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Lithium ion storage between graphenes.

Chan Y, Hill JM - Nanoscale Res Lett (2011)

Bottom Line: The number densities of lithium ions between the two graphenes are estimated from existing semi-empirical molecular orbital calculations, and the graphene sheets giving rise to the triple ion layers admit the largest storage capacity at all temperatures, followed by a marginal decrease of storage capacity for the case of double ion layers.These two configurations exceed the maximum theoretical storage capacity of graphite.Although the single ion layer provides the least charge storage, it turns out to be the most stable configuration at all temperatures.

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Affiliation: Nanomechanics Group, School of Mathematical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia. yue.chan@adelaide.edu.au.

ABSTRACT
In this article, we investigate the storage of lithium ions between two parallel graphene sheets using the continuous approximation and the 6-12 Lennard-Jones potential. The continuous approximation assumes that the carbon atoms can be replaced by a uniform distribution across the surface of the graphene sheets so that the total interaction potential can be approximated by performing surface integrations. The number of ion layers determines the major storage characteristics of the battery, and our results show three distinct ionic configurations, namely single, double, and triple ion forming layers between graphenes. The number densities of lithium ions between the two graphenes are estimated from existing semi-empirical molecular orbital calculations, and the graphene sheets giving rise to the triple ion layers admit the largest storage capacity at all temperatures, followed by a marginal decrease of storage capacity for the case of double ion layers. These two configurations exceed the maximum theoretical storage capacity of graphite. Further, on taking into account the charge-discharge property, the double ion layers are the most preferable choice for enhanced lithium storage. Although the single ion layer provides the least charge storage, it turns out to be the most stable configuration at all temperatures. One application of the present study is for the design of future high energy density alkali batteries using graphene sheets as anodes for which an analytical formulation might greatly facilitate rapid computational results.

No MeSH data available.


Related in: MedlinePlus

Total energy for lithium ion stored between two parallel graphene sheets with D = 7.7 Å.
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Figure 3: Total energy for lithium ion stored between two parallel graphene sheets with D = 7.7 Å.

Mentions: In this section, we obtain some numerical results according to the formulae given in "Theory" section. Three separation distances, namely, D = 5, 7.7, and 8.3 Å are investigated due to the fact that they allow a single layer, a double layer, and a triple layer of lithium ions embedded between two parallel graphenes, respectively [8]. The total energy for a lithium ion embedded between two graphene sheets is determined from Equation (3) and the numerical values for E for the prescribed values of D are shown in Figures 2, 3, 4 and 5. The numerical values of the parameters A, B, and eta are given in Table 1.


Lithium ion storage between graphenes.

Chan Y, Hill JM - Nanoscale Res Lett (2011)

Total energy for lithium ion stored between two parallel graphene sheets with D = 7.7 Å.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211259&req=5

Figure 3: Total energy for lithium ion stored between two parallel graphene sheets with D = 7.7 Å.
Mentions: In this section, we obtain some numerical results according to the formulae given in "Theory" section. Three separation distances, namely, D = 5, 7.7, and 8.3 Å are investigated due to the fact that they allow a single layer, a double layer, and a triple layer of lithium ions embedded between two parallel graphenes, respectively [8]. The total energy for a lithium ion embedded between two graphene sheets is determined from Equation (3) and the numerical values for E for the prescribed values of D are shown in Figures 2, 3, 4 and 5. The numerical values of the parameters A, B, and eta are given in Table 1.

Bottom Line: The number densities of lithium ions between the two graphenes are estimated from existing semi-empirical molecular orbital calculations, and the graphene sheets giving rise to the triple ion layers admit the largest storage capacity at all temperatures, followed by a marginal decrease of storage capacity for the case of double ion layers.These two configurations exceed the maximum theoretical storage capacity of graphite.Although the single ion layer provides the least charge storage, it turns out to be the most stable configuration at all temperatures.

View Article: PubMed Central - HTML - PubMed

Affiliation: Nanomechanics Group, School of Mathematical Sciences, The University of Adelaide, Adelaide, SA 5005, Australia. yue.chan@adelaide.edu.au.

ABSTRACT
In this article, we investigate the storage of lithium ions between two parallel graphene sheets using the continuous approximation and the 6-12 Lennard-Jones potential. The continuous approximation assumes that the carbon atoms can be replaced by a uniform distribution across the surface of the graphene sheets so that the total interaction potential can be approximated by performing surface integrations. The number of ion layers determines the major storage characteristics of the battery, and our results show three distinct ionic configurations, namely single, double, and triple ion forming layers between graphenes. The number densities of lithium ions between the two graphenes are estimated from existing semi-empirical molecular orbital calculations, and the graphene sheets giving rise to the triple ion layers admit the largest storage capacity at all temperatures, followed by a marginal decrease of storage capacity for the case of double ion layers. These two configurations exceed the maximum theoretical storage capacity of graphite. Further, on taking into account the charge-discharge property, the double ion layers are the most preferable choice for enhanced lithium storage. Although the single ion layer provides the least charge storage, it turns out to be the most stable configuration at all temperatures. One application of the present study is for the design of future high energy density alkali batteries using graphene sheets as anodes for which an analytical formulation might greatly facilitate rapid computational results.

No MeSH data available.


Related in: MedlinePlus