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Madec, L., Humbert, B., Lestriez, B., Brousse, T., Cougnon, C., Guyomard, D. & Gaubicher, J. (2013) Covalent vs. non-covalent redox functionalization of C-LiFePO4 based electrodes. J. Power Sources, 232 246–253.
Added by: Laurent Cournède (2016-03-10 21:23:30) |
| Type de référence: Article DOI: 10.1016/j.jpowsour.2012.10.100 Numéro d'identification (ISBN etc.): 0378-7753 Clé BibTeX: Madec2013a Voir tous les détails bibliographiques  |
Catégories: ST2E Mots-clés: aryldiazonium salts, Carbon additive, carbon nanotubes, composite electrodes, Diazonium, Diazonium salts, electrochemical reduction, energy-storage, iron surfaces, LiFePO4, Lithium-ion batteries, negative-electrode, Power performance, pyrene, radicals, redox functionalization Créateurs: Brousse, Cougnon, Gaubicher, Guyomard, Humbert, Lestriez, Madec Collection: J. Power Sources |
Consultations : 8/501
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| Résumé |
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During high rate utilization of porous Li battery, Li+ refuelling from the electrolyte limits the discharge kinetics of positive electrodes. In the case of thick electrodes a strategy to buffer the resulting sharp drop of Li+ concentration gradient would be to functionalize the electrode with anionic based redox molecules (RMR) that would be therefore able to relay intercalation process. The occurrence of these RMR in the electrode should not however, induce adverse effect on Li intercalation processes. In this respect, this work studies the effect of functionalizing LFPC based electrodes by either covalent or non-covalent chemistry, on Li intercalation kinetics. To do so, model molecules containing a nitro group were introduced at the surface of both carbon conducting additives and active material (C-LiFePO4). It is shown that presumably due to formation of sp(3) defects, covalent anchoring using diazonium chemistry inhibits the intercalation kinetics in C-FePO4. On the contrary, if molecules such as pyrene derivatives are immobilized by pi-staking interactions, Li intercalation is not impeded. Therefore non-covalent functionalization of pyrene based RMR appears as a promising route to relay Li intercalation reaction during high power demand. The framework for future development of this strategy is discussed. (C) 2013 Elsevier B.V. All rights reserved.
Added by: Laurent Cournède |