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Sivasankaran, V., Marino, C., Chamas, M., Soudan, P., Guyomard, D., Jumas, J. C., Lippens, P. E., Monconduit, L. & Lestriez, B. (2011) Improvement of intermetallics electrochemical behavior by playing with the composite electrode formulation. J. Mater. Chem. 21 5076–5082.
Added by: Laurent Cournède (2016-03-10 21:32:21) |
| Type de référence: Article DOI: 10.1039/c0jm03831h Numéro d'identification (ISBN etc.): 0959-9428 Clé BibTeX: Sivasankaran2011 Voir tous les détails bibliographiques  |
Catégories: ST2E Mots-clés: Binder, Cathodes, cells, cellulose, Graphite anode, Li-ion batteries, performance, polyacrylate, si negative electrodes, silicon Créateurs: Chamas, Guyomard, Jumas, Lestriez, Lippens, Marino, Monconduit, Sivasankaran, Soudan Collection: J. Mater. Chem. |
Consultations : 5/439
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| Résumé |
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The impact of both various binders and carbon additives on the electrochemical behavior of intermetallics-based (FeSn(2), NiSb(2), TiSnSb) negative electrodes vs. Li was evaluated and accurately studied for FeSn(2). The formulation of the composite electrode allowed enhancement of both the capacity retention as well as the rate capability. CMC/VGCF (carboxymethyl cellulose/vapor grown carbon fiber) used as a binder/conductive additive allows retention of 100\% of the specific capacity during 35 cycles at 2C rate (2Li h(-1)), whereas the fading is dramatic after only a few cycles at a low rate with classical powdered electrodes. Notably, an extra capacity is observed with CMC/VGCF. In the case of FeSn2, it is shown that the improvement of performance achieved with CMC/VGCF results from better efficiency of the conductive additive to form an electronic percolation web around the active material (AM) particles rather than from the buffering of the volume variations of the AM particles, contrary to the case of Si-based electrodes. The improved cycle life is also likely due to the better ability of CMC to cover the particles compared to PVDF (polyvinylidene fluoride), resulting not only in stronger interparticle bonding but also in a better SEI layer. It is suggested that the growing of an insulating SEI layer by the degradation of the liquid electrolyte is an important factor in the fading mechanism of FeSn(2) composite electrodes. Finally, the aqueous processing of the FeSn(2), NiSb(2), and TiSnSb intermetallics-based composite electrodes is feasible.
Added by: Laurent Cournède |