Synthesis of Si-Zn2SiO4 composite as Li-ion battery anodes and its electrochemical mechanism analysis

Abstract

Zinc silicate (Zn2SiO4) is a promising anode material for Li-ion batteries, although its reversible capacity is relatively low. In this study, we designed a Si-Zn2SiO4 composite using a simple mechanical milling and heat treatment. The synthetic phase transformation from the starting materials to the final composite was confirmed via X-ray diffraction (XRD) analysis, and the morphology and microstructure of the composite were analyzed using electron microscopy techniques. The electrochemical test results demonstrated that the composite electrode exhibited a high reversible capacity of 715 mAh g–1 after 400 cycles without carbon incorporation. Further, the electrochemical reaction mechanism of the Si–Zn2SiO4 composite electrode with Li was investigated via ex situ XRD analyses. The stable cycling stability of the electrode was attributed to the role of Zn2SiO4 in buffering the volume change of Si.

Keywords

• Zinc silicate
• Silicon
• Anode
• Reaction mechanism
• Battery