Ergué-Gabéric, France
Ergué-Gabéric, France

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Perricone E.,Grenoble Institute of Technology | Chamas M.,Grenoble Institute of Technology | Lepretre J.-C.,Grenoble Institute of Technology | Judeinstein P.,University Paris - Sud | And 7 more authors.
Journal of Power Sources | Year: 2013

This paper details the influence of adding ester co-solvent to ethylene carbonate (EC) based electrolyte in the view of supercapacitor applications. The incorporation of ester solvents with methoxy or fluorinated groups allows a good compromise to be reached between electrochemical performance in a wide temperature range and safety issue. The use of spiro-(1,1′)- bipyrrolidinium tetrafluoroborate (SBPBF4) instead of tetraethylammonium tetrafluoroborate (TEABF4) allows the increase of electrolyte conductivity at low temperature thanks to its higher solubility. An improvement of capacitance stability is also obtained with the use of SBPBF 4. © 2013 Elsevier B.V. All rights reserved.


Perricone E.,Grenoble Institute of Technology | Chamas M.,Grenoble Institute of Technology | Cointeaux L.,Grenoble Institute of Technology | Lepretre J.-C.,Grenoble Institute of Technology | And 6 more authors.
Electrochimica Acta | Year: 2013

The performances obtained with methoxypropionitrile/ethylene carbonate mixture based electrolytes were investigated in supercapacitor application. The incorporation of methoxypropionitrile allows a good compromise between electrochemical performances and safety issue to be exhibited in a wide temperature range. This improvement is associated with the decrease of electrolyte viscosity without compromising the salt solubility and dissociation. The highest conductivity values, 20 mS cm-1 at 30°C compared to 14 mS cm-1 in PC (propylene carbonate), were obtained with both 1 M tetraethylammonium tetrafluoroborate (TEABF4) and spiro-(1,1′)-bipyrrolidium tetrafluoroborate (SBPBF4) salts. Bulk liquid state was conserved for these electrolytes in a wide temperature range. Then, interesting electrolyte conductivities were obtained at low temperature (5.2 mS cm-1 at -25°C) which is twice that of PC + TEABF4 1 M electrolyte at the same conditions. Moreover, the capacitor performance of EC/MP based electrolyte is better than PC one at room temperature. © 2013 Elsevier Ltd. © 2013 Elsevier Ltd. All rights reserved.


Deschamps M.,French National Center for Scientific Research | Deschamps M.,University of Orléans | Gilbert E.,French National Center for Scientific Research | Azais P.,Batscap | And 8 more authors.
Nature Materials | Year: 2013

Supercapacitors are electrochemical energy-storage devices that exploit the electrostatic interaction between high-surface-area nanoporous electrodes and electrolyte ions. Insight into the molecular mechanisms at work inside supercapacitor carbon electrodes is obtained with 13 C and 11 B ex situ magic-angle spinning nuclear magnetic resonance (MAS-NMR). In activated carbons soaked with an electrolyte solution, two distinct adsorption sites are detected by NMR, both undergoing chemical exchange with the free electrolyte molecules. On charging, anions are substituted by cations in the negative carbon electrode and cations by anions in the positive electrode, and their proportions in each electrode are quantified by NMR. Moreover, acetonitrile molecules are expelled from the adsorption sites at the negative electrode alone. Two nanoporous carbon materials were tested, with different nanotexture orders (using Raman and 13 C MAS-NMR spectroscopies), and the more disordered carbon shows a better capacitance and a better tolerance to high voltages. © 2013 Macmillan Publishers Limited. All rights reserved.


Lecuyer M.,Batscap | Lecuyer M.,Jean Rouxel Institute | Gaubicher J.,Jean Rouxel Institute | Deschamps M.,Batscap | And 3 more authors.
Journal of Power Sources | Year: 2013

Lithium/sulfur batteries in Lithium Metal Polymer (LMP) technology suffer from poor reversibility and important capacity fade. In this paper we studied structural evolutions of Li/S cells with PEO-based (poly(ethylene oxide)) dry polymer electrolyte, by means of scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Discharge occurs along with dissolution of the active material into soluble polysulfides in PEO. Diffusion of the sulfide species results in important volume changes of both the electrode and the electrolyte. This eventually leads to collapse of the electrode upon a few cycles, which contributes to the poor cyclability of the battery. In order to prevent this phenomenon, the mechanical strength of the cathode was enhanced by adding poly(vinylidene fluoride) (PVDF) in its composition. However, although PVDF helps maintaining the electrode's structure, it could not completely solve the cyclability issue. © 2013 Elsevier B.V. All rights reserved.


Iwama E.,CNRS Inter-university Material Research and Engineering | Iwama E.,CNRS RS2E | Taberna P.L.,CNRS Inter-university Material Research and Engineering | Taberna P.L.,CNRS RS2E | And 4 more authors.
Journal of Power Sources | Year: 2012

Electrochemical characterizations at low temperature and floating tests have been performed on 600F commercial supercapacitor (SC) for acetonitrile (AN)-based and AN + methyl acetate (MA) mixed electrolytes. From -40 to +20 °C, AN electrolyte showed slightly higher capacitance than those of AN + MA mixed electrolytes (25 and 33 vol.% of MA). At -55 °C, however, AN electrolyte did not cycle at all, while MA mixed electrolyte normally cycled with a slight decrease in their capacitance. From electrochemical impedance spectroscopy measurements, the whole resistance for AN-based cells at -55 °C was found to be about 10,000 times higher than that of +20 °C, while a 40-fold increase in the cell resistance was obtained for the MA mixture between 20 and -55 °C. From the results of floating tests at 2.7 V and 60 °C for 1 month, the 25 vol.% MA mixture showed no change and slight decreased but stable capacitance. © 2012 Elsevier B.V. All rights reserved.


Deschamps M.,French National Center for Scientific Research | Deschamps M.,University of Orléans | Cadars S.,French National Center for Scientific Research | Cadars S.,University of Orléans | And 9 more authors.
Solid State Nuclear Magnetic Resonance | Year: 2012

We show that natural abundance, solid-state MAS-NMR 13C INADEQUATE spectra can be recorded for crystallized C 70, using the through-bond J-coupling for the magnetization transfer. The effect of strong J-coupling can be lessened at high magnetic fields, allowing the observation of cross-peaks between close resonances. DFT calculations of the chemical shifts show an excellent agreement with the experimental values. A correlation is observed between the average CCC bond angles and the 13C chemical shift, offering a way to understand the dispersion of 13C chemical shifts in nanoporous activated carbons in terms of local deviations from planarity. © 2012 Elsevier Inc.


Patent
Batscap | Date: 2013-03-29

The invention relates to a bilayer polymer electrolyte for a lithium battery. The electrolyte comprises the layers N and P, each composed of a solid solution of an Li salt in a polymer material, the Li salt being the same in both layers, the polymer material content being at least 60% by weight, and the lithium salt content being from 5 to 25% by weight. The polymer material of the layer P contains a solvating polymer and a nonsolvating polymer, the weight ratio of the two polymers being such that the solvating polymer forms a continuous network. The polymer material of the layer N is composed of a solvating polymer and optionally a nonsolvating polymer, the weight ratio of the two polymers being such that the solvating polymer forms a continuous network, and the nonsolvating polymer does not form a continuous network.


Patent
French National Center for Scientific Research and Batscap | Date: 2013-04-05

The invention relates to a lithium vanadium oxide which corresponds to the formula Li_(1+)V_(3)O_(8 )(0.10.25). It is composed of agglomerates of small needles having a length l from 400 to 1000 nm, a width w such that 10


The invention relates to a lithium battery, the operation of which is security-protected by the interposition of resilient films. The battery is made up of a battery cell PEN, which comprises a film of an electrolyte E containing a lithium salt between a film P forming a positive electrode and a film N forming a negative electrode, or made up of a stack of battery cells PEN, said stack comprising two terminal battery cells between which are optionally placed one or more intermediate battery cells, said battery being characterized in that it comprises at least two protective films Fp made of a resilient material, at least one of the electrodes of the battery cell or of each terminal battery cell being in contact with a protective film Fp made of a resilient material. In particular, at least two protective films Fp are made of a resilient material having an elongation at break denoted by a_(me )and a thickness denoted by e_(me), at least one of said protective films Fp in contact with a connection layer, for connecting an electrode, having a thickness e_(max), said film having a thickness e_(me )such that e_(me)>e_(max)/a_(me). The invention relates to lithium batteries, the negative electrode of which is made of lithium metal, and to lithium ion batteries, the negative electrode of which comprises a lithium-ion insertion material.


Patent
Batscap and French National Center for Scientific Research | Date: 2010-10-19

The invention relates to the preparation of an optionally carbonaceous -LiV_(2)O_(5 )material. The process consists in preparing a composition formed of carbon and of precursors of Li and of V and in subjecting it to a heat treatment. The composition is prepared by bringing carbon, -V_(2)O_(5 )and a Li precursor into contact in amounts such that the ratio of the [V_(2)O_(5)]/[Li] concentrations is between 0.95 and 1.05 and the carbon is in excess of at least 25% with respect to the stoichiometry. The heat treatment is carried out in two stages: a first stage at a temperature between 90 C. and 150 C. for a time of 1 to 12 hours and a second stage at a temperature between 420 C. and 500 C. for a time of between 10 min and 1 hour, under a nitrogen or argon atmosphere or under vacuum.

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