Power and Energy Commons^™

Electrelectrochemical Performances Of C-Coating And Co-Doping Lifepo4, Ying Bai, Jue-Ming Yang, Chun-Bo Qing, Wei-Feng Zhang

Journal of Electrochemistry

Phospho-olivine LiFePO₄ cathode materials were prepared by hydrothermal reaction at 200 ^oC. Sucrose was added as C-coating resource and Co was doped into the crystal lattice of LiFePO₄. In order to investigate the improvements in the electrochemical properties of Co-doped LiFePO₄, three samples, LiFePO₄, C-coated LiFePO₄ and C-coating-Co-doped LiFePO₄, were synthesized under the same preparation conditions. Charge/discharge studies reveal that the Co-doped LiFePO₄/C composite annealed at 400 ^oC exhibits marked improvement of specific capacity by diminishing the particle sizes and enhancement in the degree of crystallinity. …

Study On The Electrochemical Behaviors Of Gc Electrode Modified With Carbon Nanotube-Polyelectrolytes And Its Application For Rutin Detection, Liang Hua, Xia-Qin Wu, Rong Wang

Journal of Electrochemistry

The electrochemical behaviors of rutin and ascorbic acid at single-wall carbon nanotube and polyelectrolytes (dimethyl-diallylammonium chloride, PDDA) film modified glassy carbon electrode was investigated. The cyclic voltammetric results showed that electron transfer of rutin at PDDA/SWCNTs/GC modified electrode is an adsorption-controlled process. The separation of oxidation peak potentials of rutin and ascorbic acid was more than 200 mV. The rutin concentration in the presence of AA were detected by differential pulse voltammetry (DPV). The experimental results indicated that the PDDA/SWCNTs/GC modified electrode can be used for the detection of rutin in the presence of high concentration of AA. The DPV …

Synthesis Of Limnpo4/C Used As Cathode Material For Lithium Ion Batteries, Xin Yang, Xue-Wu Liu, Gui-Chang Liu, Zhi-Cong Shi, Xin Li, Guo-Hua Chen

Journal of Electrochemistry

The LiMnPO₄/C composites were prepared using a solid-state reaction with addition of the resorcinol formaldehyde resin as the carbon source. The effects of reaction temperature and time on the crystal structure, morphology and electrochemical properties of the LiMnPO₄/C composites were investigated. The results show that the best performance was achieved with the LiMnPO₄/C composites synthesized at 600 ^oC for 12 h which had the particle sizes about 100~200 nm. The initial discharge capacities were 121.6 mAh·g^-1 at 0.02C, 110 mAh·g^-1 at 0.1C and more than 60 mAh·g^-1 at 1C. An …

Synthesis And Electrochemical Behaviors Of Li2Coxmn1-XSio4 As A Cathode Material For Lithium-Ion Batteries, Lin Wang, Dong-Ping Lv, Yong Yang

Journal of Electrochemistry

We have successfully synthesized Li₂Co_xMn_1-xSiO₄/C (x=0, 0.1, 0.3, 0.5, 1)/C composites using hydrothermal assisted sol-gel process and ball-milling method. The results of X-ray diffraction show that the solid solutions of Li₂Co_xMn_1-xSiO₄ can be achieved when x≤0.3. The initial capacities increase from 70 mAh·g^-1 of Li₂MnSiO₄/C to 105 mAh·g^-1 of Li₂Co_0.3Mn_0.7SiO₄/C. Cyclic Voltammetry (CV) curves show that the replacement of Mn with Co can reduce the electrochemical polarization, making the insertion-extraction reaction …

Morphology Changes In Pcpdtbt:Pcbm And P3ht:Pcpdtbt:Pcbm And Its Effect On Polymer Solar Cell Performance, Galen David Cauble

Physics

Polymer solar cell morphology is sensitive to both heat and time. By thermally annealing polymer solar cells the morphology of the devices can be altered causing immediate changes in device performance. Blending PCPDTBT:PCBM with P3HT:PCPDTBT combines the absorption characteristics of each to create a more even absorption spectrum. Subjecting PCPDTBT:PCBM, and P3HT:PCPDTBT:PCBM polymer solar cells to thermal annealing as well as recording device performance through time has shown that P3HT:PCPDTBT:PCBM devices react positively to thermal annealing (increasing from 0.8% to 1.4%) while PCPDTBT:PCBM devices have varied reactions. Furthermore, the P3HT:PCPDTBT:PCBM devices have achieved efficiencies of 1.6% in AM 1.5 compared …

Improving The Efficiency Of Organic Solar Cells By Varying The Material Concentration In The Photoactive Layer, Kevin Anthony Latimer

Electrical & Computer Engineering Theses & Dissertations

Polymer-fullerene bulk heterojunction solar cells have been a rapidly improving technology over the past decade. To further improve the relatively low energy conversion efficiencies of these solar cells, several modifications need to be made to the overall device structure. Emerging technologies include cells that are fabricated with interfacial layers to facilitate charge transport, and tandem structures are being introduced to harness the absorption spectrum of polymers with varying bandgap energies.

When new structures are implemented, each layer of the cell must be optimized in order for the entire device to function efficiently. The most volatile layer of these devices is …

Android Application Controlled Surge Protector, Lok An

Electrical Engineering

A significant amount of consumer electronics cannot be switched off completely without being unplugged. Standby power, also known as phantom power, refers to the electric power consumed by electronic appliances when they are switched off. There are some devices that need constant power; items like alarm clocks and security systems need constant power to function correctly. Some devices, such as video game consoles and televisions, consume power without offering any features. Electricity lost from standby power has been increasing with the amount of consumer electronics increasing in households.

This project’s goal is to create a low power remote that can …

Preparation And Performance Of Carbon-Coated Si/C Composites, Li-Li Du, Quan-Chao Zhuang, Tao Wei, Yong-Li Cui, Zhi Sun, Shi-Gang Sun

Journal of Electrochemistry

Si/C composite for lithium ion batteries was obtained by pyrolyzing and ball-milling. The microstructure and component of the composite was characterized by SEM and XRD, the electrochemical performance was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and galvano static charge-discharge tests. The results illustrate that the particle of Si/C composite prepared by pyrolysis exhibits inerratic morphology, uniform carbon-coating layer, good electrical conductivity, low resistance. The first intercalated-lithium capacity of the composite material is 4495 mAh/g; the first coulomb efficiency is 65.3%. From the second week the coulomb efficiency maintains 97%, and the capacity at the 100th cycle can …

Synthesis And Catalytic Property Of Flaked Spindle-Like Cuo Nanocrystals, Jian-Feng Fan, Li-Qing Li, Yu-Feng Huang, Lou-Zhen Fan

Journal of Electrochemistry

A simple and efficient electrochemical route was developed for the synthesis of flaked spindle-like CuO nanocrystals using aqueous electrolyte and Cu sacrificial anode (graphite as the cathode) in an undivided cell at a constant potential mode under room temperature. The morphologies, structure and component of CuO nanocrystals obtained were characterized by SEM, XRD, respectively. Flaked spindle-like CuO nanocrystals were successfully used to modify a GC electrode to detect H₂O₂ with cyclic voltammetry (CV) and amperometric (AC).The results showed that products were pure monoclinic CuO nanocrystals. The linear range for the determination of hydrogen peroxide is from 1.0 …

Detection Of Acute Promyelocytic Leukemia Pml/Rarî± Fusion Gene Using Graphene Modified Glassy Carbon Electrode, Zhi-Xian Lian, Guang-Xian Zhong, Kun Wang, Ai-Lin Liu, Xin-Hua Lin, Yuan-Zhong Chen

Journal of Electrochemistry

A graphene modified glassy carbon electrode (GCE) was prepared by electrochemical reduction of graphite oxide fixed on the surface of GCE. Then, the amino-group modified probe of acute promyelocytic leukemia (APL) PML/RARα fusion gene fragment was immobilized onto surface of the graphene modified GCE by coupling activating agent. With methylene blue (MB) as a novel electrochemical indicator, artificial APL PML/RARα fusion gene fragment was measured by differential pulse voltammetry (DPV). The result indicated graphene nanomaterial showed good sensitization on the signal of MB. The relationship between the reduction peak current of MB and the concentration of complementary strand was linear …

Influence Of Tert-Butylpyridine On The Band Energetics Of Nanostructured Tio2 Electrodes And The Photoelectrochemical Properties Of Dye-Seneitized Electrodes, Shu-Ming Yang, Ji-Chao Wang, Hui-Zhi Kou, Hong-Bin Xue, Hong-Jun Wang, Yu-Ling Guo

Journal of Electrochemistry

The flat band edges (Efb) of nanostructured TiO₂ electrodes in electrolyte solutions with tert-butylpyridine (TBP) of different concentrations have been determined with spectroelectrochemical technique. TBP played a role in band energetics of nanostructured TiO₂ electrodes. The Efb values of -2.25, -2.46 and -2.62 V were determined in three 0.2 mol•L^-1 tetrabutylammonium perchlorate (TBAP) acetonitrile electrolytes which contain 0, 0.2 and 0.4 mol•L^-1 TBP respectively. The addition of Li+ ions shifted Efb positively. The Efb values of -1.12, -1.22 and -1.30 V were determined in three 0.2 mol•L^-1 LiClO₄ acetonitrile electrolytes which contain 0, 0.2 …

Dft Study Of Co2 Reduction To Hydrocarbons On Cu Surfaces, Li-Hui Ou, Sheng-Li Chen

Journal of Electrochemistry

CO₂ reduction on Cu(111) single crystal surfaces was studied using DFT calculations on the reaction energies and the minimum energy paths. The results indicated that the possible reaction paths for CO₂ reduction on Cu(111) surface are CO₂(g) + H* → COOH* → (CO +OH)*, (CO + H)* → CHO*, CHO + H → CH₂O* → (CH_2⁺O)*, CH₂* + 2H* → CH₄ or 2CH₂* → C₂H₄. On Cu(111) surface, the reaction rate is controlled by steps of CH₂O* → (CH_{2 …}

Research Progress In Orthosilicates As Cathode Materials For Li-Ion Batteries, Dong-Ping Lv, Lin Wang, Yong Yang

Journal of Electrochemistry

Rechargeable Li-ion batteries fulfilling high-energy density, high safety, environmental friendliness, and low cost are demanded urgently for energy storage systems. Besides the structure stability arising from the strong Si-O covalent bond, environmental benignancy and low cost from the characteristics of Fe, Mn, Si elementals, orthosilicates (Li₂MSiO₄) show promising prospect to meet the demand of high-energy density for its two available Li+ per formula unit. Motivated by these significant advantages, Li₂MSiO₄ have been intensively investigated in the past few years. In the present work, we gave a review on the progress of orthosilicate research …

Effect Of Pore Size On Pseudo-Capacitive Performance Of Nio In The Mixed Electrolyte Of Koh And Hexacyanoferrate, Wen Wu, Meng-Yan Hou, Dan-Dan Zhou, Yong-Yao Xia

Journal of Electrochemistry

In this paper, five kinds of NiO samples with different pore size distributions were synthesized .The electrochemical capacitance of the samples were characterized in 3 mol/L KOH solution with and without hexacyanoferrate addition. Electrochemical test results indicated the NiO sample with an optimum pore size of about 15 nm shows high Coulombic efficiency of the N₄(NiO) electrode as the redox reaction of hexacyanoferrate ions would be limited in the pore, thus prevent ion diffusion into the bulk electrolyte solution .

Investigation Of Supercapacitors Based On Polyvinyl Alcohol Hydrogel-Polymer Electrolyte, Kai-Qing Xu, Le-Qing Fan, Ji-Huai Wu, Qing Leng, Xin Zhong, Jian-Ming Lin, Miao-Liang Huang, Zhang Lan

Journal of Electrochemistry

For the first time, the supercapacitor based on the hydrogel-polymer electrolyte which consisted of the cross-linking of polyvinyl alcohol-glutaraldehyde (PVA-GA) using 2-acrylamido-2-methyl propane sulfonic acid (AMPS) as solicitation reagent was assembled. The gel polymer electrolyte was characterized by FTIR and AC impedance. The maximum ionic conductivity is 1.23 mS/cm at room temperature. The electrochemical properties of the supercapacitor were investigated by cyclic voltammetry, AC impedance spectra and constant current charge-discharge curve. The results show that the specific capacitance reachs 139 F/g with AMPS of 1.0 g and 0.05 mL of 5 %(by mass) GA. And the specific capacitance still retained …

Study On Direct Electro-Oxidation Of Anisaldehyde, Lin-Lin Wu, Ying-Hong Zhu, Shan-Shan Li, Hong-Yan Zeng, Chun-An Ma

Journal of Electrochemistry

The oxidation of anisole on Pt electrode was investigated by cyclic voltammery and constant potential electrolysis. The influence of scan rates, substrate concentration, supporting electrolytes and solvent were considered . The results show that the electro-oxidation process of anisole was irreversible. In this research the sulfuric acid was the best supporting electrolytes and acetone was the best solvent, and the process was controlled by diffusion . The product of constant potential electrolysis was charactered by GC-MS .The results show that the main products was anisaldehyde, and the selectivity was up to 66.5% when using acetone as solvent.

Electric Vehicles And Power Batteries, Xin-Ping Ai, Han-Xi Yang

Journal of Electrochemistry

In retrospect of the historical development of Electric Vehicles (EV), the impact of battery technologies on the progress of EV was discussed. In consequence, it is concluded that the lack of advanced batteries was the main cause for the fluctuations of EV development and the sluggish commercialization of electric cars in the past century. After a brief introduction to the classification and the requirements of electric vehicles, the main issues of the batteries including safety, temperature range for operation and the cost as well as the effects of these factors on the applications of advanced batteries for electric vehicles were …

Comparison Of Catalytic Performance On Different Materials Supported Pd Catalysts For Formic Acid Oxidation, Su-Dong Yang, Yan-Yu Liang, Zhu-Liang Wen, Qi-Jun Song, Xiao-Gang Zhang

Journal of Electrochemistry

Graphite oxide (GO) was prepared from by Hummers method. Then the graphene nanosheets supporting Pd catalysts were prepared by a single-step chemical reduction method. The electrocatalytic performance for formic acid oxidation of the prepared Pd/graphene composite was studied as an electrode material in comparison with the composite catalysts based on the other carbons (MWCNTs, SWCNTs, and Vulcan XC-72 carbon black). X-ray diffraction (XRD) and transmission electron microscopy (TEM) measurements indicated that the Pd nanoparticles were well dispersed on the surface of the graphene nanosheets with a small particle size. The electrocatalytic oxidation of formic acid was studied by electrochemically active …

Anode Electrodeposition Of Ti/Mno2 Electrode And Electrocatalytic Oxidization Properties Of Phenol Degradation, Ye Chen, Wen-Li Zhao, Qing Wen

Journal of Electrochemistry

Ti-base manganese dioxide (Ti/MnO₂) electrode was prepared by anodically electrodeposition technology in this paper. The structure of the electrode, the microstructure of the electrode surface and the element composition of the electrode were analyzed by XRD, SEM and EDS. The preparation process parameters of the electrode were studied in detail with the help of the V~logi curve and phenol degradation curve. The Ti/MnO₂ electrode was anodically electrodeposited at current density 4mA•cm^-2, the Mn^{2 +} ions concentration 0.5mol•L^-1 and temperature70℃. The V~logi curve and phenol degradation curve were used to evaluate electrocatalytic oxidization properties …

Electrochemical Studies Of Zinc Injection Into The Structure Materials Of Nuclear Power Plants, Sheng-Han Zhang, Yu Tan, Ke-Xin Liang

Journal of Electrochemistry

The electrochemical and semiconductor characters of oxide films formed on 304L, 316L stainless steel and alloy 600 in high temperature water with zinc addition were studied. Stress corrosion cracking and occupational radiation can be retarded effectively by zinc injection to the primary circuit of pressurized water reactor (PWR). The semiconductor characters of the materials formed by zinc injection was analyzed by Mott-Schottky curves. The surface morphology and components of the corrosion oxide layer were examined and detected by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The result reveals that the smaller crystals and the complex Zn-Cr-Ni-Fe oxide were …

Electrochemical Capacitive Performance Of Mesoporous Carbon Based Co-Ni Oxides, Zhen-Sheng Yang, Ling-Bin Kong, Li Deng, Yong-Chun Luo, Long Kang

Journal of Electrochemistry

By using defects on the surface of CMK-3 served as nucleation center, Co_0.25Ni_0.75 oxide/C composite was successfully prepared through a simple chemical co-precipitation method. Characterization was carried by using X-ray diffraction, BET and scanning electron microscopy. Results showed that a perfect mesoporous network of interconnected nanoflakes was obtained for Co_0.25Ni_0.75 oxide/C composite and, this material has a less crystallization, interconnected nanoflakes network structure and a narrow mesoporous distribution at about 3~4 nm. The highly dispersed and loosely packed Co_0.25Ni_0.75 oxide/C composite possessed good electrochemical accessibility and fast diffusion rate of OH …

Correlations Of Capacitance-Voltage Hysteresis With Thin-Film Cdte Solar Cell Performance During Accelerated Lifetime Testing, David S. Albin, Joseph A. Del Cueto

Publications (E)

In this paper we present the correlation of CdTe solar cell performance with capacitance-voltage hysteresis, defined presently as the difference in capacitance measured at zero-volt bias when collecting such data with different pre-measurement bias conditions. These correlations were obtained on CdTe cells stressed under conditions of 1-sun illumination, open-circuit bias, and an acceleration temperature of approximately 100 ºC.

Use Of 2nd And 3rd Level Correlation Analysis For Studying Degradation In Polycrystalline Thin-Film Solar Cells, David S. Albin, Joseph A. Del Cueto, S. H. Demtsu, S. Bansal

Publications (E)

The correlation of stress-induced changes in the performance of laboratory-made CdTe solar cells with various 2^nd and 3^rd level metrics is discussed. The overall behavior of aggregated data showing how cell efficiency changes as a function of open-circuit voltage (V_oc), shortcircuit current density (J_sc), and fill factor (FF) is explained using a two-diode, PSpice model in which degradation is simulated by systematically changing model parameters. FF shows the highest correlation with performance during stress, and is subsequently shown to be most affected by shunt resistance, recombination and in some cases voltage-dependent collection. Large decreases …

Effect Of Hysteresis On Measurements Of Thin-Film Cell Performance, David S. Albin, Joseph A. Del Cueto

Publications (E)

Transient or hysteresis effects in polycrystalline thin film CdS/CdTe cells are a function of pre-measurement voltage bias and whether Cu is introduced as an intentional dopant during back contact fabrication. When Cu is added, the current-density (J) vs. voltage (V) measurements performed in a reverse-to-forward voltage direction will yield higher open-circuit voltage (V_oc), up to 10 mV, and smaller short-circuit current density (J_sc), by up to 2 mA/cm², relative to scanning voltage in a forward-to-reverse direction. The variation at the maximum power point, Pmax, is however small. The resulting variation in FF can be …

High Efficiency, Low Cost Solar Cells Manufactured Using ‘Silicon Ink’ On Thin Crystalline Silicon Wafers October 2009 - November 2010, Homer Antoniadis

Publications (E)

The objectives of Phase I (Feb – Oct 2009) include the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Sil-icon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to …

Hybrid Cooling Systems For Low-Temperature Geothermal Power Production, Andrea Ashwood, Desikan Bharathan

Publications (E)

The overall objective of this investigation is to identify and evaluate methods by which the net power output of an air-cooled geothermal power plant can be enhanced during hot ambient conditions using minimal amounts of water.

Geothermal power plants that use air-cooled heat rejection systems experience a decrease in power production during hot periods of the day. This decrease in power output typically coincides with the time when utilities need power to address high air conditioning loads. Hybrid cooling options, which use both air and water, have been studied for this report to assess how they might mitigate the net …

Preparation And Electrochemical Properties Of Sn Thin Film As Anode Materials For Lithium-Ion Batteries, Hong-Mei Bai, Zhan-Liang Tao, Fang-Yi Cheng, Jun Chen

Journal of Electrochemistry

Sn thin films as the anode materials of Li-ion batteries were prepared by vacuum-evaporation method on the copper foam substrate. The phase structure,surface morphology and electrochemical property of the as-prepared films were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM), and galvanostatic cycling. The results showed that three-dimensional structure of copper foam substrate enhanced the adhesion strength between the active material and the substrate, under the same substrate temperature, the particles became bigger with the increasing of evaporation time, while their electrochemical property decreased, under the same evaporation time, the particles didn′t changed obviously with the increasing of substrate temperature,while their cycle …

Electrochemical Double-Layer Capacitors Using Phenolic Resin-Based Carbon Fibers, Rong Xue, Jing-Wang Yan, Ying Tian, Bao-Lian Yi

Journal of Electrochemistry

Phenolic resin-based activated carbon fiber(ACF) was prepared by KOH activation.The electrochemical properties of pulverized phenolic resin-based carbon fiber(P-ACF) were examined in 6 mol·L^-1 KOH compared with that of the original ACF.P-ACF exhibited a better capacitive behavior and showed a larger specific capacitance(200 F·g^-1) as well as a lower capacitance decrease at high current densities.The pore resistance for ion migration(Rp) in P-ACF was lower(2.96 Ω) than that in ACF(4.65 Ω).Pulverization increased the exposure of the cross section,lowered the contact resistance between the carbon fibers and decreased the pore resistance for ion migration.

Low-Temperature Performance Of Li-Ion Battery With Fluoroethylene Carbonate Electrolyte, Chun-Wei Yang, Feng Wu, Bo-Rong Wu, Yong-Huan Ren, Jing-Wen Yao

Journal of Electrochemistry

The low temperature performance of electrolytes containing FEC including FEC+EMC, EC and PC, as well as the compatibility of electrolytes with LiFePO₄ anode and with MCMB cathode were investigated.The electrolyte exhibits a high value of ionic conductivity at low temperature.The stability of cathode was enhanced by the formation of SEI film at 1.6 V as a result of FEC reaction. The infrared spectra showed that FEC can suppress decomposition of other solvents during SEI formation, and lower the resistance of SEI on MCMB cathode. The electrochemistry test indicates that Li-ion batteries with FEC electrolyte display high capacity at low …

Synthesis Of Mesoporous Nickel Oxide For Supercapacitor Application, Xuan-Xuan Chen, Zhen-Zhen Zhao, Deng-Chao Wang, Zhong-Jie Huang, Wen-Bin Ni, Li Yu, Jian-Wei Zhao

Journal of Electrochemistry

Mesoporous nickel oxide has been synthesized by calcining metal-organic coordination precursor.Transmission electron microscopy and BET test showed that the prepared NiO had a regular morphology and displayed a narrow size distribution.Electrochemical tests revealed that such mesoporous NiO had a specific capacity of 72 F·g^-1 at the current of 2.0 A·g^-1.Futhermore,the material showed excellent cycle-life stability.There was no degradation of capacitance after 1000 cycles.