Lithium Adsorption on Graphene: From Isolated Adatoms to Metallic Sheets

Garay-Tapia, A.M.; Romero, Aldo H.; Barone, Verónica

doi:10.1021/ct300042p

Cited by 80 publications

(64 citation statements)

References 49 publications

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“…Important examples include atoms such as H, F, and O adsorbed on graphene to provide a suitable band gap for transistor applications. [3][4][5][6][7] Moreover, atoms adsorbed on 2D materials are potentially useful for ion batteries, 8 hydrogen storage materials, 9 and superconductors. 10 The physical and chemical properties of a material depend on its specific structure.…”

Section: Introductionmentioning

confidence: 99%

Structure Prediction of Atoms Adsorbed on Two-Dimensional Layer Materials: Method and Applications

Gao

Shao

et al. 2015

J. Phys. Chem. C

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The adsorption of atoms is one of the efficient approaches for functionalizing twodimensional (2D) layer materials with desirable properties. The structural knowledge of atoms adsorbed on 2D layer materials is crucial for understanding their functional performance. Here we propose a versatile method for predicting the structures of atoms adsorbed on 2D materials via the swarm-intelligence-based CALYPSO structure-prediction method. Several techniques are implemented to improve the efficiency of structure searching, including fixed adsorption sites, constraints of symmetry and distance during structure generation, and the constrained particle swarm-optimization algorithm for structure evolution. The method is successfully applied to investigate the well-studied systems of hydrogenated and oxidized graphene. The energetically most stable structures of single-sided hydrogenated graphene are predicted for different contents of hydrogen; altering the hydrogen content appears to effectively tune the band gap. An energetically most stable phase of fully oxidized graphene is also uncovered. These results provide new structural knowledge on the adsorption of atoms on graphene.

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Section: Introductionmentioning

confidence: 99%

Structure Prediction of Atoms Adsorbed on Two-Dimensional Layer Materials: Method and Applications

Gao

Shao

et al. 2015

J. Phys. Chem. C

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“…[15][16][17] In particular, several theoretical studies show that Li ions are not likely to interact strongly with the basal plane of defect-free graphene and that chemisorption is only possible at defect sites. [18][19][20][21] Studies of lithium interaction and diffusion on graphene with topological defects such as Stone-Wales (SW), double vacancies (DV), and single vacancies (SV) 16,17,22 suggest attractive Li interaction with the vacancies, possibly enhancing Li adsorption. 16 Additionally, graphene functionalization with F, O, and H species have been of high interest.…”

Section: Introductionmentioning

confidence: 99%

Defect Evolution in Graphene upon Electrochemical Lithiation

Jaber-Ansari

Puntambekar

Tavassol

et al. 2014

ACS Appl. Mater. Interfaces

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Despite rapidly growing interest in the application of graphene in lithium ion batteries, the interaction of the graphene with lithium ions and electrolyte species during electrochemical cycling is not fully understood. In this work, we use Raman spectroscopy in a model system of monolayer graphene transferred on a Si(111) substrate and density functional theory (DFT) to investigate defect formation as a function of lithiation. This model system enables the early stages of defect formation to be probed in a manner previously not possible with commonly used reduced graphene oxide or multilayer graphene substrates. Using ex situ and Ar-atmosphere Raman spectroscopy, we detected a rapid increase in graphene defect level for small increments in the number of lithiation/delithiation cycles until the I(D)/I(G) ratio reaches ∼1.5-2.0 and the 2D peak intensity drops by ∼50%, after which the Raman spectra show minimal changes upon further cycling. Using DFT, the interplay between graphene topological defects and chemical functionalization is explored, thus providing insight into the experimental results. In particular, the DFT results show that defects can act as active sites for species that are present in the electrochemical environment such as Li, O, and F. Furthermore, chemical functionalization with these species lowers subsequent defect formation energies, thus accelerating graphene degradation upon cycling. This positive feedback loop continues until the defect concentration reaches a level where lithium diffusion through the graphene can occur in a relatively unimpeded manner, with minimal further degradation upon extended cycling. Overall, this study provides mechanistic insight into graphene defect formation during lithiation, thus informing ongoing efforts to employ graphene in lithium ion battery technology.

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“…Taken from Ref. 245 Simulation studies in the area can be largely divided into two sets, MD simulations of electrolytes at graphene (see Section 'Simulations of Electrolytes at Graphene Interfaces'), and DFT calculations investigating the adsorption of the Li + to the graphene electrodes [247][248][249][250][251][252][253][254][255][256][257][258][259] which are discussed below. The maximum Li capacity of graphite is 372 mA h/g, where Li + atoms are adsorbed as LiC 6 in a ( √ 3× √ 3)R30 • structure, with the Li + atoms located in the hollow sites.…”

Section: Lithium/alkali Metal Batteriesmentioning

confidence: 99%

“…244,246,247 Some initial theoretical studies predicted that a sheet of graphene was able to exceed the maximum theoretical capacity of graphite due to the adsorption of Li atoms to both surfaces of the sheet, allowing a higher Li/C ratio than 1:6. 246,250,252,254 In particular, it has been predicted that a Li 2 C 2 structure was theoretically stable, 250,251 with one Li ion adsorbing atop a carbon atom and another Li ion adsorbing above the C atom on the opposite side of the sheet, with the result of the graphene sheet buckling and forming a structure similar to that of graphane. However, more recent theoretical studies 247,260,261 (supported by Raman spectra that show that the intercalation of Li in few-layer graphene resembles that of graphite 262 ) have suggested that that pristine graphene systems may have a theoretical Li + capacity that is lower than that of graphite.…”

Section: Lithium/alkali Metal Batteriesmentioning

confidence: 99%

Computational chemistry for graphene-based energy applications: progress and challenges

Hughes

Walsh

2015

Nanoscale

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Citation: Hughes ZE and Walsh TR (2015) Computational chemistry for graphene-based energy applications: progress and challenges. Nanoscale. 7: 6883-6908. Research in graphene-based energy materials is a rapidly growing area. Many graphene-based energy applications involve interfacial processes. To enable advances in the design of these energy materials, such that their operation, economy, efficiency and durability is at least comparable with fossil-fuel based alternatives, connections between the molecular-scale structure and function of these interfaces are needed. While it is experimentally challenging to resolve this interfacial structure, molecular simulation and computational chemistry can help bridge these gaps. In this Review, we summarise recent progress in the application of computational chemistry to graphene-based materials for fuel cells, batteries and photovoltaics. We also outline both the bright prospects and emerging challenges these techniques face for application to graphene-based energy materials in future.

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Lithium Adsorption on Graphene: From Isolated Adatoms to Metallic Sheets

Cited by 80 publications

References 49 publications

Structure Prediction of Atoms Adsorbed on Two-Dimensional Layer Materials: Method and Applications

Structure Prediction of Atoms Adsorbed on Two-Dimensional Layer Materials: Method and Applications

Defect Evolution in Graphene upon Electrochemical Lithiation

Computational chemistry for graphene-based energy applications: progress and challenges

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