Conception et caractérisation d’une batterie organique obtenue par greffage direct de molécules électroactives sur carbone activé

Date du colloque : 07/2013</p

Toward fully organic rechargeable charge storage devices based on carbon electrodes grafted with redox molecules

Activated carbon powders modified with naphthalimide and 2,2,6,6-tetramethylpiperidine-N-oxyl were assembled into a hybrid electrochemical capacitor containing an organic electrolyte. The fully organic rechargeable system demonstrated an increase in specific capacitance up to 51%, an extended operating voltage of 2.9 V in propylene carbonate, compared to 1.9 V for the unmodified system, and a power 2.5 times higher

Direct introduction of redox centers at activated carbon substrate based on acid-substituent-assisted diazotization

Redox properties have been imparted to activated carbon with a high degree of functionalization by chemical grafting of 2-amino-4,5-dimethoxybenzoic add in situ diazotized. The diazotization reaction was accomplished in the presence or in the absence of HCl for estimating the positive or negative effect of the carboxylic acid substituent on the grafting yield. Thermal gravimetric analysis, X-ray photoelectron spectroscopy and cyclic voltammetry experiments show that when the carboxylic acid group participates to the diazotization reaction. the grafting yield is improved and becomes even better than when the carboxylic group is not present, increasing the capacitance of pristine carbon electrode from 120 to 200 F/g

Two-Dimensional Materials from Data Filtering and Ab Initio Calculations

Progress in materials science depends on the ability to discover new materials and to obtain and understand their properties. This has recently become particularly apparent for compounds with reduced dimensionality, which often display unexpected physical and chemical properties, making them very attractive for applications in electronics, graphene being so far the most noteworthy example. Here, we report some previously unknown two-dimensional materials and their electronic structure by data mining among crystal structures listed in the International Crystallographic Structural Database, combined with density-functional-theory calculations. As a result, we propose to explore the synthesis of a large group of two-dimensional materials, with properties suggestive of applications in nanoscale devices, and anticipate further studies of electronic and magnetic phenomena in low-dimensional systems.Peer reviewe

Greffage de molécules électroactives pour améliorer les performances des dispositifs de stockage de l’énergie électrique

Date du colloque : 07/2013</p

Spontaneous chemical modification of activated carbon powders by reduction of diazonium salts in situ generated by self-diazotization for energy storage applications

Date du colloque : 06/2011</p

Spontaneous Chemical Modification of Activated Carbon based on Diazonium Salts In Situ Generated by Self-Diazotization for Supercapacitors

Date du colloque : 08/2012</p

Chemical functionalization of activated carbon through radical and diradical intermediates

Small redox molecules were grafted on carbon through radical and diradical procedures. The reactive intermediates were derived from the 3,4-dimethoxybenzenediazonium salt and the 4,5-dimethoxybenzenediazonium-2-carboxylate salt prepared and decomposed in situ, yielding the dimethoxybenzene radical and the analogous diradical benzyne, respectively. In both cases, the activated carbon Norit serves as trapping agent and the dimethoxybenzene–carbon composites obtained were compared by thermal gravimetric analysis, X-ray photoelectron spectroscopy and cyclic voltammetry. After oxidative ether cleavage of dimethoxybenzene molecules attached to the surface, the resultant catechol-modified carbon electrodes served as pseudo-capacitive materials in aqueous electrochemical capacitors

Chemical functionalization of activated carbon based on diazonium salts in situ generated by self-diazotization. A new step toward pseudo-capacitive materials for energy storage

Date du colloque : 20-21/06/2012</p