Abstract
Fluoroethylene carbonate (FEC) as an electrolyte additive can considerably improve the cycling performance of silicon (Si) electrodes in Li-ion batteries. However, the fundamental mechanism for how FEC contributes to solid electrolyte interphase (SEI) morphological changes and chemical composition is not well understood. Here, scanning transmission electron microscopy coupled with electron energy loss spectroscopy gives a comprehensive insight as to how FEC affects the SEI evolution in terms of composition and morphology throughout electrochemical cycling. In the first lithiation cycle, the electrode cycled in ethylene carbonate (EC): diethylene carbonate (DEC) forms a porous uneven SEI composed of mostly Li2CO3. However, the electrode cycled in EC/DEC/FEC is covered in a dense and uniform SEI containing mostly LiF. Interestingly, the intrinsic oxide layer (Li x SiO y) is not observed at the interface of electrode cycled in EC/DEC/FEC after 1 cycle. This is consistent with fluoride anion formation from the reduction of FEC, which leads to the chemical attack of any silicon-oxide surface passivation layer. Furthermore, surface sensitive helium ion microscopy and X-ray photoelectron spectroscopy techniques give further insights to the SEI composition and morphology in both electrodes cycled with different electrolytes.
| Original language | English |
|---|---|
| Article number | 1600438 |
| Journal | Advanced Materials Interfaces |
| Volume | 3 |
| Issue number | 20 |
| DOIs | |
| Publication status | Published - Oct 19 2016 |
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Keywords
- electron energy loss spectroscopy
- fluoroethylene carbonate
- scanning transmission electron microscopy
- solid electrolyte interphases
ASJC Scopus subject areas
- Mechanics of Materials
- Mechanical Engineering
Cite this
Direct Visualization of the Solid Electrolyte Interphase and Its Effects on Silicon Electrochemical Performance. / Sina, Mahsa; Alvarado, Judith; Shobukawa, Hitoshi; Alexander, Caleb; Manichev, Viacheslav; Feldman, Leonard C; Gustafsson, Torgny; Stevenson, Keith J.; Meng, Ying Shirley.
In: Advanced Materials Interfaces, Vol. 3, No. 20, 1600438, 19.10.2016.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Direct Visualization of the Solid Electrolyte Interphase and Its Effects on Silicon Electrochemical Performance
AU - Sina, Mahsa
AU - Alvarado, Judith
AU - Shobukawa, Hitoshi
AU - Alexander, Caleb
AU - Manichev, Viacheslav
AU - Feldman, Leonard C
AU - Gustafsson, Torgny
AU - Stevenson, Keith J.
AU - Meng, Ying Shirley
PY - 2016/10/19
Y1 - 2016/10/19
N2 - Fluoroethylene carbonate (FEC) as an electrolyte additive can considerably improve the cycling performance of silicon (Si) electrodes in Li-ion batteries. However, the fundamental mechanism for how FEC contributes to solid electrolyte interphase (SEI) morphological changes and chemical composition is not well understood. Here, scanning transmission electron microscopy coupled with electron energy loss spectroscopy gives a comprehensive insight as to how FEC affects the SEI evolution in terms of composition and morphology throughout electrochemical cycling. In the first lithiation cycle, the electrode cycled in ethylene carbonate (EC): diethylene carbonate (DEC) forms a porous uneven SEI composed of mostly Li2CO3. However, the electrode cycled in EC/DEC/FEC is covered in a dense and uniform SEI containing mostly LiF. Interestingly, the intrinsic oxide layer (Li x SiO y) is not observed at the interface of electrode cycled in EC/DEC/FEC after 1 cycle. This is consistent with fluoride anion formation from the reduction of FEC, which leads to the chemical attack of any silicon-oxide surface passivation layer. Furthermore, surface sensitive helium ion microscopy and X-ray photoelectron spectroscopy techniques give further insights to the SEI composition and morphology in both electrodes cycled with different electrolytes.
AB - Fluoroethylene carbonate (FEC) as an electrolyte additive can considerably improve the cycling performance of silicon (Si) electrodes in Li-ion batteries. However, the fundamental mechanism for how FEC contributes to solid electrolyte interphase (SEI) morphological changes and chemical composition is not well understood. Here, scanning transmission electron microscopy coupled with electron energy loss spectroscopy gives a comprehensive insight as to how FEC affects the SEI evolution in terms of composition and morphology throughout electrochemical cycling. In the first lithiation cycle, the electrode cycled in ethylene carbonate (EC): diethylene carbonate (DEC) forms a porous uneven SEI composed of mostly Li2CO3. However, the electrode cycled in EC/DEC/FEC is covered in a dense and uniform SEI containing mostly LiF. Interestingly, the intrinsic oxide layer (Li x SiO y) is not observed at the interface of electrode cycled in EC/DEC/FEC after 1 cycle. This is consistent with fluoride anion formation from the reduction of FEC, which leads to the chemical attack of any silicon-oxide surface passivation layer. Furthermore, surface sensitive helium ion microscopy and X-ray photoelectron spectroscopy techniques give further insights to the SEI composition and morphology in both electrodes cycled with different electrolytes.
KW - electron energy loss spectroscopy
KW - fluoroethylene carbonate
KW - scanning transmission electron microscopy
KW - solid electrolyte interphases
UR - http://www.scopus.com/inward/record.url?scp=84991666784&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84991666784&partnerID=8YFLogxK
U2 - 10.1002/admi.201600438
DO - 10.1002/admi.201600438
M3 - Article
VL - 3
JO - Advanced Materials Interfaces
JF - Advanced Materials Interfaces
SN - 2196-7350
IS - 20
M1 - 1600438
ER -