Abstract
The electrochemical lithiation capacity of 6H silicon carbide (0001) is found to increase by over 1 order of magnitude following graphitization at 1350 °C in ultrahigh vacuum. Through several control experiments, this Li-ion capacity enhancement is correlated with SiC substrate doping and removal of the native oxide surface layer by thermal annealing, which renders both the bulk and surface electrically conductive. Characterization via multiple depth-resolved spectroscopies shows that lithium penetrates the activated SiC upon lithiation, the bulk lattice spacing does not appreciably change, and the surface structure remains largely intact. The electron energy-loss spectroscopy (EELS) extracted compositional ratio of Li to Si is approximately 1:1, which indicates an intrinsic bulk Li capacity in activated SiC of 670 mAh g -1. In addition, inelastic X-ray scattering spectra show changes in the Si chemical bonding configuration due to lithiation. X-ray scattering data show a decrease in the SiC Bragg peak intensity during lithiation, suggesting changes to the bulk crystallinity, whereas the emergence of a diffuse scattering feature suggests that lithiation is associated with the development of substrate defects. Overall, these results illustrate that the electrochemical capacity of a traditionally inert refractory material can be increased substantially via surface modification, thus suggesting a new strategy for improving the performance of next generation Li-ion battery electrodes.
| Original language | English |
|---|---|
| Pages (from-to) | 20949-20957 |
| Number of pages | 9 |
| Journal | Journal of Physical Chemistry C |
| Volume | 116 |
| Issue number | 39 |
| DOIs | |
| Publication status | Published - Oct 4 2012 |
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ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Electronic, Optical and Magnetic Materials
- Surfaces, Coatings and Films
- Energy(all)
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Enhanced lithiation of doped 6H silicon carbide (0001) via high temperature vacuum growth of epitaxial graphene. / Lipson, Albert L.; Chattopadhyay, Sudeshna; Karmel, Hunter J.; Fister, Timothy T.; Emery, Jonathan D.; Dravid, Vinayak P.; Thackeray, Michael M.; Fenter, Paul A.; Bedzyk, Michael J.; Hersam, Mark C.
In: Journal of Physical Chemistry C, Vol. 116, No. 39, 04.10.2012, p. 20949-20957.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Enhanced lithiation of doped 6H silicon carbide (0001) via high temperature vacuum growth of epitaxial graphene
AU - Lipson, Albert L.
AU - Chattopadhyay, Sudeshna
AU - Karmel, Hunter J.
AU - Fister, Timothy T.
AU - Emery, Jonathan D.
AU - Dravid, Vinayak P.
AU - Thackeray, Michael M.
AU - Fenter, Paul A.
AU - Bedzyk, Michael J.
AU - Hersam, Mark C
PY - 2012/10/4
Y1 - 2012/10/4
N2 - The electrochemical lithiation capacity of 6H silicon carbide (0001) is found to increase by over 1 order of magnitude following graphitization at 1350 °C in ultrahigh vacuum. Through several control experiments, this Li-ion capacity enhancement is correlated with SiC substrate doping and removal of the native oxide surface layer by thermal annealing, which renders both the bulk and surface electrically conductive. Characterization via multiple depth-resolved spectroscopies shows that lithium penetrates the activated SiC upon lithiation, the bulk lattice spacing does not appreciably change, and the surface structure remains largely intact. The electron energy-loss spectroscopy (EELS) extracted compositional ratio of Li to Si is approximately 1:1, which indicates an intrinsic bulk Li capacity in activated SiC of 670 mAh g -1. In addition, inelastic X-ray scattering spectra show changes in the Si chemical bonding configuration due to lithiation. X-ray scattering data show a decrease in the SiC Bragg peak intensity during lithiation, suggesting changes to the bulk crystallinity, whereas the emergence of a diffuse scattering feature suggests that lithiation is associated with the development of substrate defects. Overall, these results illustrate that the electrochemical capacity of a traditionally inert refractory material can be increased substantially via surface modification, thus suggesting a new strategy for improving the performance of next generation Li-ion battery electrodes.
AB - The electrochemical lithiation capacity of 6H silicon carbide (0001) is found to increase by over 1 order of magnitude following graphitization at 1350 °C in ultrahigh vacuum. Through several control experiments, this Li-ion capacity enhancement is correlated with SiC substrate doping and removal of the native oxide surface layer by thermal annealing, which renders both the bulk and surface electrically conductive. Characterization via multiple depth-resolved spectroscopies shows that lithium penetrates the activated SiC upon lithiation, the bulk lattice spacing does not appreciably change, and the surface structure remains largely intact. The electron energy-loss spectroscopy (EELS) extracted compositional ratio of Li to Si is approximately 1:1, which indicates an intrinsic bulk Li capacity in activated SiC of 670 mAh g -1. In addition, inelastic X-ray scattering spectra show changes in the Si chemical bonding configuration due to lithiation. X-ray scattering data show a decrease in the SiC Bragg peak intensity during lithiation, suggesting changes to the bulk crystallinity, whereas the emergence of a diffuse scattering feature suggests that lithiation is associated with the development of substrate defects. Overall, these results illustrate that the electrochemical capacity of a traditionally inert refractory material can be increased substantially via surface modification, thus suggesting a new strategy for improving the performance of next generation Li-ion battery electrodes.
UR - http://www.scopus.com/inward/record.url?scp=84865133978&partnerID=8YFLogxK
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U2 - 10.1021/jp307220y
DO - 10.1021/jp307220y
M3 - Article
AN - SCOPUS:84865133978
VL - 116
SP - 20949
EP - 20957
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 39
ER -