The Role of Tip Charges in Dendrite Growth on Lithium Electrodes

On metal electrodes, excess charges accumulate on protrusions and dendrites and induce local dipole potentials, which affect the deposition of ions. In particular, alkali ions are deposited at negatively charged electrodes, since their potential of zero charge lies above the deposition potential. Using classical molecular dynamics, we have calculated the potential of mean force for the deposition of lithium ions on the tip of dendrites, which becomes much more favorable in the presence of a negative excess charge. The stochastic aspects of the deposition near dendrites have been investigated using a simple continuum model for the solution. Again, deposition near the tip of the dendrite is favored by a negative excess charge, while the base of the dendrite is shielded by the tip. These calculations provide an atomistic basis for a recently proposed model of dendrite formation.