Functionalized carbon nanotubes fir Lithium-Sulphur and Lithium-Organic batteries
Résumé
Lithium batteries are among the most promising systems for electrochemical energy storage. However, their capacity and cost-efficiency have to be improved for further applications, for instance in electric vehicles. Lithium/organic and lithium/sulfur batteries offer an interesting alternative to the classical Li-ion systems due to their high theoretical specific capacity and potential low cost. However, two major roadblocks currently prevent industrial development of these kind batteries: (i) the progressive dissolution of active material in the electrolyte, which hinders cyclability of the devices and; (ii) the electrical insulating nature of organic or sulfur materials. Here, we develop a new positive electrode material avoiding the dissolution of the active material in the electrolyte upon cycling, by grafting new diazonium derivatives containing active disulfide groups onto multi-walled carbon nanotubes (MWNTs). The MWNTs insure a well distributed electronic conductivity inside the positive electrode and serve as a support for a covalent immobilization of the thiolated active species. Compared to electrodes formed by simply mixing carbon nanotubes with thiol-containing molecules, covalently functionalized MWNT materials present an excellent stability over prolonged cycling and a promising specific capacity, in the range of 100 mAh·g$_{electrode}^{-1}$ , i.e. including carbon and current collector masses.
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)