Computational investigation of silicene/nickel anode for lithium-ion battery

Abstract

Silicon-based anodes are distinguished by an exceptionally high energy capacity, which is an order of magnitude superior to that of a graphite anode. The thin-film design of the anode creates the conditions for increasing the specific energy, energy density and power density of LIB. Bilayer silicene on a nickel substrate is the anode material that can increase LIB performance. In the present work, using the molecular dynamic method, a detailed analysis of the packings of lithium atoms in silicene channels with different types of walls is performed. The occupancy of the channels with lithium depends on the type of defects present in its walls. Lithiation and delithiation are carried out in the presence of a constant electric field. The type of substrate affects the packing of lithium atoms in the channel and consequently on battery capacity and performance. The maximum filling of the lithium channel is achieved when monovacancies are present in silicene sheets. It is shown that the most preferable location of Li atoms in a channel is their location over hexagonal Si cells. The most significant stresses in silicene σzz are maximal in the presence of trivacancies in silicene sheets.