Combination of Electrochemical Impedance Spectroscopy and Cyclic Voltammetry to Investigate Oxygen Ion Transport in YSZ Electrolyte of SOFC

2019 ◽  
Vol 7 (1) ◽  
pp. 1293-1298
Author(s):  
Warunya Boonjob ◽  
Nitinai -. Punbusayakul ◽  
Ron -. Beckett ◽  
Manop -. Masomtub ◽  
Kitsadate -. Wongtidad ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Ion Transport ◽  
Electrochemical Impedance ◽  
Oxygen Ion ◽  
Ysz Electrolyte

Geometrical Optimization of Double Layer LSM/LSM-YSZ Cathodes by Electrochemical Impedance Spectroscopy

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
Rui Antunes ◽  
Tomasz Golec ◽  
Mirosław Miller ◽  
Ryszard Kluczowski ◽  
Mariusz Krauz ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Layer Thickness ◽  
Electrochemical Impedance ◽  
Operating Temperature ◽  
Contact Layer ◽  
Cell Performance ◽  
Functional Grade ◽  
Functional Layer ◽  
Ysz Electrolyte

The present-day high-temperature solid oxide fuel cells (SOFCs), based on yttria-stabilized zirconia (YSZ) electrolyte, a lanthanum-strontium manganite (LSM) cathode and a nickel-YSZ cermet anode, operate at 800–1000°C. Cathode materials are restricted to doped lanthanum manganites due to their stability in oxidizing atmosphere, sufficient electrical conductivity, and thermal expansion match to the YSZ electrolyte. Reduction in the operating temperature of SOFCs is desirable to lower the costs and to overcome the technological disadvantages associated with elevated temperatures. However, as the operating temperature is reduced, the decrease in the LSM conductivity and increase in interfacial polarization resistances between the LSM cathode and YSZ electrolyte become critical. Therefore, different approaches have been proposed to improve interfacial quality and electrochemical performance of the LSM/YSZ cathode. The length of the triple-phase boundary (TPB) correlates well with the interfacial resistances to electrochemical oxidation of hydrogen at the anode and reduction in oxygen at the cathode. The extension of the TPB or the number of active reaction sites becomes, therefore, a determining factor in improving electrode performance. This can be achieved by developing electrode materials of higher ambipolar conductivity and by optimizing the microstructure of the electrodes. In order to improve SOFC performance, both composition and structure of the LSM/YSZ interface and of the cathode should be optimized. Recently, functional grade materials (FGMs) were introduced for SOFC technology. However, all studies reported in the literature so far, were focused on cathodes with only compositional gradient. On the other hand, intuitionally the best structure for a functional SOFC should be characterized by both compositional and porosity gradients. Fine grains (and high surface area) close to the electrode/electrolyte surface and large grains (and thus large pore size) at the air/oxygen side are expected to be of advantage. In the present study, “symmetrical” cathode-electrolyte-cathode SOFC single cells were fabricated. The cells consisted of the functional grade LSM cathode with YSZ/LSM cathode functional layer and LSM contact layer. The effects of various geometrical and microstructural parameters of cathode/functional layers on the overall cell performance were systematically investigated. The parameters investigated were the (1) cathode functional layer thickness and grain size and (2) the LSM contact layer thickness. Cathode performances were tested by means of electrochemical impedance spectroscopy (EIS) over a temperature range of 650–950°C, using air as oxidant. The dependence of cell performance on various parameters was rationalized by a comprehensive microscale model. A cathode polarization corresponding to 0.14–0.4 Ω cm2 at 750°C was achieved in this manner.

scholarly journals Phenol Removal from Wastewaters by Electrochemical Biosensor

2019 ◽  
pp. 24-32
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Biosensor ◽  
Electrochemical Impedance ◽  
Experimental Results ◽  
Phenol Oxidation ◽  
Phenol Removal ◽  
Natural Phosphate ◽  
The Matrix

The aim of this work is to introduce bacteria into the matrix of natural phosphate to catalyze the phenol oxidation in the wastewater.This electrode, designated subsequently by bacteria-NP-CPE, Showed stable response and was characterized with voltammeter methods, as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and DRX. The experimental results revealed that the prepared electrode could be a feasible for degradation of hazardous phenol pollutants in the wastewater.

scholarly journals Chiral Discrimination of Tryptophan Enantiomers via (1R, 2R)-2-Amino-1, 2-Diphenyl Ethanol Modified Interface

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Juan Zhou ◽  
Qiao Chen ◽  
Li-lan Wang ◽  
Yong-hua Wang ◽  
Ying-zi Fu
Keyword(s):  
Cyclic Voltammetry ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Chiral Discrimination ◽  
Characteristic Analysis ◽  
Tryptophan Enantiomers ◽  
Sensitive Property ◽  
The Stability ◽  
Relative Change

The paper reported that a simple chiral selective interface constructed by (1R, 2R)-2-amino-1, 2-diphenyl ethanol had been developed to discriminate tryptophan enantiomers. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for the characteristic analysis of the electrode. The results indicated that the interface showed stable and sensitive property to determine the tryptophan enantiomers. Moreover, it exhibited the better stereoselectivity for L-tryptophan than that for D-tryptophan. The discrimination characteristics of the chiral selective interface for discriminating tryptophan enantiomers, including the response time, the effect of tryptophan enantiomers concentration, and the stability, were investigated in detail. In addition, the chiral selective interface was used to determine the enantiomeric composition of L- and D-tryptophan enantiomer mixtures by measuring the relative change of the peak current as well as in pure enantiomeric solutions. These results suggested that the chiral selective interface has the potential for enantiomeric discrimination of tryptophan enantiomers.

Sign in / Sign up

Export Citation Format

Share Document