Adsorption Of Lithium Atoms Research Articles

Adsorption and diffusion behavior of lithium atom on boron-doped armchair graphene nanoribbon- A dispersion-corrected DFT study

In this paper, we study the relevance of considering dispersion interactions in DFT calculations to determine the adsorption behavior of lithium atom(s) on boron-doped armchair graphene nanoribbons. Our findings suggest that substitutional doping with boron atoms makes the AGNR electron-deficient which results in charge transfer from Li to the AGNR. Li atom binds more strongly to B-doped AGNR than pristine AGNR. A stronger Li-C interaction prevents the clustering of Li atoms, thus, inhibiting dendrite growth. The maximum storage capacity of B-doped AGNR reaches to 1261 mAh/g. B-doped AGNR offers a lower diffusion barrier of 0.19 eV to Li atom as compared to pristine AGNR. From the analysis of density of states, it is observed that the semiconducting nature of both pristine and B-doped AGNRs turns into metallic after the adsorption of lithium atom. Our results show that B-doped AGNR can be used as a potential anode material of lithium-ion batteries.

First-Principles Study on the Structural, Electronic, and Lithium Storage Properties of Ti3C2T2 (T = O, F, H, OH) MXene.

The structures of bare Ti3C2 and functionalized Ti3C2T2 (T = O, F, H, OH) MXenes were constructed, and the effect of surface functional groups T2 (T = O, F, H, OH) on the structural, electronic, and lithium storage properties were investigated by first-principles calculations. The results show that the proximity of surface functional groups will induce some lattice distortion of Ti3C2T2 MXene. The degree of lattice distortion depends mainly on the adsorption position of functional groups and the types of surface functional groups. From the point of view of forming energy, the surface functional groups tend to be located at the CCP site. From the energy band and DOS results, the presence of surface functional groups has a significant effect on the valence band, while it has a slight impact on the conduction band. In terms of lithium storage, lithium atom adsorption starts from the HCP position for bare Ti3C2, while functionalized Ti3C2T2 starts from the CCP position. The double-layer lithium storage capacity of bare Ti3C2 and Ti3C2O2 were 639.78 mAh/g and 537.22 mAh/g, respectively. And the single-layer lithium storage capacity of Ti3C2F2 was 130.77 mAh/g.

Atomistic insights into lithium adsorption and migration on phosphorus‐doped graphene

AbstractWe present a comprehensive density functional theory study of the effects of phosphorus doping of graphene on adsorption and diffusion behavior of lithium. We find that protrusion introduced by phosphorus doping enhances the adsorption of a single lithium atom onto graphene due to an additional partial covalent bonding between lithium and carbon atoms of the substrate. With an increase in concentration of lithium atoms, cluster formation is observed near the phosphorus dopant. Finite density of states at Fermi level indicates the electronic conductivity of phosphorus‐doped graphene before and after the adsorption of a lithium atom. An increase in density of states above the Fermi level is observed with increased lithium concentration. The protrusions caused by phosphorus dopants act as trapping centers for lithium, thereby hindering their migration over the substrate. This atomic level study can act as a guideline for further development of electrode materials for novel battery technologies.

Effect of H Defects on Li Transport during the Deposition Process on an H‐Diamond Surface: A First‐Principles Calculation Analysis

AbstractTo explore the feasibility and rationality of a hydrogen‐terminated diamond surface film as an solid electrolyte interface (SEI) for lithium‐sulfur batteries, the adsorption and migration behavior of lithium atoms on the hydrogen‐terminated diamond surface with different amounts of hydrogen defects are determined by first‐principles calculations. Since a hydrogen deficiency in the row direction is denser than a hydrogen deficiency in the chain direction, hydrogen deficiency can drive lithium‐ion deposition. Thus, lithium atoms are more stable on the surface of hydrogen‐terminated diamonds with a hydrogen deficiency in the direction of the dimer row. The adsorption of lithium atoms on hydrogen‐terminated diamond films lacking three hydrogens is more stable due to the absence of dangling chemical bonds on the surface of the hydrogen‐terminated diamond. Therefore, lithium atoms cannot be adsorbed on an all‐H‐diamond surface. The low adsorption energy of lithium atoms on a clean diamond surface indicates that it is a simple physical adsorption. H termination increases the adsorption energy and migration activation energy of Li on the diamond surface. H termination changes the migration path of Li on the diamond surface. The atomic deposition of Li is driven by the center of the H defect region on the H‐diamond surface.

Lithium Storage on Extended Graphynes: Predicted by DFT Calculations†

Graphyne,which contains planar sheets equally occupied by sp2 and sp carbon atoms,is a layered carbon allotrope. Since the length of the acetylene chains within graphyne can be variable by adjusting the number of acetylenic linkages( —C ≡ C—) between carbon hexagons,resulting in a family of graphyneextended graphynes( i. e. graph-n-ynes). In this work,density functional theory( DFT) calculations were carried out to investigate the adsorption of lithium atoms on extended graphynes monolayers,and the results were compared to extrapolate the potential relationship between lithium storage capacity and the number of acetylenic linkages. The results show that further extending the acetylenic chains might not be helpful in achieving higher capacity. The longer acetylene chains result in the lower carbon atom density,as well as the lower stability of the carbon networks,which should be taken into consideration seriously. High-capacity Li storage as LiC3 in graphdiyne and graph-5-yne,was achieved,and the preferred adsorption sites for Li were identified computationally. With high Li storage capacity and structural advantages,these porous carbon materials are expected to be applied in efficient lithium storage.

Chains of benzenes with lithium-atom adsorption: Vibrations and spontaneous symmetry breaking

We study effects of different configurations of adsorbates on the vibrational modes as well as symmetries of polyacenes and poly-p-phenylenes focusing on lithium atom adsorption. We found that the spectra of the vibrational modes distinguish the different configurations. For more regular adsorption schemes the lowest states are bending and torsion modes of the skeleton, which are essentially followed by the adsorbate. On poly-p-phenylenes we found that lithium adsorption reduces and often eliminates the torsion between rings thus increasing symmetry. There is spontaneous symmetry breaking in poly-p-phenylenes due to double adsorption of lithium atoms on alternating rings.

Calculation of Adsorption Parameters for Lithium on Carbon Nanotube (7,7) with a Double Vacancy

The adsorption of lithium atoms on carbon nanotubes with double vacancy structural defects (2V-defect) is being studied with first-principle modeling. The structure of defective tubes in ground state is considered, the role of effects related to finite sizes of a model is evaluated. It is demonstrated that the location of a carbon 8-ring formed by 2V-defect above the center is the most preferable for a lithium atom.

Density Functional Theory Study of Lithium Atom Adsorbing in the Interior and Exterior of a Series of Carbon Nanotubes

Density functional theory has been applied to study of adsorption of lithium atom in the interior and exterior of a series of carbon nanotubes. It is found that lithium atom can steadily adsorb in the interior and exterior of carbon nanotube. Lithium atom adsorbs at the center and near the sidewall for interior of carbon nanotube, but lithium atom only adsorbs near the sidewall for exterior of carbon nanotube. The interior of small diameter carbon nanotube is more favorable than larger ones for lithium atom adsorbing. This is because the lithium atom almost locates at the center of small diameter carbon nanotube, leading to strong interaction. Moreover, we also investigate the lithium atom of adsorption distance, Mulliken population and the system of the redistribution of electron density.

Theoretical study of adsorption of lithium atom on carbon nanotube

We investigate the adsorption of lithium atoms on the surface of the (12,0) single wall carbon nanotube (SWCNT) by using ab initio quantum chemical calculations. The adsorption of one lithium atom on the inside of this SWCNT is favored compared to the outside. We check this feature by charge transfer and regional chemical potential density. The adsorption of multiple lithium atoms on the interior of the SWCNT is studied in terms of adsorption energy and charge transfer. We show that repulsive force between lithium atoms destabilizes a system for the large number of lithium atoms.

First-Principles Study of Lithium Absorption in Boron- or Silicon-Doped Single-Walled Carbon Nanotubes

The lithium absorption energies and electronic structures of boron- or silicon-doped single-walled carbon nanotubes (SWCNT) were investigated using first-principles calculations based on the density-functional theory. As B and Si doping carbon nanotubes, the lithium atom adsorption energies decrease. The effects of B and Si doping are different on the lithium atomic adsorption. B-doping forms an electron-deficient structure in SWCNT. While the Si-doping forms a highly reactive center. The calculations suggest that boron- and silicon-doping in SWCNT will improve Li absorption performance.

Theoretical investigation on the adsorption of lithium atom on the Si n cluster ( n=2–7)

Ab initio calculations are carried out to study the adsorption of Lithium atom on the Si n cluster with n ranging from 2 to 7. At the MP2/6-31G(d) level, the structures of the neutral Si n clusters and the Si n Li clusters ( n=2–7) are optimized. The single-point energy at QCISD/6-311+G(d,p) level for the optimized isomers are further performed. Harmonic vibrational frequency analysis at the MP2/6-31G(d) level is also undertaken to confirm that the optimize geometries are stable. Based on our results, the most favorable sites for Li adsorption on the Si 2–7 clusters are the bridge sites. In addition, the vertical ionization energies of the Si n Li clusters and the electron affinities of the Si n clusters are also calculated. The clear parallelism between the vertical ionization energies of Si n Li and the electron affinities of Si n is found. This is consistent with the fact that the framework of the Si n in the Si n Li cluster is similar to the structure of the corresponding negative ion Si n − .

Lithium adsorption on TiO2: studies with electron spectroscopies (MIES and UPS)

The adsorption of lithium atoms on rutile TiO2(110) single crystals was studied with metastable-induced electron spectroscopy (MIES) and ultraviolet photoelectron spectroscopy (UPS(HeI)) between 130 K and room temperature. Some auxiliary measurements on W(110) required for data interpretation are also reported. At 130 K ionic adsorption at titania prevails up to 0.3 monolayer equivalents (MLE) as judged from the weak Li(2s) emission in MIES for these exposures. The reduction of the Ti4+ cation is manifested by the growth of an occupied bandgap state in UPS: the alkali s-electron is transferred to a near-surface cation, thereby reducing it to Ti3+ 3d. The transfer of the s-electron is responsible for the observed work function decrease up to ∼0.5 MLE coverage. From the analysis of the UPS Ti3+ 3d signal, as well as from the Li(2s) emission, it is concluded that the degree of ionicity of the adsorbed Li decreases from 100% at 0.3 MLE to 40% at 0.7 MLE. Above 0.5 MLE the MIES spectra are dominated by an Li(2s)-induced peak indicating the presence of Li with an at least partially filled 2s orbital. At temperatures above 160 K this peak is almost absent. Excluding Li desorption at these temperatures, we suggest that Li moves into or below the rutile TiO2(110) surface above 160 K. Lithium insertion into the surface and intercalation are discussed. Copyright © 2004 John Wiley & Sons, Ltd.

AC impedance study on the interface between organic electrolyte and amorphous $WO_3$ thin film relating to the electrochemical intercalation of lithium

To AC impedance study was performed in this study on the interfacial reaction between organic electrolyte and amorphous tungsten oxides thin film, cathodically coloring oxide, prepared by e-beam evaporation method in the 1 M organic solution. The electrochemical reactions at the interface were analyzed by the transient method and the complex impedance spectroscopy. The impedance spectrums showed that the electro-chemical intercalation of lithium cations was consisted of the following three steps; the first step, the charge transfer reaction of lithium cation at the interface between amorphous tungsten oxides thin film and the organic electrolyte, the second step, the adsorption of lithium atom on the surface of amorphous tungsten oxides thin film, and then the third step, the absorption and the diffusion of lithium atom into amorphous tungsten oxides thin layer. The bleaching and the coloring characteristics of amorphous tungsten oxides thin film were explained in terms of thermodynamic and kinetic variables, the simulated and by CNLS fitting method. Especially it was found that the limiting values of electrochromic reaction were the molar ratio of lithium, y=0.167 and the electrode potential, E=2.245 V (vs. Li).

Lithium-induced reconstructions of the Si(001) surface

We report the new LEED observation that lithium atom adsorption on a Si(001) surface at room temperature or below produces a series of ordered phases, (2×2):Li → (2×1):Li → c(3√2 × √2)R45°:Li → streaky c(3√2 × √2)R45°:Li → (4×1):Li → (1×1):Li, depending on adsorbate coverage. This observation partially contradicts previous studies which reported only two phases in the series. We discuss possible origins of the controversy. We then propose a structural model that may account for the sequential appearance of the phases most naturally by invoking a spin-flip mechanism of an impurity stabilized magnetic system. The results suggest that the first phase be a reconstruction of the silicon substrate induced by Li adsorption where asymmetric dimers arrange themselves ferromagnetically and antiferromagnetically along the [11̄0] and [110] directions, respectively.

Lithium-atom adsorption on Si(001)2 x 1: Properties of lithium overlayer different from other alkali-metal atoms

Lithium-atom adsorption on Si(001)2 x 1 has been studied by electron energy loss spectroscopy (EELS). No overlayer plasmon (OLP) is observed even at high lithium-atom coverage. By contrast, sodium, potassium, rubidium and cesium monolayers show prominent peaks of OLP in EEL spectra. It is shown that the structure and electronic properties of lithium overlayers are also different from those of other alkali-metal atoms. This is deduced by low energy electron diffraction, Auger electron spectroscopy and work-function measurement.

Lithium-atom adsorption on Si(001)2 × 1: Properties of lithium overlayer different from other alkali-metal atoms

Lithium-atom adsorption on Si(001)2 × 1 has been studied by electron energy loss spectroscopy (EELS). No overlayer plasmon (OLP) is observed even at high lithium-atom coverage. By contrast, sodium, potassium, rubidium and cesium monolayers show prominent peaks of OLP in EEL spectra. It is shown that the structure and electronic properties of lithium overlayers are also different from those of other alkali-metal atoms. This is deduced by low energy electron diffraction, Auger electron spectroscopy and work-function measurement.