A density functional theory study of high-performance pre-lithiated MS2 (M = Mo, W, V) Monolayers as the Anode Material of Lithium Ion Batteries

Abstract

Recent experimental study shows that the pre-lithiated MoS 2 monolayer exhibits an enhanced electrochemical performance, coulombic efficiency of which is 26% higher than the pristine MoS 2 based anode. The underlying mechanism of such significant enhancement, however, has not yet been addressed. By means of density functional theory (DFT) calculations, we systematically investigated the adsorption and diffusion behavior of lithium (Li) atoms on the MS 2 (M = Mo, W, V) monolayers. on the pre-lithiated MS 2 monolayers, the adsorption energy of extra Li ions are not significantly changed, implying the feasibility of multilayer adsorption. Of importance, the Li diffusion barriers on pre-lithiated MS 2 are negligibly small because of the charge accumulation between the diffusing Li ions and the pre-lithiating Li layer. correspondingly, we report that the pre-lithiation should be a general treatment which can be employed on many transition-metal di-chalcogenides to improve their storage capacities and charge-discharge performance in Li ion batteries. in addition, we propose that the pre-lithiated VS 2 may serve as an outstanding anode material in LIBs.The Lithium-ion battery (LIB) has been regarded as one of the most indispensable and promising devices in the fields of telecommunications, electric automobiles and electric power grids 1,2 . Today, graphite is widely used as the anode material of commercial LIBs owing to its layered structure, good electric conductance and excellent chemical stabilities 3,4 . Nevertheless, the maximum specific capacity of lithium ions of graphite (LiC 6 ) is only 372 mA•h • g −1 . As a result, numerous researches have been devoted to the searches of new anode materials with higher energy densities 1,5-7 . In addition to the specific capacity, columbic efficiency has also been employed to evaluate the performance of electrodes in LIBs. Thus, an ideal anode material, should not only accommodate densely packed Li ions, but also allow for fast Li diffusions to promote the charge-discharge rate 1,8-10 . In the past decade, a number of two-dimensional (2D) materials, including transition-metal oxides, di-chalcogenides (MO 2 and MS 2 ) and BN, have been successfully synthesized [11][12][13] . Their electronics properties and potential applications in devices have also been explored and proposed as electrode material for LIBs 14-20 . Very recently, Yang et al. report that the coulombic efficiency of MoS 2 can be significantly improved by the pre-lithiation treatment, in which the MoS 2 is on direct contact with lithium foils 21 . Despite the improved performance of MoS 2 upon pre-lithiation, the underlying mechanism however, has not yet been addressed. Herein, systematic Density Functional Theory (DFT) calculations have been conducted to explore (i) the chemical insights of the enhanced performance after pre-lithiathion, and (ii) the effect of pre-lithiathion on other MS 2 nanosheets. Our results revealed that the pre-lithiathion allows for multilayer adsorption and fast diffusion of Li ions on ...

From absolute potentials to a generalized computational standard hydrogen electrode for aqueous and non-aqueous solvents

“…A-H + e À -A À + 0.5H 2 (5) Using this alternative formulation of an acid-base reaction we found, that the absolute potential in the solvent the pK a has been measured in (E abs (SHE)), can be computed through eqn (6). 42 E abs (SHE) = ÀnF[0.5G(H 2 ) + G(A…”

“…Under these circumstances, eqn ( 9) directly leads to reaction (5) and eqn (6). Assuming on the other hand a situation where the acid dissociation and the electrochemical reactions take place in different solvents, this expression no longer holds.…”

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Exploring the Full Potential of Functional Si2BN Nanoribbons As Highly Reversible Anode Materials for Mg-Ion Battery

“…Carbon-free clean energy economy aims to untying new high-density rechargeable battery technologies for the electrification of transport systems and for integrating renewable energies into the grid systems. In the current scenario, the demand for a rechargeable Li-ion battery (LIB) is continuously growing for powering electric vehicles as well as for various stationary applications ranging from laptops to mobile phones. , Now LIB technology is reaching its fundamental limits in terms of its energy density . The limited abundance of Li, which is geographically restricted to only a certain part of the world’s reserves, brings the risks of limited lithium supply at affordable prices.…”

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