Impedance Spectra of a Mineral Galena Electrode: Relationship to Xanthate Flotation

1987 ◽  
Vol 134 (5) ◽  
pp. 1128-1132 ◽  
Author(s):  
D. Schuhmann ◽  
A. M. Guinard‐Baticle ◽  
P. Vanel ◽  
A. Talib
Keyword(s):  
Impedance Spectra ◽  
Galena Electrode

Performance of Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag Composite Cathode Materials for IT-SOFCs

2011 ◽  
Vol 311-313 ◽  
pp. 2309-2314 ◽  
Author(s):  
Wen Xia Zhu ◽  
Zhe Lü ◽  
Le Xin Wang ◽  
Xiao Yan Guan ◽  
Xin Yan Zhang
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Electrochemical Impedance ◽  
Composite Cathode ◽  
Solid Oxide ◽  
Electrode Polarization ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Composite Cathodes ◽  
Reduced Temperature ◽  
Resistance Value

°Abstract. In order to develop new cathodes for reduced temperature SOFCs, Ba0.5Sr0.5Co0.8Fe0.2O3-δ-Ag composite cathode was investigated in intermediate-temperature Solid Oxide Fuel Cells (IT-SOFCs). The XRD results suggested that no chemical reactions between BSCF and Ag in the composite cathode were found. The resistance measurements showed that the addition of Ag into BSCF improved electrical conductivity of pure BSCF, and the improved conductivity resulted in attractive cathode performance. In addition, electrochemical impedance spectra exhibited the better performance of BSCF-Ag composite cathodes than pure BSCF, e.g., the polarization resistance value of BSCF-Ag was only 0.36Ω cm2 at 650°C, which was nearly 80% lower than that of BSCF electrode. Polarization curves showed the overpotential decreased with the addition of Ag. The current density value of BSCF-Ag was 0.88Acm-2 under –120mV, about five times of that BSCF measured at 650°C. As a summary, compared to a pure BSCF cathode, it was found that adding Ag in the cathode enhanced the BSCF performance significantly.

scholarly journals Hysteresis Analysis of Hole-Transport-Material-Free Monolithic Perovskite Solar Cells with Carbon Counter Electrode by Current Density–Voltage and Impedance Spectra Measurements

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 48
Author(s):  
Syed Afaq Ali Shah ◽  
Muhammad Hassan Sayyad ◽  
Jinghua Sun ◽  
Zhongyi Guo
Keyword(s):  
Time Delay ◽  
Current Density ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Hole Transport ◽  
Impedance Spectra ◽  
Voltage Measurement ◽  
Sweep Time ◽  
Measurement Protocol ◽  
A Current

Due to the tremendous increase in power conversion efficiency (PCE) of organic–inorganic perovskite solar cells (PSCs), this technology has attracted much attention. Despite being the fastest-growing photovoltaic technology to date, bottlenecks such as current density–voltage (J–V) hysteresis have significantly limited further development. Current density measurements performed with different sweep scan speeds exhibit hysteresis and the photovoltaic parameters extracted from the current density–voltage measurements for both scan directions become questionable. A current density–voltage measurement protocol needs to be established which can be used to achieve reproducible results and to compare devices made in different laboratories. In this work, we report a hysteresis analysis of a hole-transport-material-free (HTM-free) carbon-counter-electrode-based PSC conducted by current density–voltage and impedance spectra measurements. The effect of sweep scan direction and time delay was examined on the J–V characteristics of the device. The hysteresis was observed to be strongly sweep scan direction and time delay dependent and decreased as the delay increased. The J–V analysis conducted in the reverse sweep scan direction at a lower sweep time delay of 0.2 s revealed very large increases in the short circuit current density and the power conversion efficiency of 57.7% and 56.1%, respectively, compared with the values obtained during the forward scan under the same conditions. Impedance spectroscopy (IS) investigations were carried out and the effects of sweep scan speed, time delay, and frequency were analyzed. The hysteresis was observed to be strongly sweep scan direction, sweep time delay, and frequency dependent. The correlation between J–V and IS data is provided. The wealth of photovoltaic and impendence spectroscopic data reported in this work on the hysteresis study of the HTM-free PSC may help in establishing a current density–voltage measurement protocol, identifying components and interfaces causing the hysteresis, and modeling of PSCs, eventually benefiting device performance and long-term stability.

Deep Neural Network Battery Impedance Spectra Prediction by Only Using Constant-Current Curve

2021 ◽  
Author(s):  
Yanzou Duan ◽  
Jinpeng Tian ◽  
Jiahuan Lu ◽  
Chenxu Wang ◽  
Weixiang Shen ◽  
...  
Keyword(s):  
Neural Network ◽  
Deep Neural Network ◽  
Constant Current ◽  
Impedance Spectra ◽  
Current Curve

Impedance eduction for uniform and multizone acoustic liners

2021 ◽  
pp. 1475472X2110238
Author(s):  
Michael G Jones ◽  
Douglas M Nark ◽  
Brian M Howerton
Keyword(s):  
Impedance Spectra ◽  
International Forum ◽  
Acoustic Liners ◽  
Prony Method ◽  
Research Challenges ◽  
Test Conditions ◽  
Acoustic Liner ◽  
Flow Impedance ◽  
Grazing Flow ◽  
Computationally Expensive

This paper presents results for five uniform and two multizone liners based on data acquired in the NASA Langley Grazing Flow Impedance Tube. Two methods, Prony and CHE, are used to educe the impedance spectra for each of these liners for many test conditions. The Prony method is efficient and generally provides accurate results for uniform liners, but is not well suited for multizone liners. The CHE method supports assessment of both uniform and multizone liners, but is much more computationally expensive. The results from these liners demonstrate the efficacy of both eduction methods, but also clearly demonstrate that sufficient attenuation is required to support accurate impedance eduction. For the liners considered in this study, the data indicate approximately 3 dB attenuation is needed for each zone of a multizone liner in order to ensure quality impedance eduction results. This study was conducted in response to two acoustic liner research challenges in support of a collaboration of multiple national laboratories under the International Forum for Aviation Research.

Impedance Analysis of Layer Structured NBT–CBT Mixed Ceramics

1998 ◽  
Vol 12 (11) ◽  
pp. 433-441 ◽  
Author(s):  
P. S. Rama Sastry ◽  
T. Bhimasankaram ◽  
G. S. Kumar ◽  
G. Prasad
Keyword(s):  
Comparative Study ◽  
Complex Impedance ◽  
Impedance Analysis ◽  
Equivalent Circuits ◽  
Impedance Spectra ◽  
Ceramic System ◽  
Different Temperatures ◽  
Mixed Ceramics ◽  
Mixed Ceramic ◽  
Complex Impedance Spectra

Complex impedance spectra of ferroelectric mixed ceramic system ( Na 0.5 Bi 0.5)1-x Ca x Bi 4 Ti 4 O 15 with x=0, 0.1, 0.3, 0.5, 0.7 and 1 was studied as a function of frequency and temperature in the range 1 KHz to 10 MHz and 30°C to 620°C respectively. Equivalent circuits involving resistive and capacitive elements at different temperatures, activation energies of relaxations and conduction were evaluated using impedance plots. A comparative study of impedance and conductivity facilities an insight in understanding the electrical nature of these electroceramics.

Investigating the dielectric properties and low-frequency relaxation process of TlGaSe2 crystals

2017 ◽  
Vol 31 (12) ◽  
pp. 1750134 ◽  
Author(s):  
Oktay Samadov ◽  
Oktay Alakbarov ◽  
Arzu Najafov ◽  
Samir Samadov ◽  
Nizami Mehdiyev ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Time ◽  
Constant Electric Field ◽  
Low Frequency ◽  
Constant Field ◽  
Impedance Spectra ◽  
Ionic Contribution ◽  
Frequency Relaxation ◽  
Average Relaxation Time ◽  
Diagram Analysis

The dielectric and impedance spectra of TlGaSe2 crystals have been studied at temperatures in the 100–500 K range in the alternating current (AC [Formula: see text]1 V). It has been shown that the conductivity of TlGaSe2 crystals is mainly an ionic characteristic at temperatures above 400 K. The well-defined peak at the frequency dependence of the imaginary part of impedance [Formula: see text] is observed in the 215–500 K temperature range. In a constant field, there occurs a significant decrease in electrical conductivity [Formula: see text] in due course. The ionic contribution to conductivity (76% at [Formula: see text]) has been estimated from a kinetic change in electrical conductivity [Formula: see text] under the influence of a constant electric field. The diagram analysis in a complex plane [Formula: see text] has been conducted by applying the method of an equivalent circuit of the substation. It has been determined that the average relaxation time of the electric module of the sample is [Formula: see text].

Interaction between Sodium Molybdate and FSWed Wled of 5083 Effected by Time

2013 ◽  
Vol 699 ◽  
pp. 645-649
Author(s):  
Chang Bin Shen
Keyword(s):  
Inhibition Efficiency ◽  
Electrochemical Impedance ◽  
Electrochemical Corrosion ◽  
Sodium Molybdate ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra ◽  
Friction Stir ◽  
Base Materials ◽  
Corrosion Behaviors ◽  
5083 Aluminum Alloy

Similar welds composed of 5083 were produced by friction stir welding. In the solution of 0.2 M NaHSO3 and 0.6 M NaCl, with the addition of a given concentration sodium molybdate as the inhibitor, the electrochemical corrosion behaviors of the friction stir welds (FSW) and 5083 were comparatively investigated by potentiodynamic polarization curve tests and electrochemical impedance spectra (EIS) at the ambient temperature for different test periods. The results indicated that : with the extension of period, the inhibition efficiencies (IE) for both the weld and 5083 base materials enhanced, at the same period, the inhibition efficiency (IE) for the weld was beyond that for 5083 base materials, sodium molybdate may be thought of as an effective inhibitor for 5083 aluminum alloy, the interaction between inhibitor and weld is stronger than that between inhibitor and base materials.

An analysis of drifts and nonlinearities in electrochemical impedance spectra

2011 ◽  
Vol 56 (22) ◽  
pp. 7467-7475 ◽  
Author(s):  
Niket S. Kaisare ◽  
Vimala Ramani ◽  
Karthik Pushpavanam ◽  
S. Ramanathan
Keyword(s):  
Electrochemical Impedance ◽  
Impedance Spectra ◽  
Electrochemical Impedance Spectra
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