Potential dependence of the step line tension on surfaces in contact with an electrolyte

Influence of electric fields on metal self-diffusion barriers and its consequences on dendrite growth in batteries

Based on the results of periodic density functional theory calculations, we have recently proposed that the height of self-diffusion barriers can serve as a descriptor for dendrite growth in batteries [M. Jäckle et al., Energy Environ. Sci. 11, 3400 (2018)]. However, in the determination of the self-diffusion barriers, the electrochemical environment has not been taken into account. Still, due to the presence of electrical double layers at electrode/electrolyte interfaces, strong electric fields can be present close to the interfacial region. In a first step toward including the electrochemical environment, we have calculated barriers for terrace-diffusion on lithium, magnesium, and silver surfaces and across-step self-diffusion on lithium in the presence of electric fields. Whereas the electric field effect is more pronounced on a stepped surface than on flat terraces, overall we find a negligible influence of electric fields on self-diffusion barriers which we explain by the good screening properties of metals.

X-Ray Scattering and Imaging Studies of Electrode Structure and Dynamics

We will review structures and dynamics of electrode interfaces studied in situ using x-ray scattering and imaging techniques. The examples cover single-crystal and nanocrystal structures relevant to electrocatalytic activities, anodic oxidation and corrosion, aqueous dissolution reactions, surface reconstructions, and surface modifications by under potential deposition. The x-ray techniques include the widely used traditional surface x-ray scattering, such as crystal truncation rods and x-ray reflectivity, as well as recently developed resonance surface scattering, coherent surface x-ray photon correlation spectroscopy, coherent x-ray Bragg diffraction imaging, and surface ptychography. Results relevant to various electrochemical phenomena will be highlighted.

Charge-induced equilibrium dynamics and structure at the Ag(001)–electrolyte interface

The applied potential dependent rate of atomic step motion of the Ag(001) surface in weak NaF electrolyte has been measured using a new extension of the technique of X-ray Photon Correlation Spectroscopy (XPCS).

Electrodeposition of metal wires onto a molecular scale template: an in situ investigation

We have demonstrated that the intrinsic nanometer length scales of two-dimensional molecular assemblies can be exploited to electrodeposit metal nanostructures with regular spacing and orientation. We observed evidence for preferential deposition of metals into parallel lines on Au(111) surface with a periodicity of 4.5 nm as determined by the hemimicelles formed by sodium dodecylsulfate. The preferential deposition of metals in molecular templates was achieved under optimal electrode potentials and ionic concentrations. The observed metal structures provide insight into the interactions between metal atoms, organic functional groups as well as the aqueous environment. Understanding and tailoring these interactions will lead to more precise control and new strategies for nanoscale placement and for connecting organic molecules to metal nanostructures.

Step line tension on a metal electrode

The step line tension in electrochemical systems differs conceptually from the line tension on metals in the vacuum because it refers to different boundary conditions. A procedure is established for calculating the electrochemical line tension and is applied to a novel model of the interface comprising both a stepped metal electrode and an electrolyte solution. To first order, the potential dependence of the line tension is governed by the energy of the step dipole in the electric field of the space charge in the solution.