LITHIUM ELECTRODE CYCLEABILITY AND MORPHOLOGY DEPENDENCE ON CURRENT-DENSITY

It is known that the cycleability of lithium secondary batteries depends on both charge and discharge current densities. This paper investigates the cycle life and lithium morphology dependence on charge and discharge current densities. The amount of needle-like lithium increases with decreases in discharge current density. The morphology of the needle-like lithium leads to the formation of 'dead lithium' which plays no role in charge/discharge cycles. Localized deposition and dissolution may be the reason for 'dead lithium' formation. The decrease in cycle life with the increase in charge current density is also explained by this mechanism. Furthermore, high rate discharge leads to the recombination of isolated lithium which results in cycle life increase.