Li-Si合金中间相作为锂离子电池负极材料的研究(英文)

The Roles of Intermediate Phases of Li-Si Alloy as Anode Materials for Lithium-Ion Batteries

采用基于密度泛函理论的第一性原理平面波赝势方法计算了Li-Si各种合金相的物理性质和电化学性能。结果表明:除了在反应过程中生成传统的固态电解质SEI膜之外,形成的Li12Si7合金相也是部分导致首次不可逆容量损失的重要原因。另外,采用射频磁控溅射制备了纯Si薄膜电极,并运用XRD、循环伏安CV、恒流充放电CC表征和测试了材料的结构和电化学性能,结果表明首次不可逆容量损失非常大,无定型结构能有效抑制体积膨胀和改善循环性能。

An ab initio method of the first-principles plane-wave pseudopotentials based on the density functional theory has been used to calculate the physical character and electrochemical performance of various alloy phases in Li-Si alloy. The results show that besides the growth of solid electrolyte interphase (SET), the formation of Li12Si7 alloy phase also partly leads to the initial irreversible capacity loss. In addition, the pure silicon thin film electrode was prepared by the radio frequency (RF) magnetic sputtering on copper foil collector as anode materials. The structural and electrochemical characteristics of Li-Si alloy were examined using X-ray diffraction (XRD), cyclic voltammogram (CV) and repeatedly constant current charge/discharge (CC). The results show that the first irreversible capacity loss is very large and amorphous structure can accommodate the large volume expansions and improve cyclic performance.