Energetic evaluation of possible stacking structures of Li-intercalation in graphite using a first-principle pseudopotential calculation

Imai, Yoji; Watanabe, Akio

doi:10.1016/j.jallcom.2006.08.061

Cited by 61 publications

(49 citation statements)

References 17 publications

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“…The intercalation enthalpies of LiC 6 and LiC 12 obtained from calorimetric measurements at 455 K with respect to liquid Li, are −0.144 and −0.257 eV/Li, respectively [74]. Converting to solid Li as a reference state [75,76], these enthalpies become −0.113 and −0.226 eV/Li. Even without including vibrational and finite temperature effects (to be discussed below), the calculations give intercalation energies that are consistently more negative than those obtained experimentally [77].…”

Section: B LI Intercalationmentioning

confidence: 99%

Li intercalation in graphite: A van der Waals density-functional study

2014

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Modeling layered intercalation compounds from first principles poses a problem, as many of their properties are determined by a subtle balance between van der Waals interactions and chemical or Madelung terms, and a good description of van der Waals interactions is often lacking. Using van der Waals density functionals we study the structures, phonons and energetics of the archetype layered intercalation compound Li-graphite. Intercalation of Li in graphite leads to stable systems with calculated intercalation energies of −0.2 to −0.3 eV/Li atom, (referred to bulk graphite and Li metal). The fully loaded stage 1 and stage 2 compounds LiC 6 and Li 1/2 C 6 are stable, corresponding to two-dimensional √ 3× √ 3 lattices of Li atoms intercalated between two graphene planes. Stage N > 2 structures are unstable compared to dilute stage 2 compounds with the same concentration. At elevated temperatures dilute stage 2 compounds easily become disordered, but the structure of Li 3/16 C 6 is relatively stable, corresponding to a √ 7× √ 7 in-plane packing of Li atoms. First-principles calculations, along with a Bethe-Peierls model of finite temperature effects, allow for a microscopic description of the observed voltage profiles.

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Section: B LI Intercalationmentioning

confidence: 99%

Li intercalation in graphite: A van der Waals density-functional study

2014

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“…In a recent study, however, Li-intercalated BLG was found to take the A-A stacked form with Li atoms intercalated at the center of the hexagons in the upper and lower graphene sheets [11]. Bulky graphite Li-intercalation compound (GIC) is also known to 4 be in the A-A stacking [12,13].In this study, it is suggested, based on ex situ measurements of Shubnikov - The samples used in the present study were pristine BLG (Sample A),Li-intercalated BLG [14], and Li-desorbed BLG (Sample B). Their RHEED patterns are shown in Fig.…”

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confidence: 99%

Berry phase shift from 2π to π in bilayer graphene by Li-intercalation and sequential desorption

Akiyama

Takano

Endo

et al. 2017

Applied Physics Letters

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We have found that the Berry phase of bilayer graphene becomes p from 2p estimated by Shubnikov-de Haas oscillations when the A-B stacked pristine bilayer graphene experiences the Li-intercalation and sequential Li-desorption process in ultrahigh vacuum. Furthermore, the mobility of such processed bilayer graphene increases around four times larger, ~ 8,000 cm 2 /V·s, than that of the pristine bilayer graphene. This is mainly due to increment of the scattering time and decrement of the cyclotron mass, * akiyama@surface.phys.s.u-tokyo.ac.jp 2 which can be interpreted as a result of the change of the stacking structure of bilayer graphene from A-B to A-A, corresponding to a change from the parabolic to the linear band dispersion. 3Monolayer graphene is well known to be a two-dimensional (2D) [5][6][7]. This difference between the A-B and A-A stacked BLGs, of course, causes some difference in their physical and electronic properties. Especially, the Berry phase is different between the two systems; that of Dirac system is π, while that of Schrödinger system is 2π.In spite of these remarkable characteristics of BLG, the method of fabricating the A-A stacked BLG has not been reported yet except for the local observation [8,9]. This is because the A-B stacking is energetically more favorable than the A-A stacking [10]. In a recent study, however, Li-intercalated BLG was found to take the A-A stacked form with Li atoms intercalated at the center of the hexagons in the upper and lower graphene sheets [11]. Bulky graphite Li-intercalation compound (GIC) is also known to 4 be in the A-A stacking [12,13].In this study, it is suggested, based on ex situ measurements of Shubnikov - The samples used in the present study were pristine BLG (Sample A),Li-intercalated BLG [14], and Li-desorbed BLG (Sample B). Their RHEED patterns are shown in Fig. 1 (a) -(c), respectively. Sample A was prepared on a n-type Si-rich 6H-SiC (0001) substrate by heating up to 1550°C in UHV (3 × 10 -10 Torr). Because the heating temperature and the keeping time were optimized, we have successfully fabricated exclusively BLG. As seen in Fig. 1(a), Sample A showed both the graphene 1×1 pattern (indicated by red arrows) and the buffer layer 6√3×6√3 R30° pattern (indicated by blue arrows). For preparing Sample B, Li was first deposited on the BLG using a Li dispenser (SAES Getters) at room temperature in UHV. This Li-intercalated BLG sample showed a RHEED pattern of √3×√3 R30° (indicated by yellow arrows) as shown in Fig. 1(b) [14,10,15]. Such a RHEED pattern reflects Li atoms arranged regularly in the interlayer space. Here, the green arrows show the SiC substrate 1×1 5 pattern. Then, it was heated up at 900°C to desorb Li atoms until the √3×√3 R30° pattern disappeared and the 6√3×6√3 R30° pattern from the buffer layer revived as shown in Fig. 1(c). This is Sample B.The samples were taken out from the UHV chamber, and bonded to Au wires with Indium to form the conventional 6-terminal methods. All electrical transport measurements were performed w...

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“…The calculation methods are the same as those used in previous studies on the electronic energy calculations of anode materials for rechargeable Li-ion batteries, Li-graphite [6] and Li-La 3 Ni 2 Sn 7 [7]. That is, calculations have been performed using CASTEP (Cambridge Serial Total Energy Package) developed by Payne et al [8].…”

Section: Calculation Methodsmentioning

confidence: 99%