Mechanistic Underpinnings of Morphology Transition in Electrodeposition under the Application of Pulsatile Potential

Abstract

We quantitatively investigate the role of voltage fluctuation in terms of different waveforms on the electrodeposition dynamics and morphology for varying electrolyte concentrations. Dependent on the electrolyte concentration, a wide range of morphologies ranging from highly branched dendrites to comparatively closed packed electrodeposits has been captured. We mechanistically map the deposition dynamics by image analysis and demonstrate the highly porous dendritic dynamics to be independent of external perturbation. Additionally, comparatively closed packed morphological features show significant sensitivity toward the frequency and nature of the waveforms. The results provide fundamental insights into the correlation between the time scales of voltage fluctuation and growth dynamics. We comprehensively analyze the effect of the waveform nature on the average deposition height and show sinusoidal fluctuation to be preferred over square and pulse for metal batteries for lower deposition heights.

An electrodeposition model with surface relaxation predicts temperature and current effects in compact and dendritic film morphologies

“…The models whose microscopic rules allow pore formation provide compact, porous, needle-like, and fractal morphologies; the latter is similar to DLD, where effects of surface diffusion are negligible. However, to our knowledge, none of these kMC models form self-organized dendrites similar to those shown here or similar to leaf-like or featherlike shapes observed in metal electrodeposits 35,[52][53][54][55][56] (shapes that may be alternatively obtained with phase field models 57 ). We understand that this occurs because the collective atom diffusion destroys any organized structures that may appear on the surface of the deposit; such structures tend to coarsen to more compact and larger structures.…”

“…This morphological transition is observed in the electrodeposition of metals such as zinc 50 and copper. 36,51,52 Here we define the thickness z c of the compact layer as the maximal height z in which the normalized density of the deposit is above 0.99 (the density at a given height is defined as the ratio between the number of adatoms at that height and the total number of columns, L 2 ). Fig.…”

“…This morphological transition is observed in the electrodeposition of metals such as zinc 50 and copper. 36,51,52…”

The Role of Pulse Duty Cycle and Frequency on Dendritic Compression

“…Setup. In order to replicate the electrodeposition in batteries, we have fabricated a laboratory-made electrochemical cell, composed of symmetric copper wire electrodes, 55 because of their nontoxicity and environmental friendliness. The experimental setup shown in Figure 1a consists of a transparent plastic cuvette (4.5 cm × 1 cm × 1 cm) that functions as an electrolytic cell.…”

“…More details of the experimental setup are available in the previous publication. 55 After each experiment, the cuvette is cleaned with isopropyl alcohol (IPA), followed by deionized water (DI, Milli-Q, 99.8%), and rinsed with the electrolyte solution to be used for performing the next experiment. The copper wires are cleaned with acetone and ethanol to remove any oily residue present on the surface.…”