Effect of Cathode Composition on Capacity Fade, Impedance Rise and Power Fade in High-Power, Lithium-Ion Cells

Ira Bloom,^a Scott A. Jones,^a Vincent S. Battaglia,^a Gary L. Henriksen,^a Jon P. Christophersen,^bRandy B. Wright,^b Chinh D. Ho,^b Jeffrey R. Belt,^b and Chester G. Motloch^b

^aElectrochemical Technology Program, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439, USA ^bIdaho National Engineering and Environmental Laboratory P.O. Box 1625, Idaho Falls, ID 83415, USA

We tested the effect of Al concentration on the performance of lithium-ion cells. One set of cells contained a LiNi_0.8Co_0.15Al_0.05O₂ cathode and the other, LiNi_0.8Co_0.10Al_0.10O₂. The cells were calendar- and cycle-life tested at several temperatures, with periodic interruptions for reference performance tests that were used to gauge capacity and power fade as a function of time.

The C₁/25 capacity fade in the cells displayed t^1/2 dependence. The capacity fade of the 10% Al-doped cells tested at 4°C was similar to that of the 5% Al-doped cells at 2°C. The impedance rise and power fade were also sensitive to the Al concentration. For the one common temperature investigated (i.e., 4°C), the 10% Al-doped cells displayed higher impedance rise and power fade than the 5% Al-doped cells. Additionally, the time dependence of the impedance rise displayed two distinct kinetic regimes; the initial portion depended on t^1/2 and the final, on t. On the other hand, the 10% Al-doped cells depended on t^1/2 only.

Copyright © 2003 Elsevier Science

Go to Science Direct for full article