A three-dimensional highly conductive structure of Si/NiSi2 anode for Li-ion battery

Abstract

The low conductivity, structural degradation during cycling and severe capacity loss in the initial cycle make silicon difficult to meet the increasing demand in various aspects as one of the promising anodes material. Here we introduce a conductive three-dimensional structure to tackle these problems. The design of the electrode is achieved via plasma enhanced chemical vapor deposition (PECVD) of silicon nanoparticles onto three-dimensional nickel foam, forming a 3D conductive network. The three-dimensional networks provide abundant electrochemical activity sites and conductive transport paths. Besides, this design can significantly improve the energy density of the electrode since no binders or conductive agents are deposited. The initial columbic efficiency of Si anode is greatly improved by tuning the deposition time. A secondary phase of NiSi2 is found from XPS results which serves as an inactive buffer matrix in the composite. The anode with 40min deposition time achieves remarkable electrochemical performance as 84.84% initial columbic efficiency and 525.5mAh·g−1 specific capacity after the 100th cycles. This preferable performance is the result of enhanced physical and mechanical properties of the electrode with a 3D conductive structure.