X-ray photoelectron spectroscopy analyses of lithium intercalation and alloying reactions on graphite electrodes

Momose, Hideto; Honbo, Hidetoshi; Takeuchi, Seiji; Nishimura, Kinya; Horiba, Tatsuo; Muranaka, Yasushi; Kozono, Y.; Miyadera, Hiroshi

doi:10.1016/s0378-7753(96)02627-4

Cited by 82 publications

(35 citation statements)

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“…4,5 This evolved into an elegant theory of alkali-intercalated graphite interlayer states as interacting nonorthogonal hybrid states of Li 2s and graphite interlayer states. 6,7 This gives credence to x-ray photoelectron spectroscopy ͑XPS͒ results by Momose et al 8 and others 9 claiming Li to be intercalated into graphite as ionic Li ϩ . Early experimental work by Grunes et al 10 using electron energy-loss spectroscopy ͑EELS͒ demonstrated distortions of the graphite band structure upon intercalation of alkali metals.…”

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confidence: 60%

“…Extensive XPS results confirm a Li K edge chemical shift of about 3 eV in LiC 6 with respect to metallic Li, 8,9 easily resolved from the 1.3 eV chemical shift of Li 2 O. 23 The mean free path of photoelectrons measured by XPS is on the order of 1 nm.…”

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confidence: 81%

“…Early experimental work by Grunes et al 10 using electron energy-loss spectroscopy ͑EELS͒ demonstrated distortions of the graphite band structure upon intercalation of alkali metals. Hartwigsen et al 11 used a density functional theory, local density approximation to determine the degree of charge transfer from Li to the intercalant host lattice to be 0.5e for LiC 6 and 0.4e for LiC 8 . Further experiments using inelastic x-ray scattering spectroscopy by Schülke 12 were able to correlate features of LiC 6 spectra to band structure calculations by Holzwarth et al 13 The present letter reports transmission EELS measurements of the Li K edge in intercalated graphite and in metallic Li.…”

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confidence: 99%

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Electron energy-loss spectrometry on lithiated graphite

Hightower

Ahn

Fultz

et al. 2000

Applied Physics Letters

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Transmission electron energy-loss spectrometry was used to investigate the electronic states of metallic Li and LiC 6 , which is the Li-intercalated graphite used in Li-ion batteries. The Li K edges of metallic Li and LiC 6 were nearly identical, and the C K edges were only weakly affected by the presence of Li. These results suggest only a small charge transfer from Li to C in LiC 6 , contrary to prior results from surface spectra obtained by x-ray photoelectron spectroscopy. Effects of radiation damage and sample oxidation in the transmission electron microscopy are also reported. © 2000 American Institute of Physics. ͓S0003-6951͑00͒04428-4͔Lithiated graphite is the standard anode material in Liion rechargeable batteries. 1 Highly crystallized graphite can intercalate Li atom to a maximum composition of LiC 6 . This is equivalent to a specific charge of 372 Ah kg Ϫ1 , 2 although in practice graphite anodes have specific energies of 320-360 Ah kg Ϫ1 . Graphite anodes have high voltages of 3-4 V versus the cathode, but the difference in electrochemical potential between metallic Li and lithiated graphite is small, of order 0.01 V. The intercalation of Li into highly crystallized graphite changes the stacking sequence of the hexagonal planes from an ABABAB to AAAAAA. 3 This change in stacking sequence and the high chemical potential of Li in graphite suggest that a better understanding of the interlayer states of LiC 6 may facilitate improvements to Liion electrochemical cells.The results of numerous studies on the band structure of Li intercalated graphite demonstrate the difficulty in determining the degree of hybridization between Li atomic orbitals and graphite interlayer states. Early theoretical calculations of the LiC 6 band structure began with the notion of complete charge transfer of Li valence electrons to the graphite p bands. 4,5 This evolved into an elegant theory of alkali-intercalated graphite interlayer states as interacting nonorthogonal hybrid states of Li 2s and graphite interlayer states. 6,7 This gives credence to x-ray photoelectron spectroscopy ͑XPS͒ results by Momose et al. 8 and others 9 claiming Li to be intercalated into graphite as ionic Li ϩ . Early experimental work by Grunes et al. 10 using electron energy-loss spectroscopy ͑EELS͒ demonstrated distortions of the graphite band structure upon intercalation of alkali metals. Hartwigsen et al. 11 used a density functional theory, local density approximation to determine the degree of charge transfer from Li to the intercalant host lattice to be 0.5e for LiC 6 and 0.4e for LiC 8 . Further experiments using inelastic x-ray scattering spectroscopy by Schülke 12 were able to correlate features of LiC 6 spectra to band structure calculations by Holzwarth et al. 13 The present letter reports transmission EELS measurements of the Li K edge in intercalated graphite and in metallic Li. After showing oxidation tendencies of the transmission electron microscopy ͑TEM͒ samples and how this was controlled, we show that the Li K edge for Li in LiC 6 ...

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confidence: 60%

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confidence: 81%

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confidence: 99%

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Electron energy-loss spectrometry on lithiated graphite

Hightower

Ahn

Fultz

et al. 2000

Applied Physics Letters

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“…Because of the high surface area of graphite particles as compared to the lithiummetal electrode, the role of contaminants, such as HF in LiPF 6 and LiBF 4 -based electrolytes, is much less pronounced. 96 The beneficial effect of inorganic additives, such as CO 2 , N 2 O, S x 2− , etc., on the formation of the SEI on carbons, was emphasized. 94,95,97 Interesting results were obtained by Ein-Eli et al, 98 who showed that the use of SO 2 as an additive to LiAsF 6 /MF or LiAsF 6 /PC, DEC, DMC solutions offers the advantage of forming fully developed passivating films on graphite at a potential much higher ( 99 found that for graphite electrodes an EC+DEC solvent mixture is preferred over EC+DME with respect to the formation of a stable passivating film.…”

Section: Carbonaceous Electrodesmentioning

confidence: 99%

Review—SEI: Past, Present and Future

Peled

Menkin

2017

J. Electrochem. Soc.

1,603

1,474

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The Solid-Electrolyte-Interphase (SEI) model for non-aqueous alkali-metal batteries constitutes a paradigm change in the understanding of lithium batteries and has thus enabled the development of safer, durable, higher-power and lower-cost lithium batteries for portable and EV applications. Prior to the publication of the SEI model (1979), researchers used the Butler-Volmer equation, in which a direct electron transfer from the electrode to lithium cations in the solution is assumed. The SEI model proved that this is a mistaken concept and that, in practice, the transfer of electrons from the electrode to the solution in a lithium battery, must be prevented, since it will result in fast self-discharge of the active materials and poor battery performance. This model provides [E. Peled, in "Lithium Batteries," J.P. Gabano (ed), Academic Press, (1983), E. Peled, J. Electrochem. Soc., 126, 2047Soc., 126, (1979.] new equations for: electrode kinetics (i o and b), anode corrosion, SEI resistivity and growth rate and irreversible capacity loss of lithium-ion batteries. This model became a cornerstone in the science and technology of lithium batteries. This paper reviews the past, present and the future of SEI batteries. The PastPrior to the publication of the SEI model (1979), 1,4 researchers used the Butler-Volmer equation, in which direct electron transfer from the electrode to lithium cations in the solution is assumed. It was generally assumed that the rate-determining step (RDS) is the transfer of electrons from the metal to the cations in the solution. Researchers found that the lithium anode is covered by a passivating layer which interferes with the deposition/dissolution process of the anode. Brummer and Newman 2,3 concluded that a passivating anode can offer only a limited cycle life and in order to obtain a deep-discharge high-cycle-life secondary battery, the lithium anode must be free of a passivating layer and kinetically stable with respect to the electrolyte. The SEI model proved that this is a mistaken concept and that, in practice, the transfer of electrons from the electrode to the solution in a lithium battery, except when forming a SEI, must be prevented. The Present, Lithium-Metal and Lithium-Ion BatteriesIntroduction.-It is now generally accepted that the solidelectrolyte interphase (SEI) is essentially for the existence and successful operation of lithium-and sodium-battery systems, as primary and secondary power sources. 4 In 1979, it was proposed by Peled,

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“…The small signal at 288 eV can be assigned to carbon atoms from LiC 6 compounds. The core level of C (1s) of lithium-intercalated graphite is higher than that of conventional graphite, suggesting that charge redistribution results in the shifting of Fermi level of graphite [26].…”

Section: Microstructure and Compositionmentioning

confidence: 95%