Reconstruction and electronic properties of β-Li3PS4 |Li2S interface

The morphology and properties of the interface between solid electrolyte and electrode have important impacts on all-solid-state lithium-sulfur batteries’ performance. We used the first-principles calculations to explore the interface between Li2S cathode and β-Li3PS4 (lithium thiophosphate, LPS) solid electrolyte, including lattice structure, mechanical, electrical properties, interface contact type, and charge distribution in real space. It is found that the interface is significantly reconstructed, and the Li atoms at the interface move mainly parallel to the interface plane. The interface density states introduce metallic properties, mainly contributed by the Li-s and S-s, -p orbitals in Li2S and S-p orbitals in LPS. The highest occupied molecular orbitals of the LPS electrolyte are lower than the electrochemical potential (Fermi level) of the Li2S cathode, thus the electrolyte and cathode materials are reasonable and stable in thermodynamics. Interface density of states shows electrons on the interface do not penetrate from Li2S into LPS, and do not leak electrons to cause electron conduct in LPS. Besides, the interface is an n-type Schottky barrier with a barrier value of 1.0 eV. The work-function of the interface indicates that there is a space charge layer by the redistribution of electrons, which is in agreement with the result of interface charge density difference. The electron/hole pairs will be separate, realizing high current charge and discharge capability because of the space charge layer.

Observational study of tornadic cells that hit Corsica during the ADRIAN storm on the 29th October 2018

<p><span><span>The north-western Mediterranean basin often experiences thunderstorms with heavy precipitation, strong wind, lightning activity </span><span>and sometimes waterspouts/tornadoes</span><span>. One of the objectives of the EXAEDRE (EXploiting new Atmospheric Electricity Data for Research and the Environment) project is to better monitor the thunderstorms in this area through a better understanding of the physical processes that drive the dynamics, the microphysics and the electrical activity of the convective systems. </span><span>C</span><span>haracteristics </span><span>of the electrical activity </span><span>such as flash rate, charge layer </span><span>distribution</span><span> or flash polarity are good proxies for thunderstorm monitoring and good evidences of the storm severity.</span></span></p><p><span>The 29<sup>th</sup> October 2018, an intense trough developed over Mediterranean Sea between Balearic Islands and Corsica. This storm, called ADRIAN, produced several hazards (heavy precipitation, strong winds, intense lightning activity and hailstorm) in Corsica. Two tornadoes and one waterspout were observed in the morning at Porto Vecchio (EF2 tornado and waterspout) and Aleria (EF1 tornado), causing significant damages.</span></p><p><span>In this study, we take a look at electrical and microphysical characteristics of the two tornadic cells. </span><span>For that, observations of the LMA (Lightning Mapping Array) SAETTA network, deployed in Corsica, are used to document in 3D the total lightning activity. Complementary 2D lightning observations recorded by the French national lightning detection network METEORAGE are also investigated. We also use weather radar data from the Météo France network. A clustering algorithm is applied on both the lightning and radar data to identify and track the cells to document the evolution of several lightning-related and microphysical characteristics during the lifetime of each cell. We also applied a new method based on lightning leader velocity to automatically infer the vertical and horizontal structure of the electrical charge regions within each electrical cell.</span></p><p><span><span>We first introduce the different observations and methodologies applied here. Then the main electrical properties </span></span><span><span>of the tornadic cells </span></span><span><span>(e.g. flash duration, vertical flash extension, charge layer, flash type and polarity) </span></span><span><span>and microphysical characteristics </span></span><span><span>as well as their temporal evolution are presented. </span></span><span><span>Overall, t</span></span><span><span>h</span></span><span><span>e </span></span><span><span>studied electrical cells</span></span><span><span> produced few cloud-to-ground lightning </span></span><span><span>flashes</span></span><span> </span><span><span>p</span></span><span><span>redominantly of negative polarity. </span></span><span><span>The peaks of electrical activity occurred when tornadoes </span></span><span><span>hit the land and </span></span><span><span>these storms presented </span></span><span><span>all </span></span><span><span>an anomalous charge structure. </span></span></p>