Montmorillonite/Poly(Pyrrole) for Low-Cost Supercapacitor Electrode Hybrid Materials.

Conductive polymers such as polypyrrole have been widely used as pseudo-capacitive electrodes for supercapacitors. This work demonstrates a simple method to improve the performance of conductive polymer electrodes by adding montmorillonite in order to perform capacitive behavior. Conductive composite polymers (CCPs) based on montmorillonite/polypyrrole (MMT/PPy(Cl)) have been synthesized by polymerization using FeCl as an oxidizing agent.

Lithium-Ion Battery Cathode Recycling through a Closed-Loop Process Using a Choline Chloride-Ethylene Glycol-Based Deep-Eutectic Solvent in the Presence of Acid.

This study evaluates the ability of a choline chloride:ethylene glycol-based deep eutectic solvent (DES) to dissolve lithium cobalt oxide (LCO) which is used as a cathode active material in Li-ion batteries. Both a commercial powder and spent cathodes have been used. It was demonstrated that if HCl is added in a small proportion, a rapid and efficient LCO dissolution can be achieved.

Correlation of electrochemical and investigations of iron poly-bipyridine coordination complexes for battery applications: impact of the anionic environment and the local geometries of the redox complexes on the electrochemical response.

Although they exhibit huge versatility, coordination complexes have been rarely investigated in the field of cathode materials for batteries. Despite their relatively high molecular mass, according to the nature of the metallic center and that of the ligand, the E° value and the electron transfer kinetics can be adjusted to develop a performant material compatible with the electrolyte. Here, we propose to investigate FeII poly-bipyridine complexes with a view to check the impact of the nature of the electrolyte as well as the influence of the distance between two redox centers when polymerized on the electrochemical response in battery conditions.

Effect of standard light illumination on electrolyte's stability of lithium-ion batteries based on ethylene and di-methyl carbonates.

Combining energy conversion and storage at a device and/or at a molecular level constitutes a new research field raising interest. This work aims at investigating how prolonged standard light exposure (A.M.

Magnesium Anthracene System-Based Electrolyte as a Promoter of High Electrochemical Performance Rechargeable Magnesium Batteries.

The development of efficient, inexpensive, and safe rechargeable batteries for large-scale environmentally benign cells is one of the key requirements to accommodate and satisfy various technological applications. To date, the development of magnesium battery as a promising candidate for next-generation battery systems has been hindered by the lack of high performance and stable electrolyte. In this work, we have developed an original, safe, and high-performance class of electrolytes based on a simple mixture of commercially available compounds, that is, Mg(TFSI), anthracene, MgCl, and diglyme solvent.

Electrolyte Based on Easily Synthesized, Low Cost Triphenolate-Borohydride Salt for High Performance Mg(TFSI)-Glyme Rechargeable Magnesium Batteries.

A new class of electrolyte based on TFSI and triphenolate-borohydride anions was designed and produced which fulfill all requirements of easy synthesis, high ionic conductivity, wide potential window, and noncorrosion of Al current collector. The electrolyte composed of magnesium triphenolate borohydride and Mg(TFSI) in glyme simultaneously displays a high conductivity of 5.5 mS cm at 25 °C and a reversible Mg plating/stripping with high current density and Coulombic efficiency at room temperature.

Excited-state spectroscopic investigations of multinuclear complexes based on [Ru(bpy)3](2+) moieties connected to 2,2'-bipyridine and 2,2';6',2''-terpyridine ligands.

A number of multinuclear assemblies based on [Ru(bpy)3](2+) photosensitive moieties covalently linked to Fe(II), Co(II) or Zn(II) polypyridyl complexes are investigated regarding their initial and thermally equilibrated excited states. Ground state absorption and vibrational spectroscopic techniques are carried out, along with resonance Raman, transient absorption, and time resolved resonance Raman measurements. These methods are also supplemented by computational modelling.

New insight into the working mechanism of lithium-sulfur batteries: in situ and operando X-ray diffraction characterization.

In order to improve the electrochemical performances of lithium-sulfur batteries, it is crucial to understand profoundly their working mechanism and the limitation factors. This communication presents synchrotron-based in situ XRD studies of structural modifications occurring inside the cell upon cycling, since the active material changes constantly its form between solid and liquid phases.

Lithium/sulfur cell discharge mechanism: an original approach for intermediate species identification.

The lithium/sulfur battery is a promising electrochemical system that has a high theoretical capacity of 1675 mAh g(-1), but its discharge mechanism is well-known to be a complex multistep process. As the active material dissolves during cycling, this discharge mechanism was investigated through the electrolyte characterization. Using high-performance liquid chromatography, UV-visible absorption, and electron spin resonance spectroscopies, we investigated the electrolyte composition at different discharge potentials in a TEGDME-based electrolyte.

Structure-properties relationships of lithium electrolytes based on ionic liquid.

Low-melting ionic liquid, IL, based on small aliphatic quaternary ammonium cations ([R(1)R(2)R(3)NR](+), where R(1), R(2), R(3) = CH(3) or C(2)H(5), R = C(3)H(7), C(4)H(9), C(6)H(13), C(8)H(17), CF(3)C(3)H(6)) and imide anion were prepared and characterized. The physicochemical and electrochemical properties of these ILs, including melting point, glass transition, and degradation temperatures; viscosity; density; ionic conductivity; diffusion coefficient; and electrochemical stability, were determined. Heteronuclear Overhauser NMR spectroscopy experiments were also performed to point out the presence of pair correlation between the different moieties.

Mononuclear Mn(III) and Mn(IV) bis-terpyridine complexes: electrochemical formation and spectroscopic characterizations.

The electrochemical behavior of two mononuclear Mn(II) bis-terpyridine complexes, [Mn(II)(L)(2)](2+) (L = terpy (2,2':6',2''-terpyridine) and (t)Bu(3)-terpy (4,4',4''-tritert-butyl-2,2':6',2''-terpyridine)), has been investigated in dry CH(3)CN. Under these conditions, the cyclic voltammograms of these complexes exhibit not only the well-known Mn(II)/Mn(III) oxidation system but also a second metal-based oxidation one, corresponding to the Mn(III)/Mn(IV) redox couple. These oxidative processes are located at E(1/2) = +0.

An unusual stable mononuclear Mn(III) bis-terpyridine complex exhibiting Jahn-Teller compression: electrochemical synthesis, physical characterisation and theoretical study.

The mononuclear manganese bis-terpyridine complex [Mn(tolyl-terpy)(2)](X)(3) (1(X)(3); X=BF(4), ClO(4), PF(6); tolyl-terpy=4'-(4-methylphenyl)-2,2':6',2"-terpyridine), containing Mn in the unusual +III oxidation state, has been isolated and characterised. The 1(3+) ion is a rare example of a mononuclear Mn(III) complex stabilised solely by neutral N ligands. Complex 1(3+) is obtained by electrochemical oxidation of the corresponding Mn(II) compound 1(2+) in anhydrous acetonitrile.

Photoredox vs. energy transfer in a Ru(II)-Fe(II) supramolecular complex built with an heteroditopic bipyridine-terpyridine ligand.

A trinuclear [[Ru(II)(bpy)(2)(bpy-terpy)](2)Fe(II)](6+) complex (I) in which a Fe(II)-bis-terpyridine-like centre is covalently linked to two Ru(II)-tris-bipyridine-like moieties by a bridging bipyridine-terpyridine ligand has been synthesised and characterised. Its electrochemical, photophysical and photochemical properties have been investigated in CH(3)CN and compared with those of mononuclear model complexes. The cyclic voltammetry of (I) exhibits, in the positive region, two successive reversible oxidation processes, corresponding to the Fe(III)/Fe(II) and Ru(III)/Ru(II) redox couples.

Di(micro-oxo) binuclear manganese(III,IV) poly(bipyridyl) complexes bearing four ruthenium(II) photoactive units: synthesis, characterization, and photoinduced electron-transfer properties.

In order to model the photoinduced electron-transfer reactions from the manganese cluster to the photoactive P680 chlorophylls in photosystem II, three heterohexanuclear complexes, [Mn2III,IVO2[RuII(bpy)2(Ln)]4]11+ [bpy = 2,2'-bipyridine, n = 2 (1a), 4 (1b), 6 (1c)], in which one MnIII,IV(micro-O)2 center is covalently linked to four RuII(bpy)3-like moieties by bridged bis(bipyridine) Ln ligands, have been synthesized and characterized. The electrochemical, photophysical, and photochemical properties of these complexes have been investigated in CH3CN. The cyclic voltammograms and rotating-disk electrode curves of the three complexes show the presence of two very close successive reversible oxidation processes corresponding to the Mn2III,IV/Mn2IV,IV and RuII/RuIII redox couples (estimated E1/2 approximately 0.

Tetranuclear polybipyridyl complexes of Ru(II) and Mn(II), their electro- and photo-induced transformation into di-mu-oxo Mn(III)Mn(IV) hexanuclear complexes.

Three heterotetranuclear complexes, [{Ru(II)(bpy)(2)(L(n))}(3)Mn(II)](8+) (bpy = 2,2'-bipyridine, n = 2, 4, 6), in which a Mn(II)-tris-bipyridine-like centre is covalently linked to three Ru(II)-tris-bipyridine-like moieties using bridging bis-bipyridine L(n) ligands, have been synthesised and characterised. The electrochemical, photophysical and photochemical properties of these complexes have been investigated in CH(3)CN. The cyclic voltammograms of the three complexes exhibit two successive very close one-electron metal-centred oxidation processes in the positive potential region.

Electrochemical and chemical formation of [Mn4(IV)O5(terpy)4(H2O)2]6+, in relation with the photosystem II oxygen-evolving center model [Mn2(III,IV)O2(terpy)2(H2O)2]3+.

To examine the real ability of the binuclear di-mu-oxo complex [Mn2(III,IV)O2(terpy)2(H2O)2]3+ (2) to act as a catalyst for water oxidation, we have investigated in detail its redox properties and that of its mononuclear precursor complex [Mn(II)(terpy)2]2+ (1) in aqueous solution. It appears that electrochemical oxidation of 1 allows the quantitative formation of 2 and, most importantly, that electrochemical oxidation of 2 quantitatively yields the stable tetranuclear Mn(IV) complex, [Mn4(IV)O5(terpy)4(H2O)2]6+ (4), having a linear mono-mu-oxo{Mn2(mu-oxo)2}2 core. Therefore, these results show that the electrochemical oxidation of 2 in aqueous solution is only a one-electron process leading to 4 via the formation of a mono-mu-oxo bridge between two oxidized [Mn2(IV,IV)O2(terpy)2(H2O)2]4+ species.

Sulfide oxidation by hydrogen peroxide catalyzed by iron complexes: two metal centers are better than one.

Peroxoiron species have been proposed to be involved in catalytic cycles of iron-dependent oxygenases and in some cases as the active intermediates during oxygen-transfer reactions. The catalytic properties of a mononuclear iron complex, [Fe(II)(pb)(2)(CH(3)CN)(2)] (pb=(-)4,5-pinene-2,2'-bipyridine), have been compared to those of its related dinuclear analogue. Each system generates specific peroxo adducts, which are responsible for the oxidation of sulfides to sulfoxides.