Reducing Dendrite Growth in Lithium Metal Batteries by Creeping Poiseuille and Couette Flows

Dendrites in lithium metal batteries grow due to instabilities during metal electrodeposition. This paper derives analytical models for electrodeposition with creeping Poiseuille and Couette flows parallel to the two electrodes. The models predict that creeping electrolyte flow parallel to the surface of metal electrode increases the stability of lithium plating by reducing the dendrite growth rate. Moreover, parallel flow reduces the curvature of dendrites leading to flatter electrodeposits, so the dendrites are less likely to penetrate the separator or fracture the Solid Electrolyte Interphase (SEI). For the same average flow rate, Poiseuille flow can be upto two times more stabilizing than Couette flow. However, parallel flows must be many orders of magnitude higher than normal flows for similar reduction in instability. It is also not possible to completely stabilize the metal electrode with creeping parallel flows.