The lithium intercalation properties of SnSb/MCMB core-shell composite as the anode material for lithium ion battery

Abstract

SnSb/MCMB composite material was prepared by multi-step synthesis methods. Mesocarbon Microbeads (MCMB) powders were modified by acid treatment firstly, and then SnSb nano particles were deposited on the surface of MCMB through chemical reduction method forming a core-shell composite structure. To characterize the phase and morphology of the composites material, X-ray diffraction (XRD), scanning electron microscope (SEM) were used. The constant current charge and discharge (CD) and cyclic volt ampere (CV) methods were also used to test the electrochemical performance of SnSb/MCMB. The results demonstrated that SnSb/MCMB presents a multiphase system of nanocrystalline and amorphous structure. The capacity attenuation of SnSb alloy is faster than that of SnSb/MCMB. For the SnSb/MCMB composite, the tiny alloy particles were dispersed on the surface of MCMB powders, preventing from the serious agglomeration of nano particles. At the same time, the inner core MCMB can also buffering the volume effect of the alloy compoites to improve the elecrtochemical cycling stability. The composite material was a first discharge specific capacity of 936.161 mAh/g and the first Coulomb efficiency 80.3%. The specific capacity was still up to 498.221 mAh/g after 50 cycles.