Ionic liquids are salts that are liquid at low temperature (<100 degrees C) which represent a new class of solvents with nonmolecular, ionic character. Even though the first representative has been known since 1914, ionic liquids have only been investigated as solvents for transition metal catalysis in the past ten years. Publications to date show that replacing an organic solvent by an ionic liquid can lead to remarkable improvements in well-known processes. Ionic liquids form biphasic systems with many organic product mixtures. This gives rise to the possibility of a multiphase reaction procedure with easy isolation and recovery of homogeneous catalysts. In addition, ionic liquids have practically no vapor pressure which facilitates product separation by distillation. There are also indications that switching from a normal organic solvent to an ionic liquid can lead to novel and unusual chemical reactivity. This opens up a wide field for future investigations into this new class of solvents in catalytic applications.

Ionic Liquids-New "Solutions" for Transition Metal Catalysis.

Ionic liquids as electrolytes

Synthetic Principles for Bandgap Control in Linear pi-Conjugated Systems.

A short history of ionic liquids—from molten salts to neoteric solvents

The past few decades have shown a rapid and continuous exhaustion of the available energy resources which may lead to serious energy global crises. Researchers have been focusing on developing new and renewable energy resources to meet the increasing fuel demand and reduce greenhouse gas emissions. A surge of research effort is also being directed towards replacing fossil fuel based vehicles with hybrid and electric alternatives. Energy storage is now seen as a critical element in future "smart grid and electric vehicle" applications. Electrochemical energy storage systems offer the best combination of efficiency, cost and flexibility, with redox flow battery systems currently leading the way in this aspect. In this work, a panoramic overview is presented for the various redox flow battery systems and their hybrid alternatives. Relevant published work is reported and critically discussed. A comprehensive study of the available technologies is conducted in terms of technical aspects as well as economic and environmental consequences. Some of the flow battery limitations and technical challenges are also discussed and a range of further research opportunities are presented. Of the flow battery technologies that have been investigated, the all-vanadium redox flow battery has received the most attention and has shown most promise in various pre-commercial to commercial stationary applications to date, while new developments in hybrid redox fuel cells are promising to lead the way for future applications in mechanically and electrically "refuelable" electric vehicles.

https://iopscience.iop.org/article/10.1149/1.3599565/pdf

Progress in Flow Battery Research and Development

The present invention relates to the use of porous structures comprising sulfur in electrochemical cells. Such materials may be useful, for example, in forming one or more electrodes in an electrochemical cell. For example, the systems and methods described herein may comprise the use of an electrode comprising a conductive porous support structure and a plurality of particles comprising sulfur (e.g., as an active species) substantially contained within the pores of the support structure. The inventors have unexpectedly discovered that, in some embodiments, the sizes of the pores within the porous support structure and/or the sizes of the particles within the pores can be tailored such that the contact between the electrolyte and the sulfur is enhanced, while the electrical conductivity and structural integrity of the electrode are maintained at sufficiently high levels to allow for effective operation of the cell. Also, the sizes of the pores within the porous support structures and/or the sizes of the particles within the pores can be selected such that any suitable ratio of sulfur to support material can be achieved while maintaining mechanical stability in the electrode. The inventors have also unexpectedly discovered that the use of porous support structures comprising certain materials (e.g., metals such as nickel) can lead to relatively large increases in cell performance. In some embodiments, methods for forming sulfur particles within pores of a porous support structure allow for a desired relationship between the particle size and pore size. The sizes of the pores within the porous support structure and/or the sizes of the particles within the pores can also be tailored such that the resulting electrode is able to withstand the application of an anisotropic force, while maintaining the structural integrity of the electrode.

Electrochemical cells comprising porous structures comprising sulfur

Systems and methods for accurately determining the state of charge and the relative age of lithium sulfur batteries are provided. The cell resistance and taper input charge of a particular type of lithium sulfur battery are respectively measured to determine the state of charge and age of the battery.

Lithium sulfur rechargeable battery fuel gauge systems and methods

Alkali metal electrochemical reductions at a mercury film electrode (MFE) were studied in AlCl 3 :MEIC (MEIC=1-methyl-3-ethylimidazolium chloride) molten salts buffered to a neutral composition with MCl (M=Li, Na, K, Rb, and Cs). The MFE was formed by mercury deposition on a 127-μm iridium disk electrode. At the Ir-MFE, the reduction potentials for the Li, Na, K, Rb, and Cs amalgams were observed at -1.16, -1.26, -1.62, -1.67, and -1.75 V (vs. Al/Al(III)), respectively

Alkali Metal Reduction Potentials Measured in Chloroaluminate Ambient‐Temperature Molten Salts

Electrochemical cells including anode compositions that may enhance charge-discharge cycling efficiency and uniformity are presented. In some embodiments, alloys are incorporated into one or more components of an electrochemical cell, which may enhance the performance of the cell. For example, an alloy may be incorporated into an electroactive component of the cell (e.g., electrodes) and may advantageously increase the efficiency of cell performance. Some electrochemical cells (e.g., rechargeable batteries) may undergo a charge/discharge cycle involving deposition of metal (e.g., lithium metal) on the surface of the anode upon charging and reaction of the metal on the anode surface, wherein the metal diffuses from the anode surface, upon discharging. In some cases, the efficiency and uniformity of such processes may affect cell performance. The use of materials such as alloys in an electroactive component of the cell have been found to increase the efficiency of such processes and to increase the cycling lifetime of the cell. For example, the use of alloys may reduce the formation of dendrites on the anode surface and/or limit surface development.

Lithium alloy/sulfur batteries

A series of 2,5-bis(2-thienyl)pyrroles has been synthesized in which the α-thiophene protons and/or the β-pyrrole protons have been replaced by Me or Br substituents. A systematic electrochemical investigation of these compounds has yielded rate constants of 36 000 M -1 s -1 for linear couplings of the electrochemically generated cation radicals and 14 000-17 000 M -1 s -1 for branched coupling reactions of the cation radicals. These results constitute the first kinetic evidence foir appreciable branched coupling of the electrochemical radical cations of an oligomer precursor of a conducting polymer

Chariclea Scordilis-Kelley

Papers

Electrochemical cells comprising porous structures comprising sulfur

Lithium sulfur rechargeable battery fuel gauge systems and methods

Alkali Metal Reduction Potentials Measured in Chloroaluminate Ambient‐Temperature Molten Salts

Lithium alloy/sulfur batteries

A mechanistic study of the electrochemical oxidation of 2,5-bis(2-thienyl)pyrroles