Electronic structure of LiSi
Electronic structure of LiSi
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DOI：
10.1016/j.jallcom.2007.04.097
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发表时间：
2008-06
影响因子：
6.2
通讯作者：
Y. Kubota;M. C. Escaño;H. Nakanishi;H. Kasai
中科院分区：
文献类型：
--
作者：
Y. Kubota;M. C. Escaño;H. Nakanishi;H. Kasai
硅在锂离子电池（LIB）中特别受关注，因为它具有很大的理论比容量或体积容量。通过使用密度泛函理论 (DFT) 计算，研究了锂离子电池中硅负极的锂嵌入机制开始时最贫锂侧化合物 LiSi 的晶体结构、电荷分布和态密度。三棱锥由LiSi中的四个Li原子组成。与晶体硅的电荷密度相比，LiSi 中的 SiSi 共价键由于 Li 的嵌入而变弱。另一方面，与金属锂相比，硅化锂中锂原子周围的电子有所增加。 LiSi中的Li原子带负电荷为0.83-0.84。这些从Si原子中的p电子转移的电子主要由Li原子的p电子组成。当考虑从晶体Si到LiSi的锂嵌入反应时，平均嵌入电压约为0.4V。
Silicon is of special interest in lithium-ion batteries (LIBs) since it has large theoretical specific capacity or volumetric capacity. The crystal structure, charge distribution and density of states of LiSi as the Li-poorest side compound at the start of Li intercalation mechanism for Si anode in LIBs has been studied by using density functional theory (DFT) calculations. The triangular pyramids are formed by four Li atoms in LiSi. Compared to the charge density of crystalline Si, the SiSi covalent bonds in LiSi become weak due to Li intercalation. On the other hand, the electrons around the Li atoms in LiSi increase compared to those in metallic Li. The Li atoms in LiSi have negative charge of 0.83–0.84. These electrons, which are transferred from p electrons in the Si atoms, are mainly made of p electrons of the Li atoms. When considering the lithium intercalation reaction from crystalline Si to LiSi, the average intercalation voltage is about 0.4V.