It is well documented in the scientific literature that lithium electrodeposits grow into elongated "dendritic" structures from the top (tip-controlled) at high current densities and into mossy structures from the base (base-controlled) under low current densities [1,2]. In order to physically understand base-controlled growth, first an analytical model has been developed to incorporate the thermodynamic and kinetic driving forces of lithium to describe the multiphysical electrodeposition kinetics of lithium. Given the charging current density, the following regimes of lithium growth behavior are readily predicted from the analytical framework: (i) thermodynamic suppression regime, (ii) incubation regime, (iii) tip-controlled regime, (iv) base-controlled regime, and (v) mixed growth regime. These regimes explain the experimental observations and provide the kinetic boundaries between tip- and base-controlled growth [3]. Further, numerical calculations demonstrate that high von Mises stresses in localized regions of the lithium whisker extrude lithium and lead to base-controlled growth. In addition, the complex multiphysical dendrite-dendrite electro-chemo-mechanical interactions are rationalized through local electric fields, electrodeposition rates, mechanical stresses, and plastic velocities that are otherwise difficult to visualize in-situ in experiments. Overall, the combined analytical and the numerical frameworks provide multiphysical insight and serve as a design guideline for dendrite-free rechargeable batteries.

[1] O. Crowther, A. C. West. “Effect of electrolyte composition on lithium dendrite growth.” Journal of the Electrochemical Society, 155, A806-A811 (2008).

[2] P. Bai, J. Li, F.R. Brushett, M.Z. Bazant. “Transition of lithium growth mechanisms in liquid electrolytes.” Energy & Environmental Science, 9, 3221-3229 (2016).

[3] A. Jana, R.E. García. “Lithium dendrite growth mechanisms in liquid electrolytes.” Nano Energy, 41, 552-565 (2017).