Numerical simulation of lithium dendrite growth in lithium metal batteries: Effect of superimposed AC/DC electric fields on dendrites suppression

The employment of external electric fields is a promising strategy for alleviating lithium dendrite formation during lithium metal battery charging. However, the underlying mechanisms that govern dendrite formation remain unclear. Herein, we present numerical insights into the impact of externally superimposed alternating current (AC) and direct current (DC) electric fields on the suppression of lithium dendrite formation in lithium metal batteries. A theoretical model by coupling the phase field, electric field and ion concentration field is established to predict lithium dendrite growth. Numerical investigations are carried out to understand the fundamental mechanisms of dendrite formation and inhibition in the presence of external AC/DC electric fields. External AC/DC fields applied perpendicular to the internal field enhance Li-ion diffusion by distorting electric field distribution, thereby reducing concentration gradients and local current densities near the anode surface. Similarly, AC/DC fields aligned parallel to the internal field promote uniform lithium deposition by accelerating Li-ion migration and diffusion through an intensified electric field. Consequently, the simultaneous superimposition of AC and DC fields demonstrates an optimal dendrite inhibition effect, reducing the dendrite area to 14.01 % compared to conditions without external fields. This work offers a theoretical basis for lithium dendrite suppression via superimposed electric fields. • Externally superimposed electric fields on mitigating lithium dendrites is proposed. • A multi-physics field coupling model is established to predict the dendrite growth. • The mechanism of dendrite inhibition with external field is numerically illustrated. • The diffusion and migration of lithium ions are critical to dendrite formation. • Combined application of AC and DC fields effectively optimizes dendrite inhibition.