An Electrochemical Impedance Spectroscopy (EIS) Study of Zn-Doped Li (Ni1/3Co1/3Mn1/3) O2 Cathode Materials in the First Delithiation Process

2013 ◽  
Vol 833 ◽  
pp. 50-55 ◽  
Author(s):  
Lu Zheng ◽  
Liang Bin Liu ◽  
Xiao Jing Zhou ◽  
Yu Zhong Guo
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Cathode Materials ◽  
Electrochemical Impedance ◽  
Crystalline Lattice ◽  
Zn Doping ◽  
Voltage Range ◽  
Sei Film ◽  
Zinc Doping ◽  
Co Precipitation

Li (Ni1/3Co1/3Mn1/3) O2 cathode materials doped by Zn were synthesized by a co-precipitation routine, the first delithiation process of the samples with 0-4wt% of Zn doping were studied by electrochemical impedance spectroscopy (EIS) under the polarized voltage of 2.8-4.6V. The fitting results based on EIS data indicate that delithiation reactions happen within the voltage range of 3.7-4.4V ; The resistances of SEI film and charge transfer are both decreased significantly, whereas Li+ diffusion ability through layered crystalline lattice is improved largely with the increase of zinc doping from 0 to 4wt%.

Study of Insulating Properties of Alkanethiol Self-Assembled Monolayers Formed Under Prolonged Incubation Using Electrochemical Impedance Spectroscopy

2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Damena D. Agonafer ◽  
Edward Chainani ◽  
Muhammed E. Oruc ◽  
Ki Sung Lee ◽  
Mark A. Shannon
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Critical Voltage ◽  
Transfer Resistance ◽  
Low Frequencies ◽  
Prolonged Incubation ◽  
Voltage Range ◽  
Self Assembled

The electrochemical interfacial properties of a well-ordered self-assembled monolayer (SAM) of 1-undecanethiol (UDT) on evaporated gold surface have been investigated by electrochemical impedance spectroscopy (EIS) in electrolytes without a redox couple. Using a constant-phase element (CPE) series resistance model, prolonged incubation times (up to 120 h) show decreasing monolayer capacitance approaching the theoretical value for 1-undecanethiol. Using the CPE exponent α as a measure of ideality, it was found that the monolayer approaches an ideal dielectric (α = 0.992) under prolonged incubation, which is attributed to the reduction of pinholes and defects in the monolayer during coalescence and annealing of SAM chains. The SAMs behave as insulators until a critical potential, Vc, is exceeded in both cathodic and anodic regimes, where electrolyte ions are believed to penetrate the monolayers. Using a Randles circuit model for these cases, the variation of the capacitance and charge transfer resistance with applied dc potential shows decreased permeability to ionic species with prolonged incubation time. The EIS data show that UDT (methylene chain length n = 10), incubated for 120 h, forms a monolayer whose critical voltage range extends from −0.3 to 0.5 V versus Ag/AgCl, previously attained only for alkanethiol at n = 15. At low frequencies where ion diffusion occurs, almost pure capacitive phase (−89 deg) was attained with lengthy incubation.

Analysis by electrochemical impedance spectroscopy of new MCFC cathode materials

2000 ◽  
Vol 86 (1-2) ◽  
pp. 309-315 ◽  
Author(s):  
F.J Pérez ◽  
D Duday ◽  
M.P Hierro ◽  
C Gómez ◽  
M Romero ◽  
...  
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Cathode Materials ◽  
Electrochemical Impedance

Titania Containing Cathodes for Lithium-Sulfur Batteries: Case Studies by Electrochemical Impedance Spectroscopy

2021 ◽  
Vol 105 (1) ◽  
pp. 169-176
Author(s):  
Ladislav Kavan ◽  
Monika Vinarcikova ◽  
Magda Zlámalová ◽  
Marketa Zukalova
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrolyte Solution ◽  
Cathode Materials ◽  
Redox Reactions ◽  
Electrochemical Impedance ◽  
Barrier Material ◽  
Lithium Sulfur Batteries ◽  
Commercial Carbon ◽  
Lithium Sulfur

Electrochemical impedance spectroscopy is used to study novel cathode materials for lithium-sulfur batteries, based on commercial carbon and titania. Coin cells with Li anode are investigated at various stages of galvanostatic cycling. For comparison, also symmetrical coin cells with a pair of positive (S/C/TiO2) or negative (Li) electrodes are studied. In addition to the application of titania as a barrier material impeding the polysulfide diffusion in the electrolyte solution, the inherent Li-insertion activity of TiO2 (anatase) and its contribution to the sulfur redox reactions is discussed.

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