Si-Ni Alloy as Anode Materials for Lithium Ion Batteries: A First-Principles Study

Abstract

It is an efficient way for reducing the volume expansion ratio of Si-based anode materials by adding a second component to become Si-M systems. In this paper, based on first-principle plane wave method, Si-Ni alloy interphases was studied as anode materials for lithium ion batteries. The results show that the addition of Ni can reduce the volume expansion ratio of Si to some extent. And the volume expansion ratios of LiSiNi2 and LiSiNi3 were 32.451% and 32.753% respectively, which were smaller than other phases in Li-Si-Ni alloy. Based on the two key parameters(the volume expansion ratio and the lithium intercalation formation energy), it is considered that SiNi3 is the best one among the Si-Ni alloy interphases. The Li-Si covalent bonds are the main source of reversible capacity among the Li-Si-Ni alloy phases.