Dynamics of the Lithium Metal Electrodeposition: Effects of a Gas Bubble

Understanding the dynamics of lithium metal electrodeposition is crucial to designing safe and reliable lithium metal anodes. In this study, a grand potential-based phase-field model is developed to investigate the effect of a gas bubble (which forms due to the internal side reactions) on the dynamics of the dendrite growth during electrodeposition. It is observed that with the presence of a static gas bubble, the dendrite growth is largely accelerated, owing to the accumulation of lithium ions on the far side of the bubble away from the anode surface, which can serve as an ion "reservoir" for the dendrite growth, leading to the tilting of the lithium dendrites toward the bubble. The effects of the bubble size and distance to the anode are further studied, demonstrating that the larger the bubble size and the closer to the anode, the longer the lithium dendrites will grow. Notably, with a mobile bubble, the dendrite growth can be delayed due to the "stirring effect," where the motion of the bubble can facilitate the ion migration. This effect is maximized when the bubble moving speed is close to the electrodeposition speed. It is hoped that this study can serve as an example to exploit the effect of extrinsic factors on the dendrite growth dynamics.