Origin of low sodium capacity in graphite and generally weak substrate binding of Na and Mg among alkali and alkaline earth metals
Abstract
It is well known that graphite has a low capacity for Na but a high capacity for other alkali metals. The growing interest in alternative cation batteries beyond Li makes it particularly important to elucidate the origin of this behavior, which is not well understood. In examining this question, we find a quite general phenomenon: among the alkali and alkaline earth metals, Na and Mg generally have the weakest chemical binding to a given substrate, compared with the other elements in the same column of the periodic table. We demonstrate this with quantum mechanics calculations for a wide range of substrate materials (not limited to C) covering a variety of structures and chemical compositions. The phenomenon arises from the competition between trends in the ionization energy and the ion–substrate coupling, down the columns of the periodic table. Consequently, the cathodic voltage for Na and Mg is expected to be lower than those for other metals in the same column. This generality provides a basis for analyzing the binding of alkali and alkaline earth metal atoms over a broad range of systems.
Additional Information
© 2016 National Academy of Sciences. Contributed by William A. Goddard III, February 19, 2016 (sent for review January 25, 2016; reviewed by Yi Cui and Michael L. Klein). Published online before print March 21, 2016. Y.L. thanks Drs. Brandon Wood, Suhuai Wei, and Jiayu Wan for helpful discussions and Brandon Wood for providing access to the Lawrence Livermore National Laboratory computational resources, which were used for some of the computations (supported under the Laboratory Directed Research and Development Program). Most of the calculations were performed on National Energy Research Scientific Computing Center, a Department of Energy (DOE) Office of Science User Facility supported by the Office of Science of the US DOE under Contract DE-AC02-05CH11231. Y.L. acknowledges the support from Resnick Prize Postdoctoral Fellowship at Caltech. This research was funded by the Bosch Energy Research Network and by NSF (CBET 1512759). Reviewers: Y.C., Stanford University; and M.L.K., Temple University. The authors declare no conflict of interest. This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1602473113/-/DCSupplemental.Attached Files
Published - PNAS-2016-Liu-3735-9.pdf
Submitted - 1604.03602.pdf
Supplemental Material - pnas.201602473SI.pdf
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Additional details
- PMCID
- PMC4833228
- Eprint ID
- 65618
- Resolver ID
- CaltechAUTHORS:20160323-103905765
- Department of Energy (DOE)
- DE-AC02-05CH11231
- Resnick Sustainability Institute
- NSF
- CBET-1512759
- Bosch Energy Research Network
- Created
-
2016-03-25Created from EPrint's datestamp field
- Updated
-
2023-06-07Created from EPrint's last_modified field
- Caltech groups
- Resnick Sustainability Institute
- Other Numbering System Name
- WAG
- Other Numbering System Identifier
- 1158