Suppression of Dendrite Formation via Pulse Charging in Rechargeable Lithium Metal Batteries

Abstract

We introduce a coarse-grained simulation model for the reductive deposition of lithium cations in secondary lithium metal batteries. The model accounts for the heterogeneous and nonequilibrium nature of the electrodeposition dynamics, and it enables simulation of the long timescales and lengthscales associated with metal dendrite formation. We investigate the effects of applied overpotential and material properties on earlystage dendrite formation, as well as the molecular mechanisms that govern this process. The model confirms that dendrite formation propensity increases with the applied electrode overpotential, and it demonstrates that application of the electrode overpotential in time-dependent pulses leads to dramatic suppression of dendrite formation while reducing the accumulated electrode on-time by as much as 96%. Moreover, the model predicts that time dependence of the applied electrode overpotential can lead to positive, negative, or zero correlation between cation diffusivity in the solid−electrolyte interphase (SEI) and dendrite formation propensity. Analysis of the simulation trajectories reveals that dendrite formation emerges from a competition between the timescales for cation diffusion and reduction at the anode/SEI interface, with lower applied overpotentials and shorter electrode pulse durations shifting this competition in favor of lower dendrite formation propensity. This work provides a molecular basis for understanding and designing pulsing waveforms that mitigate dendrite formation while minimally affecting battery charging times.

Pulsed Current Electrodeposition of Silicon Thin Films Anodes for Lithium Ion Battery Applications

“…However, the oxygen content in the film decreases from PEDSi-0 Hz to PEDSi-500 Hz and then increases from PEDSi-500 Hz to PEDSi-5000 Hz. As explained previously at lower frequencies, the growth of Si thin films is guided by relative timescales available for diffusion and reduction of Si 4+ ions [47,48]. Due to the enhanced diffusion of Si 4+ ions during the OFF TIME the Si content increases and the oxygen content decreases from PEDSi-0 Hz to PEDSi-500 Hz.…”

“…During longer ON TIME, the timescale for reduction is more favorable than that for diffusion of Si 4+ hence, giving a low-density deposition with large grains as in case of PEDSi-0 and PEDSi-500. However, the Si 4+ diffusion is favored upon decreasing the ON TIME allowing the ions to penetrate into the diffusion structure giving more uniform and denser thin films (PEDSi-1000 Hz) thus, improving the mechanical strength of the Si thin film as well as that of the Si-Cu interface [47,48]. At higher pulse frequencies (PEDSi-1000 Hz to PEDSi-5000 Hz), the pulses are much shorter, i.e., both ON TIME and OFF TIME are of short duration during which the double layer does not have sufficient time to fully charge during ON TIME and to discharge during the OFF TIME.…”

Li‐Ion Batteries and Beyond: Future Design Challenges

“…Most metal electrodes showed dendritic growth of the electrodeposited metal as the current density approaches the limiting current density, which indicates that the electrodeposition morphology strongly depends on the current distribution on the electrode. [9] M. Arakawa et al [10] and M. Z. Mayers et al [11] successfully demonstrated that the amount of needle-like Li increased significantly when the deposition current density increased.…”

Lithium Dendrite Inhibition on Post-Charge Anode Surface: The Kinetics Role

“…This phenomenon eventually leads to short-circuiting, overheating the cell and possible ignition of the organic electrolyte as well as creating isolated 'dead lithium' crystals. [2] The current reports have investigated the effect of charging method, [3,4] current density [5][6][7], electrode surface morphology [8][9][10], solvent and electrolyte chemical composition [11][12][13],electrolyte concentration [5,14] on dendrite growth. Other methods include the use of powder electrodes [15] and adhesive polymers [16].…”