwide because of their high reversible capacity exceeding 240 mAh·g^-1, excellent electrochemical properties, and low cost, which makes them most promising cathode material candidates for next Li-ion battery system. The cathode material Li[Li_0.2Mn_0.54Ni …

Preparation And Properties Of Binary Oxides CoXCr1-XO3/2 Electrocatalysts For Oxygen Evolution Reaction, Tai-Lai Yang, Wen-Yan Dong, Hui-Min Yang, Li Zhang, Zhen-Hai Liang

Journal of Electrochemistry

Binary metal mixed oxides of Co and Cr with nominal compositional formulas, Co_xCr_1-xO_3/2 (x=0, 0.2, 0.4, 0.6, 0.8 and 1.0), were obtained by thermal decomposition method. The morphologies, crystal forms and valence states of the catalyst powders were analyzed by SEM, XRD and XPS, respectively. And the electrochemical properties, overpotentials and stabilities of Co_xCr_1-xO_3/2 electrodes for oxygen evolution reaction (OER) in an alkaline solution were evaluated by linear sweep voltammetry (LSV), staircase voltammetry and chronoamperometry, respectively. The results indicated that the mixtures of Co₃O₄ and eskolaite-Cr_{2 …}

Synthesis And Electrochemical Properties Of Cnts/V2O5 Hollow Microspheres, Liang Hao, Lai-Fa Shen, Jie Wang, Jia-Jia Zhu, Xiao-Chen Zhao, Xiao-Gang Zhang

Journal of Electrochemistry

The carbon nanotubes/vanadium oxides (CNTs/V₂O₅) hollow microspheres (VOC) were prepared via solvothermal process. The effects of the ratio for CNTs to V₂O₅ on the morphologies, structures and electrochemical performances were systemically investigated. The results indicate that CNTs dramatically enhanced the rate performances of VOC composite electrodes. When the ratio of CNTs is 7.1%, the VOC composite electrode exhibited the best electrochemical performance, which delivered a specific capacitance of 346 F·g^-1 at 0.5 A·g^-1 and maintained 75% at 8 A·g^-1 in 5 mol L^-1 LiNO₃. A hybrid capacitor …

Electrochemical Performance Of Coal2O4-Coated Lini1/3Co1/3Mn1/3O2, Ji-Jun Cai, Wang-Jun Cui, Bing Li, Yang-Yang Yu, Jin-Bao Zhao

Journal of Electrochemistry

A method to improve the electrochemical performance of LiNi_1/3Co_1/3Mn_1/3O₂ for high voltage lithium-ion battery by CoAl₂O₄ coating was present in this work. The effects of CoAl₂O₄ coatings on the structure and electrochemical properties of LiNi1/3Co1/3Mn1/3O2 were investigated in detail. The results show that CoAl₂O₄ forms a thin layer of 8 nm on the surface of LiNi_1/3Co_1/3Mn_1/3O₂ without destroying the structure of the core material. The CoAl₂O₄-coated LiNi_1/3Co_1/3Mn_1/3O …

Porous Co3O4 Hollow Nanospheres Cathode Catalyst For High-Capacity And Long-Cycle Li-Air Batteries, Tong Liu, Na Li, Qing-Chao Liu, Xin-Bo Zhang

Journal of Electrochemistry

In this paper, a high specific surface area of porous Co3O4 hollow nanospheres was successfully synthesized via hydrothermal carbonization at 140 °C, followed by calcination using cobalt nitrate hexahydrate (Co(NO3)2·6H2O), hexamethylenetetramine (HMT), sucrose, and sodium citrate (Na3C6H5O7). The porous Co3O4 hollow nanospheres consisted of nanoparticles with high specific surface area of mesoporous structure, and could provide active reaction sites for OER and ORR. When used as lithium-air battery cathode catalyst, the Co3O4/Super P (SP) electrode exhibited excellent cycle performance, resulting in high capacity and long life of lithium-air batteries.

Electrodeposition Of Al-Mg Alloys From Acidic Alcl3-Emic-Mgcl2 Room Temperature Ionic Liquids, Rostomali M., P. Abbott Andrew, S. Ryder Karl

Journal of Electrochemistry

Electrodeposition of aluminium-magnesium alloys have been carried out onto platinum and copper cathodes from Lewis acidic aluminium(III) chloride-1-ethyl-3-methylimidazolium chloride ionic liquid containing magnesium(II) chloride by constant current and constant potential methods at room temperature. Magnesium content in the deposited alloy increases with increasing MgCl₂ concentration in the ionic liquid and with increasing cathodic current density. The influences of various experimental conditions on electrodeposition and the morphology of the electrodeposited layers have been investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDAX). On increasing the deposition current densities the dense, bright, adherent …

Syntheses And Electrochemical Performances Of Li4Ti5O12 Anode Materials For Lithium Ion Battery, Yong-Long Zhang, Xue-Bu Hu, Yao-Qiong Wang, Dong-Hai Huang

Journal of Electrochemistry

Series of spinel lithium titanate (Li₄Ti₅O₁₂) materials were synthesized by one-step solid-state reaction using lithium acetate and TiO₂ as raw materials under different temperatures (750/800/850 °C) and atmospheres (N₂/air). The as-prepared Li₄Ti₅O₁₂ materials were investigated by thermogravimetric analysis, X-ray diffraction, scanning electron microscopy, cyclic voltammotry and charge-discharge test to analyze their crystal structures, microstructures and electrochemical performances. The results show that the Li₄Ti₅O₁₂（L-800N）material obtained at 800 °C under nitrogen atmosphere exhibited better electrochemical performance and smaller particle size. The initial …

A Platinum-Hydrogen Reference Micro-Electrode For All Vanadium Redox Flow Battery, Zhi-Bin Lin, Yan-Qing Dong, Ming-Sen Zheng, Quan-Feng Dong

Journal of Electrochemistry

A platinum-hydrogen reference micro-electrode was made with electroplating Pd on the surface of Pt wire and then coating anion membrane material. This reference electrode was built-in the porous electrode of the all vanadium redox flow batteries (VRFB), and monitored the charging /discharging and self-discharging of the VRFB. The results indicated that the capacity fading of VRFB occurred due to the graduate reduction of V(IV) active species in the electrolyte and the accumulation of V(V) in the positive electrode, leading to nonequilibrium of active species between the positive and negative electrodes.

Electrochemical Conversion Reactions And Their Applications For Rechargeable Batteries, Ting Li, Han-Xi Yang

Journal of Electrochemistry

Electrochemical conversion reactions have received considerable interest as a new redox mechanism for constructing high capacity electrodes of rechargeable batteries. Without strict restrictions on the crystalline structure of the host lattice and the size of the associated ions, conversion reactions can take place in a variety of different metal compounds with different metal cations and deliver much higher reversible capacities through full utilization of all the oxidation states of the transition-metal compounds, opening up a new avenue for developing high capacity materials of rechargeable batteries. This paper briefly reviews the state of the art and challenges of conversion electrodes and …

Intensity And Resolution Enhancement Of Local Regions For Object Detection And Tracking In Wide Area Surveillance, Evan Krieger, Vijayan K. Asari, Saibabu Arigela, Theus H. Aspiras

Electrical and Computer Engineering Faculty Publications

Object tracking in wide area motion imagery is a complex problem that consists of object detection and target tracking over time. This challenge can be solved by human analysts who naturally have the ability to keep track of an object in a scene. A computer vision solution for object tracking has the potential to be a much faster and efficient solution. However, a computer vision solution faces certain challenges that do not affect a human analyst. To overcome these challenges, a tracking process is proposed that is inspired by the known advantages of a human analyst.

First, the focus of …

Electrochemical Monitoring Of Cell Wall-Regulated Transient Extracellular Oxidative Burst From Single Plant Cells, Jun-Tao Liu, Yan-Ling Liu, Zhi Cheng, Shi-Jing Chen, Wei-Hua Huang

Journal of Electrochemistry

Oxidative burst by rapid, transient generation of reactive oxygen species (ROS) is a fundamental process for plant disease defense and signal transduction. ROS can be protective or toxic depending on their concentrations, and critical balance between ROS production and scavenging is regulated by complex and perfect mechanisms in plant cells. However, the process of rapid and transient ROS burst from plant cells and their regulatory mechanisms are far from being completely understood, owing to the methodological obstacles in real-time monitoring such a fast process. In this work, we showed the application of microelectrode electrochemistry with high spatiotemporal resolution to monitor …

A Novel Nitrite Sensing Electrode Based On Au/Fe3O4/Chitosan Nanocomposite, Ying Dong, Yong Wang, Huan-Huan Xing, Jian-Ying Qu

Journal of Electrochemistry

A novel nitrite sensing electrode based on gold nanoparticles and iron oxides (Fe₃O₄) magnetic nanoparticles was fabricated with chitosan as the protective film on glassy carbon matrix. Experiment results showed that the sensing electrode exhibited good electrocatalytic activity toward oxidation of nitrite, and the oxidation peak current increased linearly with the concentration of nitrite varying from 5.0×10^-6 to 2.0×10^-3 mol·L^-1 (R=0.9996) with a detection limit of 7.1×10^-7 mol·L^-1 (S/N=3). The sensing electrode exhibited good sensitivity, selectivity and repeatability.

Electrochemiluminescence Assay Based On Bipolar Electrode For Bioanalysis, Mei-Sheng Wu, Jing-Juan Xu, Hong-Yuan Chen

Journal of Electrochemistry

Bipolar electrodes (BPEs) are electronic conductors which are usually embedded into microchannels. The potential difference at the BPE/solution interface is obtained by applying a voltage at the two ends of the microchannel. When it reaches a critical value, the redox reaction takes place at both poles of the BPE simultaneously. Compared with other detection methods, the electrochemiluminescence (ECL) platform based on BPE possesses the advantages of concentration enrichment, high sensitivity, low cost, portable sensor system, no need for a light source, which is quite suitable for bioanalysis. This paper reviews the ECL-BPE strategy for bioanalysis and proposes the future research …

An Enzymatic Ethanol/O2 Biofuel Cell Powered By Commercial Vodka Fuel, Yi-Ming Yan, Lan-Qun Mao

Journal of Electrochemistry

This study demonstrates the performance of a new type alcohol/O₂ biofuel cell assembled by using alcohol dehydrogenase (ADH) and bilirubin oxidase (BOD) as the biocatalysts of the bioanode and the biocathode for the bioelectrocatalytic oxidation of alcohol and reduction of oxygen, respectively. To construct the bioanode and the biocathode, single-walled carbon nanotubes (SWCNTs) were used. In the bioanode, SWCNTs were used as the supporting materials for both methylene green (MG) which was used as the electrocatalyst for the oxidation of NADH and ADH. The as-constructed MG/ADH/SWCNTs-based bioanode exhibits a good activity toward the bioelectrocatalytic oxidation of ethanol. In the …

Electrochemical Detection Of L-Cysteine Based On Iron Phthalocyanine/Nitrogen-Doped Graphene Modified Electrodes, Jing-Jing Xiao, Hui-Ying Xu, Li Xu, Bao-Hong Liu

Journal of Electrochemistry

In this study, we report a facile method to develop FePc/N-G hybrid modified electrode for the detection of L-cysteine. The electrochemical sensor was characterized by cyclic voltammetry and amperometric response. The sensor exhibited a wider linear range with rapid response which has outperformed pure FePc/GCE, highlighting the important role of nitrogen doped graphene as substrate for improving the electrochemical response property.

Nanosized Fe2O3 On Three Dimensional Hierarchical Porous Graphene-Like Matrices As High-Performance Anode Material For Lithium Ion Batteries, Qin-Wei Zhang, Yun-Yong Li, Pei-Kang Shen

Journal of Electrochemistry

Ferric oxide (Fe₂O₃) as a promising anode material for lithium ion battery is due to its high theoretical capacity (1007 mAh·g^-1), earth abundance and low cost. The nanosized Fe₂O₃ on the three dimensional hierarchical porous graphene-like network (denoted as Fe₂O₃-3D HPG) has been synthesized by homogeneous precipitation and heat treatment. The 3D HPG can provide a highly conductive structure in conjunction to support well contacted Fe₂O₃ nanoparticles, and effectively enhance the mechanical strength of the matrices during volume changes, as well as improve the …

Preparation And Properties Of Titanium Based Metal Oxide Electrodes For Ammonia Nitrogen Wastewater Treatment, Xue Li, Meng Xue, Ling Huang, Jun-Tao Li, Shi-Gang Sun

Journal of Electrochemistry

In this paper, four types of titanium based metal oxides electrodes were prepared by thermal decomposition method: Ti/SnO₂+Sb₂O₃, Ti/SnO₂+Sb₂O₃/SnO₂+IrO₂, Ti/SnO₂+Sb₂O₃/SnO₂+RuO₂, Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂. The XRD results show that CeO₂ in Ti/SnO₂+Sb₂O₃/SnO₂+CeO₂ displayed a good crystal structure, and there was no significant oxygen evolution reaction occurred after electrolytic oxidation. Compared with the other three electrodes, the Ce-doped …