Atomistic Studies on Water-Induced Lithium Corrosion.

It is well known that lithium reacts violently with water under the release of molecular hydrogen and the formation of lithium hydroxide. In this work, the initial mechanisms for the surface reactions of metallic lithium with water from the gas phase were investigated by means of periodic density functional theory calculations. For this purpose, adsorption/absorption structures and diffusion and dissociation processes of hydrogen, OH, and H2 O on low-index metallic lithium surfaces were investigated. Through thermodynamic and kinetic considerations, negatively charged centers on the surface were identified as the origin of hydrogen formation. The strikingly low reaction barriers for the reaction at these centers implied a self-supporting effect of hydrogen evolution and the associated lithium degradation.

Properties of the Space Charge Layers Formed in Li-Ion Conducting Glass Ceramics.

For years, the space charge layer formation in Li-conducting solid electrolytes and its relevance to so-called all solid-state batteries have been controversially discussed from experimental and theoretical perspectives. In this work, we observe the phenomenon of space charge layer formation using impedance spectroscopy at different electrode polarizations. We analyze the properties of these space charge layers using a physical equivalent circuit describing the response of the solid electrolytes and solid/solid electrified interfaces under blocking conditions. The elements corresponding to the interfacial layers are identified and analyzed with different electrode metals and applied biases. The effective thickness of the space charge layer was calculated to be ∼60 nm at a bias potential of 1 V. In addition, it was possible to estimate the relative permittivity of the electrolytes, specific resistance of the space charge layer, and the effective thickness of the electric double layer (∼0.7 nm).