Abstract
This work focuses on the mechanisms of interfacial processes at the surface of amorphous silicon thin-film electrodes in organic carbonate electrolytes to unveil the origins of the inherent nonpassivating behavior of silicon anodes in Li-ion batteries. Attenuated total reflection Fourier-transform infrared spectroscopy, X-ray absorption spectroscopy, and infrared near-field scanning optical microscopy were used to investigate the formation, evolution, and chemical composition of the surface layer formed on Si upon cycling. We found that the chemical composition and thickness of the solid/electrolyte interphase (SEI) layer continuously change during the charging/discharging cycles. This SEI layer "breathing"effect is directly related to the formation of lithium ethylene dicarbonate (LiEDC) and LiPF6 salt decomposition products during silicon lithiation and their subsequent disappearance upon delithiation. The detected appearance and disappearance of LiEDC and LiPF6 decomposition compounds in the SEI layer are directly linked with the observed interfacial instability and poor passivating behavior of the silicon anode.
Original language | English |
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Pages (from-to) | 40879-40890 |
Number of pages | 12 |
Journal | ACS Applied Materials and Interfaces |
Volume | 12 |
Issue number | 36 |
DOIs | |
State | Published - Sep 9 2020 |
Funding
This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract no. DE-AC02-05CH11231 under the Silicon Electrolyte Interface Stabilization (SEISta) Consortium directed by Brian Cunningham and managed by Anthony Burrell. The XAS measurements were performed at the ALS in Lawrence Berkeley National Laboratory, supported by DOE under Contract no. DE-AC02-05CH11231. A portion of this work (G.M.V.-film growth) was performed at the Oak Ridge National Laboratory, which is managed by UT Battelle LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725. This work was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy under Contract no. DE-AC02-05CH11231, under the Silicon Electrolyte Interface Stabilization (SEISta) Consortium directed by Brian Cunningham and managed by Anthony Burrell. The XAS measurements were performed at the ALS in Lawrence Berkeley National Laboratory, supported by DOE under Contract no. DE-AC02-05CH11231. A portion of this work (G.M.V.—film growth) was performed at the Oak Ridge National Laboratory, which is managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) under contract DE-AC05-00OR22725.
Keywords
- SEI breathing
- interfacial reactivity
- lithium ethylene decarbonate
- lithium-ion battery
- passivation
- silicon anode
- solid electrolyte interphase (SEI)
- thin film