Density functional theory including gradient correction and periodic boundary conditions was used for quantum-chemical modeling of the structural reorganization of silicon rods in processes of lithium insertion and extraction. The Li/Si ratios were considered over a concentration range from 3/1 to 1/8. It was found that after Li insertion, the regular structure of Si rods is distorted, and they become amorphous. At Li/Si ratio ∼ 1/1 and higher, after coating of rod surface by Li atoms or removing them from the surface layer of the rod and consequent annealing at moderate temperatures (400 - 600 K), a rapid (∼ 10 picoseconds) recovery of the uniform distribution of lithium atoms within silicon rod volume occurs. However, at low concentrations of lithium (Li/Si < 1/2), alignment does not occur. The results of this study clarify the limiting conditions for cycling without destruction of silicon rods, promising negative electrode materials for lithium-ion batteries.

包括梯度校正和周期性边界条件在内的密度泛函理论被用于硅棒在锂的插入和提取过程中的结构重组的量子化学建模。认为Li / Si比在3/1至1/8的浓度范围内。发现插入锂后，硅棒的规则结构变形，并变成非晶态。当Li / Si比约为1/1或更高时，在用棒上的Li原子覆盖棒表面或将其从棒的表面层中去除后，在中等温度（400-600 K）下进行退火，从而很快（约10皮秒）在硅棒体积内发生锂原子均匀分布的恢复。但是，在低浓度的锂（Li / Si <1/2）下，不会发生取向。