Ultrafine Mn3O4 nanowires synthesized by colloidal method as electrode materials for supercapacitors with a wide voltage range

2021 ◽  
Vol 44 ◽  
pp. 103260
Author(s):  
Qisheng Fang ◽  
Mengxuan Sun ◽  
Xiaohe Ren ◽  
Baobao Cao ◽  
Wenzhong Shen ◽  
...  
Keyword(s):  
Electrode Materials ◽  
Voltage Range ◽  
Colloidal Method

Study of Alkane Thiols as a Blocking Mechanism for Specific Adsorption for Application of Charge Selective Membrane Transport

2011 ◽  
Author(s):  
Damena D. Agonafer ◽  
Edward Chainani ◽  
Muhammed E. Oruc ◽  
Ki Sung Lee ◽  
Mark A. Shannon
Keyword(s):  
Energy Cost ◽  
Electrode Materials ◽  
Electrochemical Impedance ◽  
Membrane Surface ◽  
Electrochemical Process ◽  
Layer Potential ◽  
Redox Species ◽  
Voltage Range ◽  
Track Etched Membrane ◽  
Etched Membrane

Electrodialysis (ED) is an electrochemical process used for separation of ions across perm-selective membranes. ED uses a DC bias to selectively transport ions across membranes for applications ranging from desalination of water to demineralization of fruit juice. The energy cost of ED is due to accumulation of hydroxide and hydronium ions from the electrochemical process of water; additionally there is the cost of using platinum electrodes. This paper addresses the idea of using polycarbonate track etched membrane (PCTE) coated with gold between the membranes to reduce the energy cost and to explore a wider selection of electrode materials. This paper aims to show how thiol monolayers on gold can be used as ideal polarizable electrodes (electrode behaves like a capacitor with only charging current and no faradaic current) for application of potential to the membrane surface double layer. We report the characterization of such monolayers on gold-coated microscope slides. The goal is to control the diffuse layer potential at each membrane-solution interface while at the same time prevent adsorption on the electrode surface and minimize Faradaic activity due to electrolyte and redox species in solution. This lays the groundwork for the application of thiol-modified polycarbonate track-etched membranes for ion-selective transport. The paper proposes the use of electrochemical impedance spectroscopy (EIS) to measure characteristics of gold (Au)-coated membranes and their inherent limitations. In this work, the fabrication of a membrane permeate flow cell is described with the aim of subsequently studying the transport of ions through conductive polycarbonate track etched membrane (PCTE) by interrogating the system using EIS and CV measurements. In particular, we would like to ascertain the voltage range that can be applied to the Au-coated membrane without getting a considerable faradaic activity; the difference between platinum and Au electrode; the effects of different electrolyte concentrations and various applied DC potentials.

scholarly journals Effect of FSI Based Ionic Liquid on High Voltage Li-Ion Batteries

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2879
Author(s):  
Wenlin Zhang ◽  
Yongqi Zhao ◽  
Yu Huo
Keyword(s):  
Ionic Liquid ◽  
Molecular Orbital ◽  
High Voltage ◽  
Electrode Materials ◽  
Ethylene Carbonate ◽  
Solid Electrolyte Interphase ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Voltage Range ◽  
Discharge Specific Capacity

In this manuscript, a functionalized ionic liquid 1-cyanoethyl-2-methyl-3-allylimidazolium bis (trifluoromethanesulfonimide) salt (CEMAImTFSI) was synthesized and explored as an electrolyte component to improve the oxidation resistance of the electrolyte in high-voltage lithium-ion batteries. Based on the calculation by Gaussian 09, CEMAImTFSI has a higher highest occupied molecular orbital (HOMO) value than the organic solvents ethylene carbonate (EC) and dimethyl carbonate (DMC), suggesting that CEMAImTFSI is more susceptible to oxidation than EC and DMC. Moreover, a low Li+ binding energy value of –3.71 eV and the lower lowest unoccupied molecular orbital (LUMO) enable CEMAImTFSI to migrate easily to the surface of the LiNi0.5Mn1.5O4 cathode and participate in the formation of the SEI (solid electrolyte interphase) film, protecting the electrode materials. Electrochemical studies showed that the LiNi0.5Mn1.5O4/Li cell with 1.0 mol/L LiPF6-EC/DMC/10 vol% has the best cycling stability in the voltage range of 3–5 V. The initial discharge specific capacity of the cells was 131.03 mAh·g−1 at 0.2 C, and even after 50 cycles the discharge specific capacity value of 126.06 mAhg−1 was observed, with the cell showing a capacity retention as high as 96.2%. Even at the rate of 5 C, the average discharge specific capacity of the cell was still 109.30 mAh·g−1, which was 1.95 times higher than the cell without the CEMAImTFSI addition. The ionic liquid molecules adsorption on the cell electrode surface was confirmed by X-ray photoelectron spectroscopic (XPS) analysis after charge–discharge measurements.

scholarly journals Designing a hybrid electrode toward high energy density with a staged Li+ and PF6− deintercalation/intercalation mechanism

2020 ◽  
Vol 117 (6) ◽  
pp. 2815-2823 ◽  
Author(s):  
Junnan Hao ◽  
Fuhua Yang ◽  
Shilin Zhang ◽  
Hanna He ◽  
Guanglin Xia ◽  
...  
Keyword(s):  
Energy Density ◽  
Structural Integrity ◽  
Electrode Materials ◽  
High Capacity ◽  
Lithium Ion ◽  
High Energy ◽  
High Energy Density ◽  
Ex Situ ◽  
Discharge Process ◽  
Voltage Range

Existing lithium-ion battery technology is struggling to meet our increasing requirements for high energy density, long lifetime, and low-cost energy storage. Here, a hybrid electrode design is developed by a straightforward reengineering of commercial electrode materials, which has revolutionized the “rocking chair” mechanism by unlocking the role of anions in the electrolyte. Our proof-of-concept hybrid LiFePO4 (LFP)/graphite electrode works with a staged deintercalation/intercalation mechanism of Li+ cations and PF6− anions in a broadened voltage range, which was thoroughly studied by ex situ X-ray diffraction, ex situ Raman spectroscopy, and operando neutron powder diffraction. Introducing graphite into the hybrid electrode accelerates its conductivity, facilitating the rapid extraction/insertion of Li+ from/into the LFP phase in 2.5 to 4.0 V. This charge/discharge process, in turn, triggers the in situ formation of the cathode/electrolyte interphase (CEI) layer, reinforcing the structural integrity of the whole electrode at high voltage. Consequently, this hybrid LFP/graphite-20% electrode displays a high capacity and long-term cycling stability over 3,500 cycles at 10 C, superior to LFP and graphite cathodes. Importantly, the broadened voltage range and high capacity of the hybrid electrode enhance its energy density, which is leveraged further in a full-cell configuration.

Coprinus Comatus-Based Nitrogen-Doped Active Carbon for High Performance Supercapacitor

NANO ◽  
2017 ◽  
Vol 12 (08) ◽  
pp. 1750103 ◽  
Author(s):  
Guofu Ma ◽  
Wei Tang ◽  
Kanjun Sun ◽  
Zhiguo Zhang ◽  
Enke Feng ◽  
...  
Keyword(s):  
Specific Capacitance ◽  
Current Density ◽  
High Performance ◽  
Electrode Materials ◽  
High Current Density ◽  
Chemical Activation ◽  
Voltage Range ◽  
Coprinus Comatus ◽  
Nitrogen Doped ◽  
Symmetric Supercapacitor

Coprinus comatus-based nitrogen-doped activated carbon (N-ACC) is prepared by chemical activation and nitrogen-doped methods. The N-ACC possesses large specific surface areas (976.96[Formula: see text]m2[Formula: see text]g[Formula: see text]), high nitrogen contents (11.53[Formula: see text]wt.%), and super hydrophilicity. As electrode material for supercapacitors, the N-ACC shows remarkable electrochemical performance, such as 346[Formula: see text]F[Formula: see text]g[Formula: see text] maximum specific capacitance at a current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text], which retains 260[Formula: see text]F[Formula: see text]g[Formula: see text] even at a high current density of 10[Formula: see text]A[Formula: see text]g[Formula: see text] (about 75% capacitance retention) in 2[Formula: see text]M KOH aqueous electrolyte. The assembled N-ACC//N-ACC symmetric supercapacitor exhibits energy density of 14.63[Formula: see text]Wh[Formula: see text]kg[Formula: see text] at power density of 810[Formula: see text]W kg[Formula: see text], and excellent cycling stability with 92% specific capacitance retention after 10000 cycles in the voltage range 0–1.8[Formula: see text]V in 0.5[Formula: see text]M Na2SO4 aqueous solution. These results indicate that the N-ACC as electrode materials can be used for high performance supercapacitors.

scholarly journals Towards Reversible High-Voltage Multi-Electron Reactions in Alkali-Ion Batteries Using Vanadium Phosphate Positive Electrode Materials

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1428
Author(s):  
Edouard Boivin ◽  
Jean-Noël Chotard ◽  
Christian Masquelier ◽  
Laurence Croguennec
Keyword(s):  
High Voltage ◽  
Electrode Materials ◽  
Positive Electrode ◽  
Vanadium Phosphate ◽  
Voltage Range ◽  
Redox Couples ◽  
Vanadium Phosphates ◽  
Vanadium Redox ◽  
Alkali Ion ◽  
Positive Electrode Materials

Vanadium phosphate positive electrode materials attract great interest in the field of Alkali-ion (Li, Na and K-ion) batteries due to their ability to store several electrons per transition metal. These multi-electron reactions (from V2+ to V5+) combined with the high voltage of corresponding redox couples (e.g., 4.0 V vs. for V3+/V4+ in Na3V2(PO4)2F3) could allow the achievement the 1 kWh/kg milestone at the positive electrode level in Alkali-ion batteries. However, a massive divergence in the voltage reported for the V3+/V4+ and V4+/V5+ redox couples as a function of crystal structure is noticed. Moreover, vanadium phosphates that operate at high V3+/V4+ voltages are usually unable to reversibly exchange several electrons in a narrow enough voltage range. Here, through the review of redox mechanisms and structural evolutions upon electrochemical operation of selected widely studied materials, we identify the crystallographic origin of this trend: the distribution of PO4 groups around vanadium octahedra, that allows or prevents the formation of the vanadyl distortion (O…V4+=O or O…V5+=O). While the vanadyl entity massively lowers the voltage of the V3+/V4+ and V4+/V5+ couples, it considerably improves the reversibility of these redox reactions. Therefore, anionic substitutions, mainly O2− by F−, have been identified as a strategy allowing for combining the beneficial effect of the vanadyl distortion on the reversibility with the high voltage of vanadium redox couples in fluorine rich environments.

Analysis of photographic emulsions for High-Voltage Electron Microscopy

1993 ◽  
Vol 51 ◽  
pp. 452-453 ◽  
Author(s):  
James R. Kremer ◽  
Paul S. Furcinitti ◽  
Eileen O’Toole ◽  
J. Richard McIntosh
Keyword(s):  
Electron Microscope ◽  
Optical Density ◽  
High Voltage ◽  
Noise Power ◽  
Limited Information ◽  
Modulation Transfer ◽  
Transmission Microscopy ◽  
High Voltage Electron Microscopy ◽  
Voltage Range ◽  
Voltage Electron

Characteristics of electron microscope film emulsions, such as the speed, the modulation transfer function, and the exposure dependence of the noise power spectrum, have been studied for electron energies (80-100keV) used in conventional transmission microscopy. However, limited information is available for electron energies in the intermediate to high voltage range, 300-1000keV. Furthermore, emulsion characteristics, such as optical density versus exposure, for new or improved emulsions are usually only quoted by film manufacturers for 80keV electrons. The need for further film emulsion studies at higher voltages becomes apparent when searching for a film to record low dose images of radiation sensitive biological specimens in the frozen hydrated state. Here, we report the optical density, speed and relative resolution of a few of the more popular electron microscope films after exposure to 1MeV electrons.Three electron microscope films, Kodak S0-163, Kodak 4489, and Agfa Scientia 23D56 were tested with a JEOLJEM-1000 electron microscope operating at an accelerating voltage of 1000keV.

A novel ligand with –NH2 and –COOH-decorated Co/Fe-based oxide for an efficient overall water splitting: dual modulation roles of active sites and local electronic structure

2020 ◽  
Vol 10 (18) ◽  
pp. 6266-6273
Author(s):  
Yalan Zhang ◽  
Zebin Yu ◽  
Ronghua Jiang ◽  
Jung Huang ◽  
Yanping Hou ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Water Splitting ◽  
Energy Demand ◽  
Active Sites ◽  
Electrode Materials ◽  
Global Energy ◽  
Overall Water Splitting ◽  
Local Electronic Structure ◽  
Electrochemical Water Splitting

Excellent electrochemical water splitting with remarkable durability can provide a solution to satisfy the increasing global energy demand in which the electrode materials play an important role.

High-voltage monitoring by the fiber-optic recirculating measuring system

2020 ◽  
pp. 38-44
Author(s):  
A. V. Polyakov ◽  
M. A. Ksenofontov
Keyword(s):  
Optical Fibers ◽  
High Voltage ◽  
Optical Sensors ◽  
Electromagnetic Interference ◽  
Fiber Optic ◽  
Electric Power Industry ◽  
Measuring System ◽  
Voltage Range ◽  
External Electromagnetic Fields ◽  
Optic Communication

Optical technologies for measuring electrical quantities attract great attention due to their unique properties and significant advantages over other technologies used in high-voltage electric power industry: the use of optical fibers ensures high stability of measuring equipment to electromagnetic interference and galvanic isolation of high-voltage sensors; external electromagnetic fields do not influence the data transmitted from optical sensors via fiber-optic communication lines; problems associated with ground loops are eliminated, there are no side electromagnetic radiation and crosstalk between the channels. The structure and operation principle of a quasi-distributed fiber-optic high-voltage monitoring system is presented. The sensitive element is a combination of a piezo-ceramic tube with an optical fiber wound around it. The device uses reverse transverse piezoelectric effect. The measurement principle is based on recording the change in the recirculation frequency under the applied voltage influence. When the measuring sections are arranged in ascending order of the measured effective voltages relative to the receiving-transmitting unit, a relative resolution of 0,3–0,45 % is achieved for the PZT-5H and 0,8–1,2 % for the PZT-4 in the voltage range 20–150 kV.

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