Quantum-chemical modeling of lithiation–delithiation of infinite fibers [SinCm]k (k = ∞) for n = 12–16 and m = 8–19 and small silicon clusters

Resumo

In the framework of the search for promising anode materials for lithium-ion batteries and with the aim of studying the behavior of silicon–carbon composites during cycling, quantum-chemical modeling of the structure, stability, and electronic properties of silicon-coated carbon fibers has been performed. Calculations of loose infinite nanofibers [Si_nC_m]_k (k = ∞) for n = 12–16 and m = 8–19 have been performed by the density functional theory method with inclusion of gradient correction and periodic boundary conditions. It has been demonstrated that infinite nanofibers Si_nC_m have a large number of voids, promising for the accumulation of lithium without noticeable changes in lattice parameters, and a near-zero gap. The lithiation–delithiation of the Si₂₁ cluster and infinite nanofibers [Si₁₆C₁₉] for Li: Si = 1: 1, 2: 1, 3: 1, and 4: 1 has been modeled.