Dendritic growth mechanisms in lithium/polymer cells

Direct in situ observation of dendritic electrodeposition of lithium has been performed in symmetrical lithium/PEO-LiTFSI cells under galvanostatic conditions. Our experimental set-up allows us to measure simultaneously the variation of the cell potential, the evolution of the dendrites, and the variation of the ionic concentration in the electrolyte around the dendrites. Depending on current density, we observe two different regimes for the dendritic growth: at high current density, dendrites start when the ionic concentrations drop to zero at the negative electrode, whereas at low current density, local inhomogeneities seem to play a major role. (C) 1999 Elsevier Science S.A. All rights reserved.