Criteria for Reliable Electrochemical Impedance Measurements on Li-Ion Battery Anodes

2003 ◽  
Vol 150 (2) ◽  
pp. A143 ◽  
Author(s):  
Chunsheng Wang ◽  
A. John Appleby ◽  
Frank E. Little
Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2493
Author(s):  
Jussi Sihvo ◽  
Tomi Roinila ◽  
Daniel-Ioan Stroe

The impedance of a Lithium-ion (Li-ion) battery has been shown to be a valuable tool in evaluating the battery characteristics such as the state-of-charge (SOC) and state-of-health (SOH). Recent studies have shown impedance-measurement methods based on broadband pseudo-random sequences (PRS) and Fourier techniques. The methods can be efficiently applied in real-time applications where the conventional electrochemical-impedance spectroscopy (EIS) is not well suited to measure the impedance. The techniques based on the PRS are, however, strongly affected by the battery nonlinearities. This paper presents the use of a direct-synthesis ternary (DST) signal to minimize the effect caused by the nonlinearities. In such a signal, the second- and third-order harmonics are suppressed from the signal energy spectrum. As a result, the effect of the second- and third-order nonlinearities are suppressed from the impedance measurements. The impedance measurements are carried out for a nickel manganese cobalt Li-ion battery cell. The performance of the method is compared to the conventional EIS, as well as to other PRS signals which are more prone to battery nonlinearities. The Kronig–Kramers (K–K) transformation test is used to validate the uniqueness of the measured impedance spectra. It is shown that the measurement method based on the DST produces highly accurate impedance measurements under nonlinear distortions of the battery. The method shows a good K–K test behavior indicating that the measured impedance complies well to a linearized equivalent circuit model that can be used for the SOC and SOH estimation of the battery. Due to the good performance, low measurement time, and simplicity of the DST, the method is well suited for practical battery applications.


2017 ◽  
Vol 40 (3) ◽  
pp. 427-434 ◽  
Author(s):  
G K Kiran ◽  
Tirupathi Rao Penki ◽  
N Munichandraiah ◽  
P Vishnu Kamath

2011 ◽  
Vol 04 (01) ◽  
pp. 65-69 ◽  
Author(s):  
ZHENSHENG HONG ◽  
TONGBIN LAN ◽  
YONGZAN ZHENG ◽  
LILONG JIANG ◽  
MINGDENG WEI

Spinel structural Li2MTi3O8 ( M = Mg, Mg0.5Zn0.5 ) nanowires have been successfully synthesized using titanate nanowires as a precursor and then have been used for the first time as anode materials in a rechargeable Li -ion battery. The cell composed of Li2MgTi3O8 nanowires exhibited a discharge capacity of 232 mAhg-1 at the second cycle, while only 159 mAhg-1 was obtained for the bulk prepared by a solid state reaction. The results of electrochemical impedance spectra indicate that spinel structural Li2MTi3O8 ( M = Mg, Mg0.5Zn0.5 ) nanowires can significantly reduce the charge transfer impedance, leading to enhanced capability of electrochemical lithium storage.


Author(s):  
Ross Drummond ◽  
Chuan Cheng ◽  
Patrick Grant ◽  
Stephen Duncan

Abstract Graded electrodes for Li-ion batteries aim to exploit controlled variations in local electrode microstructure to improve overall battery performance, including reduced degradation rates and increased capacity at high discharge rates. However, the mechanisms by which grading might deliver performance benefit, and under what conditions, are not yet fully understood. A Li-ion battery electrochemical model (a modified Doyle-Fuller-Newman type model capable of generating impedance functions) is developed in which local microstructural changes are captured in order to understand why and when graded electrodes can offer performance benefits. Model predictions are evaluated against experimental electrochemical impedance data obtained from electrodes with micro-scale, controlled variations in microstructure. A region locally enriched with carbon at the electrode/current collector interface is shown to significantly reduce the overpotential distribution across the thickness of a LiFePO$_4$-based Li-ion battery cathode, resulting in a lower charge transfer resistance and impedance. The insights gained from the LiFePO$_4$-based electrodes are generalised to wider design principles for both uniform and graded Li-ion battery electrodes.


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