Heterogeneous Nucleation and Growth of Lithium Electrodeposits on Negative Electrodes

Abstract

By starting from fundamental principles, the heterogeneous nucleation and growth of electrodeposited anode materials is analyzed. Thermodynamically, we show that an overpotential-controlled critical radius has to be overcome in order for dendrite formation to become energetically favorable. Kinetically, surface tension and overpotential driving forces define a critical kinetic radius above which an isolated embryo will grow and below which it will shrink. As a result, five regimes of behavior are identified: nucleation suppression regime, long incubation time regime, short incubation time regime, early growth regime, and late growth regime. In the nucleation suppression regime, embryos are thermodynamically unstable and unable to persist. For small overpotentials, below a critical overpotential, 2η○, and between the thermodynamic and kinetic critical radius, a metastable regime exists where the local electrochemically enabled Gibbs-Thomson interactions control the coarsening of the embryos, thus defining the long incubation time regime. In addition, very broad nuclei size distributions are favored. For large overpotentials, above 2η○, a short incubation time regime develops as a result of the small energy barrier and large galvanostatic driving forces. In addition, very narrow size distributions of nuclei are favored. In the early growth regime, thermodynamically and kinetically favored nuclei grow to reach an asymptotic growth velocity. Finally, in the late growth regime, morphological instabilities and localized electric fields dominate the morphology and microstructural evolution of the deposit.

Reliable seawater battery anode: controlled sodium nucleationviadeactivation of the current collector surface

“…[41][42] In particular, applying a low current density is one of the crucial factors for both (i) retardation of the onset time of dendrite The latter, which is expressed as r* = 2γVm/F|η|, where γ is the interfacial energy between solid Na metal and electrolyte, η is the overpotential, Vm is the molar volume, and F is Faraday's constant, suggests an inversely proportional relationship between current density and critical radius; the critical radius of nucleation decreases due to the high overpotential during the metal plating at a high current density. 40,[43][44] Thus, the abundant nuclei (high nucleation rate) on the current collector surface give rise to smaller grain size of plated Na metal, and subsequently the formation of a rough and inhomogeneous surface.…”

Investigating the evolving microstructure of lithium metal electrodes in 3D using X-ray computed tomography

“…NMR and MRI investigations are non-invasive and have been successfully carried out in-situ to capture the formation of dendritic and electrodeposited lithium structures 2,3 ; however the resolution of MRI is limited, typically 100 µm 17 , and the presence of metals can introduce imaging artefacts 18 . There have also been reported attempts to theoretically model different electrodeposited Li growth with regards to their morphologies and feature size distributions [19][20][21][22] .…”

Three-dimensional finite element study on stress generation in synchrotron X-ray tomography reconstructed nickel-manganese-cobalt based half cell

“…Many technological improvements have been made to increase the energy density and cycle life of LIBs, including suppressing dendrites formation [2,3], reducing side reactions [4,5], and preventing thermal runaway [6,7]. One of the critical challenges of LIBs is to enhance the mechanical stability of electrode materials.…”