Title of article :
The meaning of impedance measurements of LiFePO4 cathodes: A linearity study
Author/Authors :
Miran Gaberscek، نويسنده , , Robert Dominko، نويسنده , , Janez Jamnik، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2007
Pages :
5
From page :
944
To page :
948
Abstract :
The validity of impedance response measurements within the plateau region of galvanostatic charge–discharge curve of LiFePO4 cathode material was studied in detail. Based on (i) measurement of dependence of impedance response on the mode (voltage, current) and amplitude of excitation, (ii) analysis of higher harmonics of the response signal, and (iii) comparison of impedance response with time-domain measurements, we conclude that above a certain critical frequency that lies in the range 1–100 mHz, the impedance response of LiFePO4 satisfies the criteria of linearity and time invariance (LTI). At lower frequencies the impedance response becomes scattered and does not satisfy the LTI criteria anymore. The critical frequency at which the transition from LTI to non-LTI behaviour occurs, depends on the amplitude of current excitation signal.
Keywords :
Non-linearity , Phase transformation , diffusion , LiFePO4 , Impedance spectroscopy , Kinetics
Journal title :
Journal of Power Sources
Serial Year :
2007
Journal title :
Journal of Power Sources
Record number :
442198
Link To Document :
بازگشت