Structural and morphological evolution of lead dendrites during electrochemical migration.

The electrochemical deposition and dissolution of lead on gold electrodes immersed in an aqueous solution of lead nitrate were studied in situ using a biasing liquid cell by transmission electron microscopy (TEM). We investigate in real time the growth mechanisms of lead dendrites as deposited on the electrodes under an applied potential. TEM images reveal that lead dendrites are developed by the fast protrusion of lead branches in the electrolyte and tip splitting. And, the fast growing tip of the dendritic branch is composed of polycrystalline nanograins and it develops into a single crystalline branch eventually. This study demonstrated unique electrochemical growth of single crystal dendrites through nucleation, aggregation, alignment and attachment of randomly oriented small grains. Additionally, we found the lead concentration in the electrolyte drastically influences the morphology of dendritic formation.