锡镍合金负极材料Li嵌入性质的平面波赝势方法研究

Plane-Wave Pseudo-Potential Method of Li Inserted as Anode Material in Sn-Ni Alloy

利用基于密度泛函理论的第一性原理平面波赝势方法,对锡镍合金Ni2Sn和LiNi2Sn的电子结构进行计算。结果表明:负极材料Ni2Sn在脱嵌锂后,大量的镍原子将以团聚形式游离出来缓冲体积膨胀,体积膨胀率为8.418%,同时部分镍原子与锡原子形成较强共价键稳定基体骨架,抑制体积效应从而提高循环性能。这与实验规律一致。

Based on the density functional theory of first-principle, this paper calculates the electronic structures of Ni2Sn and LiNi2Sn alloys with plane wave pseudo-potential method. The results show that the dispersed nickel atoms act as a buffer to suppress or accommodate the large volume expansion after lithium ion is inserted in Ni2Sn anode material with a volume expansion ratio of 8.418%. Meanwhile, the covalent bond between partial nickel atoms and tin atoms will steady the framework of matrix, which suppresses the volume effect and improves the cycle properties. And this result is consistent with the result of experiments.