First principle modeling of a silicene anode for lithium ion batteries

Electrochimica Acta, Volume 378, 2021, № 138143

A.Y.  Galashev, A.S. Vorob’ev

Abstract — This work is devoted to a first principle study of changes in the structural, energy, and electronic properties of a silicene anode, represented by a bilayer silicene, as it is filled with lithium. The parallel folded silicene sheets form a flat channel with an initial gap of 0.75 nm. Lithium atoms were deposited both inside and outside the channel. The ratio of the amount of lithium to silicon varied in the range from 0.1 to 2.3. The maximum number of lithium atoms in the channel is revealed, which does not lead to defect formation in the silicene walls. The types of clusters in the formed packing of lithium atoms are defined and their stability is investigated. The tensile limit of silicon bonds in silicene sheets is found. The cohesive energy between the surfaces formed by lithium and the walls of the silicene channel has been established at various ratios of lithium to silicon. The change in the volume of the silicene channel is calculated depending on the amount of lithium deposited on it. The gravimetric capacities for different degrees of filling of the silicene anode with lithium were obtained. The voltage profile of the simulated anode was determined. The conductor-semiconductor and semiconductor-conductor transitions were found when the silicene channel was filled with lithium.

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