Temperature Dependence of Capacity and Impedance Data from Fresh and Aged
High-Power Lithium-Ion Cells
D. P. Abraham, E. M. Reynolds, P. L. Schultz, A. N. Jansen, and D. W. Dees
Argonne National Laboratory, Chemical Engineering Division, Argonne,
Illinois 60439, USA
Abstract
Lithium-ion cells for hybrid electric vehicle applications must deliver and
accept current pulses at relatively high rates and over a range of temperatures.
We examined the effect of test temperature from room temperature to 55°C on the
performance of three electrode cells (LiNi0.8Co0.15Al0.05O2
-based positive electrode, Li4/3Ti5/3O4-based
negative electrode, and Li–Sn alloy reference electrode) by galvanostatic
cycling and electrochemical impedance spectroscopy (EIS) measurements.
Increasing the test temperature reduced cell impedance, which improved its power
delivery capability. The higher test temperatures reduced the width of the
midfrequency impedance arc in the positive-electrode EIS data but did not affect
the low-frequency Warburg impedance portion. We discuss the impedance reductions
and capacity gains from the higher temperature measurements in terms of the
electrochemical processes occurring at the electrode/electrolyte interfaces.
©2006 The Electrochemical Society
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