Correlation between x-ray absorption and chemical potential measurements in lithium intercalated carbons

Abstract

Using synchrotron radiation we measured the x-ray absorption (XAS) near the C\ s edge for powdered graphite, boron substituted graphite, and a disordered graphitic carbon. The chemical potential of Li intercalated into the same carbons has also been measured as a function of x in Li x C6. When Li is intercalated, the 2s electron is transferred to the C host, filling the same levels as probed by XAS. In XAS, final-state energies contain a contribution from the electron-core-hole interaction which mimics the situation in Li intercalation where Li + interacts with conduction electrons. We show that XAS results correlate well with chemical potential measurements of intercalated Li made on the same materials. PACS numbers: 78.70.Dm, 71.20.-b, 82.45.+Z, 82.60.-s

High-Temperature Coulometric Titration of La1−xSrxCoO3−δ: Evidence for the Effect of Electronic Band Structure on Nonstoichiometry Behavior

“…This model, which relates variations in the Fermi level to changes in the concentration of ionized defects, is commonly referred to as electron gas rigid band model (electron gas RBM) (16). Although in this model important features like screening, electron correlation, and exchange are neglected, the observed chemical potential variations for alkali metal intercalated transition metal dichalcogenides have been found to correlate well with density of states calculations (17) and data from X-ray absorption measurements (18).…”

Thermodynamics and Transport of Ionic and Electronic Defects in Crystalline Oxides

“…Observed chemical potential variations for alkali-metal intercalated transition-metal dichalcogenides have been found to correlate well with density-of-states calculations 40 and X-ray absorption measurements. 41 McKinnon and Selwyn 42 criticized the validity of the electron-gas rigid-band model. With reference to the screened impurity rigid-band model developed by Friedel, 43 these authors proposed that, when ionized impurities are added or removed, the entire band shifts because of the perturbation constituted by the screened coulomb-potential of the impurity.…”

Use of the Rigid Band Formalism to Interpret the Relationship between O Chemical Potential and Electron Concentration inLa1−xSrxLankhorst1, Bouwmeester2, Verweij3 1996Phys. Rev. Lett.949560View full textAdd to dashboardCite

“…In this model, the Fermi level moves upwards as electrons are donated to the band, at a rate determined by the density of states at the Fermi level. Although in this simple model, commonly referred as electron gas RBM [10], important features like screening, electron correlation, and exchange are neglected, observed chemical potential variations for alkali metal intercalated transition metal dichalcogenides have been found to correlate well with density of states calculations [11] and x-ray absorption measurements [12]. It was even suggested to use the electronic structure of some intercalates as a criterion for the applicability as electrode material [13].…”