Effect of interfacial reaction rate on the morphogenesis of nanostructured coatings in a simulated electrodeposition process

Abstract

Brownian dynamics simulations (BDSs) are performed to investigate the influence of interfacial electrochemical reaction rate on the evolution of coating morphology on circular fibres. The boundary condition for the fluid phase concentration, representing the balance between the rates of interfacial reaction and transport of ions by bulk diffusion, is incorporated into the BDS by using a reaction probability, P(s). Different modes of growth, ranging from diffusion limited ([Formula: see text]) to reaction controlled [Formula: see text], are studied. It is found that, consistent with experimental observations, two distinct morphological regimes exist, with a dense and uniform structure for [Formula: see text] (reaction limited deposition (RLD)) and an open and porous one as [Formula: see text] (diffusion limited deposition (DLD)). An analysis of the fractal dimension indicates that this morphological transition occurs at P(s)≈0.3. Long-time power-law scalings for the evolution of thickness [Formula: see text] and roughness (ξ) of the coating exist, i.e. [Formula: see text] with 0.86≤α≤0.91 and 0.56≤β≤0.93 for 0.01≤P(s)≤1. These values are different from those reported for sequential, pseudo-time lattice simulations on planar surfaces, signifying the importance of multiparticle dynamics and surface curvature. The internal structure and porosity of the coating are characterized quantitatively by the radial density profile, pair correlation function, two-point probability function, void distribution function and pore area distribution. For RLD the radial density, ρ(n), remains nearly constant, while for DLD ρ(n) follows a power law, [Formula: see text]. The coating exhibits short ranged order in the RLD regime while a long range order is created by DLD. The void distribution function becomes broader with increasing P(s), indicating that in the RLD regime the coating consists of small and spherical pores, while in the DLD regime large and elongated pores are obtained. The pore area distribution shows narrower distributions in DLD for small pores, while the area of the largest pore increases by nearly three orders of magnitude as one moves from the RLD to the DLD regime. Such morphological diversity could be potentially exploited for applications such as percolation, catalysis and surface protection.

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

“…If the attempt succeeds, the cation is irreversibly switched to a reduced metal atom and is deposited onto the electrode or other metal atoms. Upon deposition, the position of the new metal atom is adjusted using the following protocol to account for the finite volume of the metal atoms . In a first step, if the volume of the new metal atom overlaps with that of the hemispherical electrode, then the position of the atom is radially shifted outward until this overlap is eliminated.…”

“…Upon deposition, the position of the new metal atom is adjusted using the following protocol to account for the finite volume of the metal atoms. 13 In a first step, if the volume of the new metal atom overlaps with that of the hemispherical electrode, then the position of the atom is radially shifted outward until this overlap is eliminated. In a second step, if the volume of the new metal atom overlaps with that of at least one other metal atom, one of the existing metal atoms is randomly chosen, and the position of the new metal atom is shifted along the vector r n − r o until the overlap is eliminated; here, r n and r o indicate the respective positions of the new and previously plated metal atoms.…”

Substrate effects on Li+ electrodeposition in Li secondary batteries with a competitive kinetics model

“…Several meaningful and fundamental models concerning the mechanism of Li dendrite formation have been proposed in the last 40 years. Examples of these models include the ''surface-tension model'' proposed by Barton and Bockris in the 1960s, [34][35][36][37] the ''Brownian statistical simulation model'' in the 1980s, [38][39][40][41][42] the ''Chazalviel electromigration-limited model'' developed in the 1990s, [43][44][45][46][47] and Yamaki's theory in the 1990s. 48 These mechanistic models explain specific situations from different perspectives, with respective superiorities but also limitations.…”

Role of a Solid–Electrolyte Interphase in the Dendritic Electrodeposition of Lithium: A Brownian Dynamics Simulation Study

“…In this perspective, we use Brownian dynamics (BD) simulation to elucidate the suppressive role of a SEI layer in the dendritic deposition of Li. The BD modeling enables us to examine the surface morphology with atomistic details, ,,, which is not feasible in the continuum models , including the phase field methods. − Moreover, the dendrites close to experimental length (μm) and time scales (min) can be simulated, which is a daunting task in the first-principles , or molecular dynamics simulations. , The dendrites in the pulse-charging experiment were successfully reproduced by the BD simulation.…”