Corrosion Behavior of Zinc Covered with Native Oxides Under Thin Solution Films

CORROSION ◽  
10.5006/3523 ◽  
2020 ◽  
Vol 76 (6) ◽  
pp. 562-569
Author(s):  
Chulaluk Somphotch ◽  
Azusa Ooi ◽  
Eiji Tada ◽  
Atsushi Nishikata
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Atmospheric Corrosion ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Native Oxide ◽  
Transfer Resistance ◽  
Native Oxides ◽  
Different Temperatures ◽  
Humidified Air

This study clarified the influence of native oxides on the atmospheric corrosion of Zn. The electrochemical impedance spectroscopy (EIS) values of native-oxide-covered Zn were measured under thin solution films of 10 μm to 500 μm in thickness. The native oxides were formed by exposing pure Zn plates to humidified air at two different temperatures, 25°C and 60°C, for the duration of one week. EIS was applied to the native-oxide-covered Zn for measurement under thin solution films; the results were analyzed using a transmission line equivalent circuit to determine the charge-transfer resistance (Rct). The native oxide formed at 25°C strongly suppressed the corrosion rate (1/Rct) of Zn, which was independent of the solution film thickness (Xf). However, the 1/Rct was not reduced by the native oxides formed at 60°C, as it was dependent on Xf. This paper discusses the different behaviors of the native oxides in the context of corrosion protection.

scholarly journals Electrochemical Impedance Spectroscopy on the Performance Degradation of LiFePO4/Graphite Lithium-Ion Battery Due to Charge-Discharge Cycling under Different C-Rates

Energies ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 4507 ◽  
Author(s):  
Yusuke Abe ◽  
Natsuki Hori ◽  
Seiji Kumagai
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Specific Capacity ◽  
Lithium Ion ◽  
Performance Degradation ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Charge Discharge

Lithium-ion batteries (LIBs) using a LiFePO4 cathode and graphite anode were assembled in coin cell form and subjected to 1000 charge-discharge cycles at 1, 2, and 5 C at 25 °C. The performance degradation of the LIB cells under different C-rates was analyzed by electrochemical impedance spectroscopy (EIS) and scanning electron microscopy. The most severe degradation occurred at 2 C while degradation was mitigated at the highest C-rate of 5 C. EIS data of the equivalent circuit model provided information on the changes in the internal resistance. The charge-transfer resistance within all the cells increased after the cycle test, with the cell cycled at 2 C presenting the greatest increment in the charge-transfer resistance. Agglomerates were observed on the graphite anodes of the cells cycled at 2 and 5 C; these were more abundantly produced in the former cell. The lower degradation of the cell cycled at 5 C was attributed to the lowered capacity utilization of the anode. The larger cell voltage drop caused by the increased C-rate reduced the electrode potential variation allocated to the net electrochemical reactions, contributing to the charge-discharge specific capacity of the cells.

Thermal transitions in hydrated layer-by-layer assemblies observed using electrochemical impedance spectroscopy

Soft Matter ◽  
2014 ◽  
Vol 10 (34) ◽  
pp. 6467-6476 ◽  
Author(s):  
Choonghyun Sung ◽  
Katelin Hearn ◽  
Jodie Lutkenhaus
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Thermal Transition ◽  
Layer By Layer ◽  
Thermal Transitions ◽  
Transfer Resistance ◽  
Hydrated Layer

Layer-by-layer assemblies exhibit increased conductivity and decreased charge transfer resistance upon heating through the thermal transition.

scholarly journals An Investigation on Dislocation Density in Cold-Rolled Copper Using Electrochemical Impedance Spectroscopy

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Elyas Rafiee ◽  
Mansour Farzam ◽  
Mohammad Ali Golozar ◽  
Ali Ashrafi
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Dislocation Density ◽  
Electrochemical Impedance ◽  
Pure Copper ◽  
Annealed Sample ◽  
Charge Transfer Resistance ◽  
Transfer Resistance ◽  
Cold Rolled

Variation of electrochemical impedance with dislocation density was investigated using electrochemical impedance spectroscopy (EIS). For this purpose, EIS measurements were carried out on 10, 20, 30, 40, and 50% cold-rolled commercially pure copper in 0.1 M NaCl (pH = 2) solution. Nyquist plots illustrated that the electrochemical reactions are controlled by both charge transfer and diffusion process. Increasing dislocation density, the magnitude of electrochemical impedance of samples was decreased. Decreasing magnitude of impedance at intermediate frequencies indicated increasing double-layer capacitance. Charge transfer resistance decreased from value 329.6 Ωcm2 for annealed sample to 186.3 Ωcm2 for sample with maximum dislocation density (1.72×1015 m−2). Phase angles were lower for samples that contained more dislocation density, indicating more tendencies to loss of electrons and releasing atoms into electrolyte.

scholarly journals Deciphering the Disaggregation Mechanism of Amyloid Beta Aggregate by 4-(2-Hydroxyethyl)-1-Piperazinepropanesulfonic Acid Using Electrochemical Impedance Spectroscopy

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 788
Author(s):  
Hien T. Ngoc Le ◽  
Sungbo Cho
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Amyloid Β ◽  
Electrochemical Measurement ◽  
Charge Transfer Resistance ◽  
Chemical Agent ◽  
Transfer Resistance ◽  
K Value

Aggregation of amyloid-β (aβ) peptides into toxic oligomers, fibrils, and plaques is central in the molecular pathogenesis of Alzheimer’s disease (AD) and is the primary focus of AD diagnostics. Disaggregation or elimination of toxic aβ aggregates in patients is important for delaying the progression of neurodegenerative disorders in AD. Recently, 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid (EPPS) was introduced as a chemical agent that binds with toxic aβ aggregates and transforms them into monomers to reduce the negative effects of aβ aggregates in the brain. However, the mechanism of aβ disaggregation by EPPS has not yet been completely clarified. In this study, an electrochemical impedimetric immunosensor for aβ diagnostics was developed by immobilizing a specific anti-amyloid-β (aβ) antibody onto a self-assembled monolayer functionalized with a new interdigitated chain-shaped electrode (anti-aβ/SAM/ICE). To investigate the ability of EPPS in recognizing AD by extricating aβ aggregation, commercially available aβ aggregates (aβagg) were used. Electrochemical impedance spectroscopy was used to probe the changes in charge transfer resistance (Rct) of the immunosensor after the specific binding of biosensor with aβagg. The subsequent incubation of the aβagg complex with a specific concentration of EPPS at different time intervals divulged AD progression. The decline in the Rct of the immunosensor started at 10 min of EPPS incubation and continued to decrease gradually from 20 min, indicating that the accumulation of aβagg on the surface of the anti-aβ/SAM/ICE sensor has been extricated. Here, the kinetic disaggregation rate k value of aβagg was found to be 0.038. This innovative study using electrochemical measurement to investigate the mechanism of aβagg disaggregation by EPPS could provide a new perspective in monitoring the disaggregation periods of aβagg from oligomeric to monomeric form, and then support for the prediction and handling AD symptoms at different stages after treatment by a drug, EPPS.

scholarly journals Investigation of Temperature and Aging Effects in Nanostructured Dye Solar Cells Studied by Electrochemical Impedance Spectroscopy

2009 ◽  
Vol 2009 ◽  
pp. 1-15 ◽  
Author(s):  
Minna Toivola ◽  
Janne Halme ◽  
Lauri Peltokorpi ◽  
Peter Lund
Keyword(s):  
Solar Cells ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Aging Effects ◽  
Transfer Resistance ◽  
Deterioration Rate ◽  
Dye Solar Cells ◽  
Effects Of Aging

Effects of aging and cyclically varying temperature on the electrical parameters of dye solar cells were analyzed with electrochemical impedance spectroscopy. Photoelectrode total resistance increased as a function of time due to increasing electron transport resistance in theTiO2film. On the other hand, photoelectrode recombination resistance was generally larger, electron lifetimes in theTiO2were film longer, and charge transfer resistance on the counter electrode was smaller after the temperature treatments than before them. These effects correlated with the slower deterioration rate of the temperature-treated cells, in comparison to the reference cells.

MONITORED DEFORMATION BY POTENTIAL-INDUCED DEFECTS IN CH3(CH2)n−1SH SELF-ASSEMBLED MONOLAYERS ON GOLD: EIS STUDY OF CHAIN LENGTH EFFECT ON SUBDIFFUSION AND SAMs’ HETEROGENEITY

2019 ◽  
Vol 26 (10) ◽  
pp. 1950067 ◽  
Author(s):  
AHMED MOUGARI ◽  
MOKHTAR ZABAT ◽  
SMAIL BOUDJADAR
Keyword(s):  
Charge Transfer ◽  
Electrochemical Impedance ◽  
Defect Density ◽  
Charge Transfer Resistance ◽  
Electrical Circuit ◽  
Transfer Resistance ◽  
Low Frequencies ◽  
Interface Evolution ◽  
Impedance Measurements ◽  
Self Assembled

From the defects-free self-assembled organic layers (SAMs) of CH3([Formula: see text]SH molecules with short chain lengths ([Formula: see text]) electrodeposited on the (111) surface of monocrystalline gold previously prepared, monitored defects (pinholes) were potential-induced from cyclic partial reduction of SAMs at an appropriate potential. Electrochemical impedance measurements were in-situ conducted and [Fe(CN)6][Formula: see text] ions were used as probes for mass and charge transfer. Interface evolution was modeled with an equivalent electrical circuit containing two distinct constant-phase elements (CPEs). One is a generalized semi-infinite Warburg element in series with a charge transfer resistance attributed to subdiffusion phenomenon through leaky sublayers at low frequencies; the other CPE is used for characterizing the interface heterogeneity at medium and high frequencies. At low frequencies, electrochemical impedance measurements show subdiffusion phenomenon, which depends on the remaining sublayer and its thickness. When the defect density increases, diffusion tends to be ordinary, obeying the Fick’s law.

scholarly journals Electrochemical behaviour of poly(3,4-ethylenedioxytiophene) modified glassy carbon electrodes after overoxidation − the influence of the substrate on the charge transfer resistance

2018 ◽  
Author(s):  
Dora Zalka ◽  
Soma Vesztergom ◽  
Mária Ujvári ◽  
Gyözö Láng
Keyword(s):  
Charge Transfer ◽  
Glassy Carbon ◽  
Electrochemical Impedance ◽  
Electrochemical Behaviour ◽  
Mechanistic Explanation ◽  
Time Instant ◽  
Charge Transfer Resistance ◽  
Polymer Chains ◽  
Transfer Resistance ◽  
Impedance Measurements

<p class="PaperAbstract">Time dependence of the electrochemical impedance of an overoxidized glassy carbon|poly(3,4-ethylenedioxytiophene) (PEDOT)|0.1 mol·dm<sup>-3</sup> sulfuric acid (aq.) elec­trode has been investigated. To follow the changes occurring at the film/substrate interface after the overoxidation procedure, successive impedance measurements were carried out. Although the system is intrinsically nonstationary, the charge transfer resis­tance (R<sub>ct</sub>) cor<strong>­</strong>res<strong>­</strong>ponding to different time instants could be determined by using the so-called 4-dimensional analysis method. The same post-experimental mathematic­cal/ana­lytical procedure could be used also for the estimation of the charge transfer resistance corresponding to the time instant just after overoxidation of the PEDOT film. The increase of the charge transfer resistance of the overoxidized system with respect to that of the pristine electrode suggests that during overoxidation the electrochemical activity of the film decreases and the charge transfer process at the metal/film interface beco­mes more hindered. After the overoxidation procedure, when the electrode potential was held in the “stability region” (at E = 0.4 V vs. SSCE in the present case) the R<sub>ct</sub> decre­ased continuously with experiment time to a value somewhat higher than that of the pristine electrode.<strong> </strong>By comparing the properties of the GC|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> and the Au|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> electrodes a possible mechanistic explanation for the observed behavior has been proposed. This is based on the assumption that in the case of the GC|PEDOT|0.1 M H<sub>2</sub>SO<sub>4</sub> electrode two processes may occur simultaneously during the impedance measurements: (a) reduction of the oxidized surface of the GC substrate, including the reduction of the oxygen-containing surface functionalities and (b) read­sorption of the polymer chains (polymer chain ends) on the surface.<strong></strong></p>

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