LITHIUM ELECTRODE MORPHOLOGY DURING CYCLING IN LITHIUM CELLS

Lithium electrode surface morphologies during cycling were measured in LiAsF6-ethylene carbonate (EC)/2-methyl-tetrahydrofuran (2MeTHF) and LiAsF6-2MeTHF electrolytes. Particulate and needle-like Li were observed on the Li electrode after cycling. Although the particulate Li could be stripped during discharge, much of the needle-like Li remained. It appears that the needle-like Li tends to become 'dead-Li' and is responsible for the loss of cycling of lithium electrodes.