Rechargeable Calcium–Sulfur Batteries Enabled by an Efficient Borate-Based Electrolyte

Rechargeable metal–sulfur batteries show great promise for energy storage applications because of their potentially high energy and low cost. The multivalent‐metal based electrochemical system exhibits the particular advantage of the feasibility of dendrite‐free metal anode. Calcium (Ca) represents a promising anode material owing to the low reductive potential, high capacity, and abundant natural resources. However, calcium–sulfur (Ca–S) battery technology is in an early R&D stage, facing the fundamental challenge to develop a suitable electrolyte enabling reversible electrochemical Ca deposition, and at the same time, sulfur redox reactions in the system. Herein, a study of a room‐temperature Ca–S battery by employing a stable and efficient calcium tetrakis(hexafluoroisopropyloxy) borate Ca[B(hfip)$_{4}$]$_{2}$ electrolyte is presented. The Ca–S batteries exhibit a cell voltage of ≈2.1 V (close to its thermodynamic value) and good reversibility. The mechanistic studies hint at a redox chemistry of sulfur with polysulfide/sulfide species involved in the Ca‐based system

Performance study of magnesium-sulfur battery using a graphene based sulfur composite cathode electrode and a non-nucleophilic Mg electrolyte

Here we report for the first time the development of a Mg rechargeable battery using a graphene–sulfur nanocomposite as the cathode, a Mg–carbon composite as the anode and a non-nucleophilic Mg based complex in tetraglyme solvent as the electrolyte. The graphene–sulfur nanocomposites are prepared through a new pathway by the combination of thermal and chemical precipitation methods. The Mg/S cell delivers a higher reversible capacity (448 mA h g−1), a longer cyclability (236 mA h g−1 at the end of the 50th cycle) and a better rate capability than previously described cells. The dissolution of Mg polysulfides to the anode side was studied by X-ray photoelectron spectroscopy. The use of a graphene–sulfur composite cathode electrode, with the properties of a high surface area, a porous morphology, a very good electronic conductivity and the presence of oxygen functional groups, along with a non-nucleophilic Mg electrolyte gives an improved battery performance

New Organic Electrode Materials for Ultrafast Electrochemical Energy Storage

Organic materials are both environmentally and economically attractive as potential electrode candidates. This Research News reports on a new class of stable and electrically conductive organic electrodes based on metal porphyrins with functional groups that are capable of electrochemical polymerization, rendering the materials promising for electrochemical applications. Their structural flexibility and the unique highly conjugated macrocyclic structure allows the produced organic electrodes to act as both cathode and anode materials giving access to fast charging as well as high cycling stability. The extreme thermal and chemical stability of the porphyrin‐based organic electrodes and their chemical versatility suggest an important role for these molecular systems in the further development of novel electrochemical energy storage applications

VOCl as a Cathode for Rechargeable Chloride Ion Batteries

A novel room temperature rechargeable battery with VOCl cathode, lithium anode, and chloride ion transporting liquid electrolyte is described. The cell is based on the reversible transfer of chloride ions between the two electrodes. The VOCl cathode delivered an initial discharge capacity of 189 mAh g−1. A reversible capacity of 113 mAh g−1 was retained even after 100 cycles when cycled at a high current density of 522 mA g−1. Such high cycling stability was achieved in chloride ion batteries for the first time, demonstrating the practicality of the system beyond a proof of concept model. The electrochemical reaction mechanism of the VOCl electrode in the chloride ion cell was investigated in detail by ex situ X-ray diffraction (XRD), infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). The results confirm reversible deintercalation–intercalation of chloride ions in the VOCl electrode

Fair Resource Sharing for Dynamic Scheduling of Workflows on Heterogeneous Systems

International audienceScheduling independent workflows on shared resources in a way that satisfy users Quality of Service is a significant challenge. In this study, we describe methodologies for off-line scheduling, where a schedule is generated for a set of knownworkflows, and on-line scheduling, where users can submit workflows at any moment in time. We consider the on-line scheduling problem in more detail and present performance comparisons of state-of-the-art algorithms for a realistic model of a heterogeneous system

Remote detection of invasive alien species

The spread of invasive alien species (IAS) is recognized as the most severe threat to biodiversity outside of climate change and anthropogenic habitat destruction. IAS negatively impact ecosystems, local economies, and residents. They are especially problematic because once established, they give rise to positive feedbacks, increasing the likelihood of further invasions and spread. The integration of remote sensing (RS) to the study of invasion, in addition to contributing to our understanding of invasion processes and impacts to biodiversity, has enabled managers to monitor invasions and predict the spread of IAS, thus supporting biodiversity conservation and management action. This chapter focuses on RS capabilities to detect and monitor invasive plant species across terrestrial, riparian, aquatic, and human-modified ecosystems. All of these environments have unique species assemblages and their own optimal methodology for effective detection and mapping, which we discuss in detail

Erratum to: EuPRAXIA Conceptual Design Report – Eur. Phys. J. Special Topics 229, 3675-4284 (2020), https://doi.org/10.1140/epjst/e2020-000127-8

International audienceThe online version of the original article can be found at http://https://doi.org/10.1140/epjst/e2020-000127-8</A