Electronic Properties and Structure of Silicene on Cu and Ni Substrates

Abstract

Silicene, together with copper or nickel, is the main component of electrodes for solar cells, lithium-ion batteries (LIB) and new-generation supercapacitors. The aim of this work was to study the electronic properties and geometric structure of “silicene–Ni” and “silicene–Cu” systems intended for use as LIB electrodes. The densities of electronic states, band structures, adhesion energies and interatomic distances in the silicene–(Cu, Ni) systems were determined by ab initio calculations. Silicene on a copper substrate exhibited temperature stability in the temperature range from 200 to 800 K, while on a nickel substrate, the structure of silicene was rearranged. Adsorption energies and bond lengths in the “silicene–Cu” system were calculated in the range of Li/Si ratios from 0.125 to 0.5. The formation of the Li2 isomer during the adsorption of lithium in a ratio to silicon of 0.375 and 0.5 was observed. Silicene was found to remain stable when placed on a copper substrate coated with a single layer of nickel. The charge redistribution caused by the addition of a nickel intermediate layer between silicene and a copper substrate was studied.

Computational Modeling of Doped 2D Anode Materials for Lithium-Ion Batteries

“…The influence of the thickness of the FCC nickel substrate with the (001) face towards silicene on the adhesion of silicene to Ni was studied in [ 49 ]. The difference in adhesion energies in the presence of four and five layers of atoms in the substrate was ~1%.…”

“…In the MD ab initio calculations, the Born–Karman periodic boundary conditions were used. The models used are described in more detail in [ 46 , 47 , 48 , 49 , 50 , 51 ].…”

“…Silicene has been the subject of a large number of papers, including review papers (see, for example, [ 31 , 32 , 33 , 34 ]). The possibility of using silicene as an anode material for LIBs was studied by the molecular dynamics method [ 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 ] and using quantum mechanical calculations based on the density functional theory (DFT) approximation [ 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 ]. However, a thorough analysis of calculations on the use of silicene in energy storage devices has not been conducted.…”

Computer development of silicene anodes for lithium-ion batteries: A review

“…DFT modeling of silicene placed on metal (Al, Cu, Ni, Ag, and Au) substrates was performed in [158][159][160] and on a graphite substrate in [4]. The use of SIESTA [161] or VASP [162] programs without changing the basic codes when modeling heterostructures, extended by periodic boundary conditions, require the creation of a single period of spatial translations.…”

“…In [160], the silicene-copper substrate systems with an intermediate nickel layer between silicene and copper were studied based on quantum mechanical calculations. The initial systems were created by replacing the upper layer of the copper substrate with one layer of nickel (with a copper substrate thickness of 2-4 layers).…”