Silicon Solid Electrolyte Interphase (SEI) of Lithium Ion Battery Characterized by Microscopy and Spectroscopy
- University of Rhode Island, Kingston, Rhode Island 02881, United States
- Argonne National Laboratory, Argonne, Illinois 60439, United States
The surface reactions of electrolytes with a silicon anode in lithium ion cells have been investigated. The investigation utilizes two novel techniques that are enabled by the use of binder-free silicon (BF-Si) nanoparticle anodes. The first method, transmission electron microscopy with energy dispersive X-ray spectroscopy, allows straightforward analysis of the BF-Si solid electrolyte interphase (SEI). The second method utilizes multi-nuclear magnetic resonance spectroscopy of D2O extracts from the cycled anodes. The TEM and NMR data are complemented by XPS and FTIR data, which are routinely used for SEI studies. Coin cells (BF-Si/Li) were cycled in electrolytes containing LiPF6 salt and ethylene carbonate or fluoroethylene carbonate solvent. Capacity retention was significantly better for cells cycled with LiPF6/FEC electrolyte than for cells cycled with LiPF6/EC electrolyte. Our unique combination of techniques establishes that for LiPF6/EC electrolyte the BF-Si SEI continuously grows during the first 20 cycles and the SEI becomes integrated with the BF-Si nanoparticles. The SEI predominantly contains lithium ethylene dicarbonate, LiF, and LixSiOy. BF-Si electrodes cycled with LiPF6/FEC electrolyte have a different behavior; the BF-Si nanoparticles remain relatively distinct from the SEI. The SEI predominantly contains LiF, LixSiOy, and an insoluble polymeric species.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE) - Office of Vehicle Technology; USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1392670
- Journal Information:
- Journal of Physical Chemistry. C, Vol. 117, Issue 26; ISSN 1932-7447
- Publisher:
- American Chemical Society
- Country of Publication:
- United States
- Language:
- English
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