scholarly journals Electrochemical Impedance of Hydrogenated Phases of ZnO and CuO Nanoparticles for Electrode Applications

2020 ◽  
pp. 1-6
Author(s):  
L. I. Menegbo ◽  
J. L. Konne ◽  
N. Boisa
Keyword(s):  
Electrochemical Impedance ◽  
Sol Gel ◽  
Low Frequency ◽  
High Gain ◽  
High Frequency Region ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Xrd Patterns ◽  
Straight Lines ◽  
First Time

The Electrochemical Impedance Spectroscopy (EIS) measurements of Sol-gel synthesized ZnO, CuO and their respective hydrogenated phases (ZnO:H and CuO:H) for  a proton-type battery model has been reported for the first time. The XRD patterns confirmed that CuO and ZnO were phase pure with minor impurities. However, that of CuO:H showed mixed phases of CuO and Cu2O with the later  appearing prominent. The estimated particle sizes of ZnO, ZnO:H, CuO and CuO:H obtained using Scherrers’ equation were 17.83, 17.75, 21.63 and 15.42 nm respectively, showing remarkable particle size reductions upon hydrogenation as oxygen vacancies were substituted with smaller hydrogen ions. Nyquist plots from the EIS experimental data recorded over a frequency range of 100 kHz – 5 mHz showed expected flat semicircles at the high frequency region and straight lines at the low frequency regions while resistance estimations from the intercepts of the Bode plots were 12.10, 7.80, 16.00 and 10.80 Ω for ZnO, ZnO:H, CuO and CuO:H respectively. It also indicated high gain margins suggesting impressive electrochemical properties for battery applications.

Electrochemical Performance Optimization of Li2NixFe1−xSiO4 Cathode Materials for Lithium-Ion Batteries

2017 ◽  
Vol 14 (2) ◽  
Author(s):  
Atef Y. Shenouda ◽  
M. M. S. Sanad
Keyword(s):  
Performance Optimization ◽  
Electrochemical Impedance ◽  
Coulombic Efficiency ◽  
Sol Gel ◽  
Lithium Ion ◽  
Electrochemical Impedance Spectra ◽  
Cell Parameters ◽  
Sol Gel Process ◽  
Eis Measurements ◽  
And Function

Li2NixFe1−xSiO4 (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) samples were prepared by sol–gel process. The crystal structure of prepared samples of Li2NixFe1−xSiO4 was characterized by XRD. The different crystallographic parameters such as crystallite size and lattice cell parameters have been calculated. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) investigations were carried out explaining the morphology and function groups of the synthesized samples. Furthermore, electrochemical impedance spectra (EIS) measurements are applied. The obtained results indicated that the highest conductivity is achieved for Li2Ni0.4Fe0.6SiO4 electrode compound. It was observed that Li/Li2Ni0.4Fe0.6SiO4 battery has initial discharge capacity of 164 mAh g−1 at 0.1 C rate. The cycle life performance of all Li2NixFe1−xSiO4 batteries was ranged between 100 and 156 mAh g−1 with coulombic efficiency range between 70.9% and 93.9%.

scholarly journals Electrochemical Impedance Spectroscopy Evaluation of Organic Coating on Mild Steel

2018 ◽  
Vol 7 (3.11) ◽  
pp. 30
Author(s):  
Zailelah Zainoldin ◽  
Hadariah Bahron ◽  
Mohamad Kamal Harun ◽  
Syaidah Athirah Dzolin
Keyword(s):  
Mild Steel ◽  
Steel Surface ◽  
Electrochemical Impedance ◽  
Organic Coating ◽  
Electrical Equivalent Circuit ◽  
Mild Steel Surface ◽  
Electro Oxidation ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Voltammetric Technique

Electro-oxidation of 4-hydroxybenzalaniline in alkaline solution on mild steel surface was successfully carried out using cyclic voltammetric technique. Results demonstrated that brownish colour appeared on the mild steel surface after the cycle of voltammetric study. The presence of film was confirmed by the EIS measurement whereas the Nyquist plots obtained from EIS measurements were fitted with suitable electrical equivalent circuit. The coated mild steel exhibit better polarization resistance than uncoated mild steel.  

A Microfabricated Multilayer Impedance System for Ionic Transport Characterization in Nanocapillary Arrays

2006 ◽  
Author(s):  
Shaurya Prakash ◽  
Junghoon Yeom ◽  
Mark A. Shannon
Keyword(s):  
Electrochemical Impedance ◽  
Reference Electrode ◽  
Aqueous Salt Solution ◽  
Ionic Charge ◽  
Capacitive Component ◽  
Flow Through ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Rc Circuit ◽  
Rc Time Constant

A multilayer micro-electrochemical impedance spectroscopic (μ-EIS) system with an integrated Ag/AgCI reference electrode has been developed using MEMS technologies. This μ-EIS system is used to characterize ionic and fluidic transport across nanocapillary array membranes (NCAM), which are comprised of arrays of individual nanopores. Impedance measurements giving magnitude, phase, and I-V characteristics provide insight into the interaction between translocating ions and the electric double layer (EDL) within nanocapillaries due to changes in the surface zeta potential and the ionic charge of the electrolyte. μ-EIS measurements for ionic flow through the NCAM with pore diameters from 10 to 800 nm with an aqueous salt solution indicate that these NCAM behave as nearly ideal RC circuits at electrolyte concentrations on the order of 100 mM, when the EDL within these pores do not overlap. Nyquist plots show an increase in the RC time constant with decreasing salt concentration. Under conditions of EDL overlap, hindered transport in the pores causes deviation from ideal RC circuit-like behaviour with the capacitive component of impedance beginning to dominate.

scholarly journals Self-Healing Coating on Aluminium Alloy (AA2014) using a Sol - Gel Process

2021 ◽  
Vol 9 (VI) ◽  
pp. 293-300
Author(s):  
Saurabh Kumar Jha
Keyword(s):  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Ph Value ◽  
Sol Gel ◽  
Low Frequency ◽  
Barrier Properties ◽  
Immersion Test ◽  
Self Healing ◽  
High Impedance ◽  
Sol Gel Process

In this paper, a new doping concept has been improved which shows self-healing properties by sustained release of corrosion inhibitors in a carrier system. The anti-corrosive properties of (AA2014) aluminium alloy was tested by electrochemical impedance spectroscopy. The sol-gel coating doped with both inorganic and organic inhibitors gives a satisfying result. Releasing the event of inhibitor depends on the pH value of the corrosion environment. The barrier properties of the best coating divulge by high pore resistance with having high impedance value at low frequency. The immersion test confirmed that double doping concept is valuable also for long immersion test.

Electrochemical Corrosion Characterization of As-Cast Mg-7Li Alloy

2012 ◽  
Vol 557-559 ◽  
pp. 64-67
Author(s):  
Jun Gang Li ◽  
Ying Lv ◽  
Hong Wei Wang ◽  
Zhao Jun Zhu ◽  
Zun Jie Wei ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Low Frequency ◽  
Electrochemical Corrosion ◽  
Frequency Region ◽  
X Ray Diffraction ◽  
High Frequency Region ◽  
Anode Dissolution ◽  
Electrochemical Corrosion Behavior ◽  
Capacitive Reactance

The electrochemical corrosion behavior of as-cast Mg-7Li alloy in 3.5wt% NaCl aqueous solution was investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and electrochemical workstation. Results showed that the Ecorr and the Icorr of Mg-7Li alloy were -1.5857V and 2.235×10-4A/cm2, respectively. The cathode process was chiefly the hydrogen evolution reaction, and the corrosion rate of Mg-7Li alloy was mainly controlled by anode dissolution. The corrosion products on the alloy surface consisted of Mg(OH)2, Li2O2 and Al(OH)3. The electrochemical impedance spectroscopy (EIS) of Mg-7Li alloy contained two capacitive loops and one inductive loop. The inductance value increased to 250 ohm•cm-2 with a rise in frequency at low frequency region. The value of capacitive reactance decreased with increasing frequency at medium frequency. The capacitive reactance maintained the value of 50 ohm•cm-2 with increasing frequency at high frequency region.

scholarly journals Performance of corrosion protection of carbon steel with cerium modified phosphate–permanganate coatings and a layer of silane doped with cerium

Chemija ◽  
2019 ◽  
Vol 30 (3) ◽  
Author(s):  
O. Girčienė ◽  
L. Gudavičiūtė ◽  
A. Martušienė ◽  
V. Jasulaitienė ◽  
A. Selskienė ◽  
...  
Keyword(s):  
Carbon Steel ◽  
Photoelectron Spectroscopy ◽  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Low Frequency ◽  
Cerium Nitrate ◽  
Self Healing ◽  
Nacl Solution ◽  
Composition And Structure ◽  
Eis Measurements

This work was aimed to evaluate the effect of bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) doped with cerium nitrate, as a corrosion inhibitor, on improved corrosion resistance of samples of carbon steel with a phosphate–permanganate layer in a 0.5 M NaCl solution. The main goal of the present work was to compare self-healing capacities of cerium conversion coatings and cerium as an additive inhibitor to silane. The composition and structure of the investigated samples were characterized by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) techniques, while the corrosion behaviour was investigated applying voltametric and electrochemical impedance spectroscopy (EIS) measurements. The results of EIS measurements performed during 24 h immersion of the investigated samples into the 0.5 M NaCl solution revealed that the layer of silane doped with Ce was more protective than that of the non-modified one. It has been determined that the presence of cerium nitrate in the silane coating can lead to high values of low frequency impedance due to the healing of the defect.

scholarly journals Electrochemical Characterization of Az31 Magnesium Alloy Treated by Ultrasonic Impact Peening (Uip)

2018 ◽  
Vol 20 (3) ◽  
pp. 24-29
Author(s):  
Daniel Kajanek ◽  
Branislav Hadzima ◽  
Filip Pastorek
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electrochemical Impedance ◽  
Az31 Alloy ◽  
Az31 Magnesium Alloy ◽  
Electrochemical Characteristics ◽  
Nyquist Plots ◽  
Eis Measurements ◽  
Testing Solution

Electrochemical characteristics of AZ31 magnesium alloy after impacting by ultrasonic impact peening (UIP) were measured in order to evaluate its effect on corrosion resistance of mentioned alloy. For this purpose, potentio-dynamic polarization (PD) tests and electrochemical impedance spectroscopy (EIS) of ground and impacted samples were performed in 0.1 M NaCl solution at the temperature of 22±2 °C after 5 minutes of potential stabilization. The obtained PD curves were analysed using the Tafel extrapolation method and data from EIS measurements in form of Nyquist plots were quantified by the equivalent circuit method. The results showed clearly that application of the UIP significantly deteriorated corrosion resistance of AZ31 alloy in the chosen testing solution.

scholarly journals Modified Structural and Magnetic Properties of Ni-Mn-Zn Ferrite Nanoparticles Doped with Ce3+Ions

2021 ◽  
Vol 12 (4) ◽  
pp. 5021-5030
Keyword(s):  
Spinel Ferrite ◽  
Sol Gel ◽  
Lattice Parameter ◽  
Sem Analysis ◽  
Dielectric Measurements ◽  
X Ray Diffraction ◽  
High Frequency Region ◽  
X Ray ◽  
Zn Ferrite ◽  
Xrd Patterns

Polycrystalline Ni-Mn-Zn nano-ferrites doped by the fractional amount of Ce3+ ions were fabricated using the sol-gel method. Characterizations of the as-prepared samples were performed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), vibrating sample magnetometer (VSM), and dielectric measurements. Rietveld refined XRD patterns revealed the single-phase cubic spinel structure of the samples corresponds to the space group Fd-3m. Minor shifting of peak positions towards lower diffraction angles increases lattice parameter from 8.4105 to 8.4193 Å with the addition of Ce3+ ions. , The surface morphology and homogeneity of the samples were investigated by using SEM and EDAX spectra. Grain size obtained from SEM analysis is found in the range 29 nm to 33 nm with negligible agglomeration. Analysis of EDAX spectra confirms the stoichiometric proportion of the constituents. Substitution of Ce3+ ions shows typical ferromagnetic curves with enhanced saturation magnetization and magneton number from 54 to 63 emu/gm and 2.71 to 3.09 B respectively. Dielectric measurements of the entire samples show the typical behavior of spinel ferrite. The results predict that the samples are best suitable for high-frequency region applications.

scholarly journals Study of Cu Electrochemical Polishing Mechanism With Observation of Water Acceptor Diffusion

2021 ◽  
Vol 9 ◽  
Author(s):  
Kimoon Park ◽  
Jinhyun Lee ◽  
Youjung Kim ◽  
Sangwha Yoon ◽  
Bongyoung Yoo
Keyword(s):  
Electrochemical Impedance ◽  
Low Frequency ◽  
Electrochemical Analysis ◽  
Electrochemical Polishing ◽  
Salt Film ◽  
System A ◽  
Long Time ◽  
Cu Dissolution ◽  
First Time ◽  
Electrochemical Microscopy

The salt-film and water acceptor mechanisms were generally accepted mechanisms for Cu electrochemical polishing (ECP) theory. These mechanisms of Cu ECP are still controversial for a long time. Conventional and new electrochemical analysis methods were used to investigate the mechanisms and behaviors of Cu electrochemical polishing. Two cases of Cu dissolution, with and without polishing, were classified by results of linear scan voltammetry (LSV) and scanning electron microscopy (SEM). The electrochemical impedance spectroscopy (EIS) results showed the main difference in these two cases was in the low-frequency region. However, it was hard to distinguish between the salt-film and water acceptor mechanisms by conventional electrochemical analysis. A scanning electrochemical microscopy (SECM) system, a new electrochemical analysis method that measures the electrolysis currents of the water acceptors along with a set distance from the substrate, was used to investigate the Cu ECP mechanism. Accordingly, the diffusion of the water acceptors was successfully confirmed for the first time. Finally, the mechanisms of the Cu ECP are definitively described by using all analysis results.

Dielectric Properties of Sol-Gel Prepared Ni-Doped CaCu3Ti4O12 Ceramics

2012 ◽  
Vol 204-208 ◽  
pp. 4193-4196
Author(s):  
Lei Jiao ◽  
Hui Li ◽  
Yan Wei Yang ◽  
Tian Ping Wang
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Low Frequency ◽  
Frequency Region ◽  
Dielectric Constants ◽  
High Frequency Region ◽  
Xrd Pattern ◽  
Calcium Copper Titanate ◽  
Titanate Ceramics

Dielectric properties of sol–gel prepared Ni-doped calcium copper titanate Ceramics (CCNTO) are investigated. For the x of CaCu3NixTi4O12+x is 0, 0.1, 0.2, 0.3 respectively. The XRD pattern shows that crystal structure of the sample without Ni is basically single-phase. The dielectric properties of CCNTO were analyzed by Agilent 4294A. The experimental results show that the sample has a better dielectric properties when x=0.2. The maximum dielectric constants is found when x=0.2. The dielectric loss decreased with the increases of Ni in the low frequency region, the high frequency region is just the opposite, the sample has lower dielectric loss in the low frequency region when x=0.2.

Sign in / Sign up

Export Citation Format

Share Document