Operando NMR characterization of cycled and calendar aged nanoparticulate silicon anodes for Li-ion batteries
Journal Article
·
· Journal of Power Sources
- Argonne National Laboratory (ANL), Argonne, IL (United States)
Replacing graphite anodes with Si anodes can greatly increase the energy of current Li-ion batteries. Detailed characterization of Si lithiation reactions, SEI formation, and reversibility are therefore active areas of research. Solid-state 7Li nuclear magnetic resonance (NMR) spectroscopy is useful for characterizing different lithium local environments within Si anodes. Here, we developed an operando NMR methodology to characterize aging of carbon-coated nanoparticulate Si anodes in pouch cells paired with Ni-rich cathodes. We observed a new lithiation mechanism in the Si nanoparticles: direct formation of over-lithiated Li15+xSi4 (x<0.6) phase. Furthermore, our novel operando cells maintained good performance with long-term cycle and calendar aging. Here we identified trapped lithium silicides as a major contributor to capacity fade with aging. Finally, we determined that the addition of Mg (TFSI)2 to the electrolyte decreased the amount of trapped lithium silicides and therefore increased the capacity and capacity retention for the nanoparticulate Si used.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 2502013
- Alternate ID(s):
- OSTI ID: 2335934
- Journal Information:
- Journal of Power Sources, Journal Name: Journal of Power Sources Vol. 604; ISSN 0378-7753
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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