Boniface, M., Quazuguel, L., Danet, J., Guyomard, D., Moreau, P. & Bayle-Guillemaud, P. (2016) Nanoscale Chemical Evolution of Silicon Negative Electrodes Characterized by Low-Loss STEM-EELS. Nano Lett. 16 7381–7388.
Added by: Richard Baschera (2017-02-02 13:52:01) Last edited by: Richard Baschera (2017-02-02 13:52:24)
|Type de référence: Article
Numéro d'identification (ISBN etc.): 1530-6984
Clé BibTeX: Boniface2016
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Mots-clés: beam damage, chemical mapping, cycle life, energy-loss spectroscopy, fluoroethylene carbonate, interfacial properties, interphase sei, layer formation, Lithium ion battery, Lithium-ion batteries, ray photoelectron-spectroscopy, silicon anode, solid electrolyte interphase, state nmr-spectroscopy, stem-eels, surface-chemistry
Créateurs: Bayle-Guillemaud, Boniface, Danet, Guyomard, Moreau, Quazuguel
Collection: Nano Lett.
Consultations : 7/407
Indice de consultation : 3%
Indice de popularité : 0.75%
Continuous solid electrolyte interface (SEI) formation remains the limiting factor of the lifetime of silicon nanoparticles (SiNPs) based negative electrodes. Methods that could provide clear diagnosis of the electrode degradation are of utmost necessity to streamline further developments. We demonstrate that electron energy-loss spectroscopy (EELS) in a scanning transmission electron microscope (STEM can be used to quickly map SEI components and quantify LixSi alloys from single experiments with resolutions down to 5 nm. Exploiting the low-loss part of the EEL spectrum allowed us to circumvent the degradation phenomena that have so far crippled the application of this technique on such beam-sensitive compounds. Our results provide unprecedented insight into silicon aging mechanisms in full cell configuration. We observe the morphology of the SEI to be extremely heterogeneous at the particle scale but with clear chemical evolutions with extended cycling coming from both SEI accumulation and a transition from lithium-rich carbonate-like compounds to lithium-poor ones. Thanks to the retrieval of several results from a single data set we were able to correlate local discrepancies in lithiation to the initial crystallinity of silicon as well as to the local SEI chemistry and morphology. This study emphasizes how initial heterogeneities in the percolating electronic network and the porosity affect SiNPs aggregates along cycling. These findings pinpoint the crucial role of an optimized formulation in silicon-based thick electrodes.