Structure and Electrochemical Properties of Si-Mn/C Core–Shell Composites for Lithium-Ion Batteries

A series of Si-Mn/C core–shell composites as anode materials is synthesized via a hydrothermal method combined with heating treatment. X-ray diffraction, Raman spectroscopy, x-ray photoelectron spectroscopy, scanning electron microscopy and transmission electron microscopy analysis are used to investigate the crystal structures and chemical compositions of all as-prepared composites. With the increase of Mn4Si7 alloy content in the Si-Mn/C composites, their cycle properties and rate capabilities increase first and then decrease. As a result, the obtained Si-Mn/C (9:1) displays the largest specific capacity of approximately 960 mAh/g after 100 cycles among all composites, and it can be sustained at 1 A/g with a reversible specific capacity of 460 mAh/g, demonstrating good electrochemical performance for Si-based anodes. Our study presents an ideal candidate to improve the mechanical integrity and electrochemical property of a Si-based anode for potential application in lithium-ion batteries.