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

摘要

Understanding the dynamics of lithium metal electrodeposition is crucial todesigning safe and reliable lithium metal anodes. In this study, a grandpotential-based phase-field model is developed to investigate the effect of agas bubble (which forms due to the internal side reactions) on the dynamicsof the dendrite growth during electrodeposition. It is observed that with thepresence 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 awayfrom the anode surface, which can serve as an ion “reservoir” for the dendritegrowth, leading to the tilting of the lithium dendrites toward the bubble. Theeffects 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, thelonger the lithium dendrites will grow. Notably, with a mobile bubble, thedendrite growth can be delayed due to the “stirring effect,” where the motionof the bubble can facilitate the ion migration. This effect is maximized whenthe bubble moving speed is close to the electrodeposition speed. It is hopedthat this study can serve as an example to exploit the effect of extrinsic factorson the dendrite growth dynamics.