Contribution of TiN to the enhanced cycling stability of Si@TiN/C composites as anode materials for Li-ion batteries

Abstract

• Si@TiN/C composites are prepared by solvothermal, ball milling and calcination. • TiN covers the surface of Si by chemical bonds, Si@TiN particles are wrapped by C. • Si@TiN/C composites exhibit superior cycling stability and high-rate performances. • The synergy of TiN and C gives buffer layer high strength and conductivity. In this paper, Si@TiN/C composites have been prepared by solvothermal process, mechanical blending and subsequent calcination under N 2 . The composites were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electrons microscopy and transmission electron microscopy. The contributions of TiN to the electrochemical properties of Si@TiN/C composites were further discussed by changing its relative contents in composites, respectively. The results indicate that cycling stability and high-rate property of Si@TiN/C composites are improved with the increasing of TiN content. The obtained Si@TiN(1:0.5)/C composites deliver a capacity retentions of 82.3% after 100 cycles at 0.5 A·g −1 and 74.3% after 200 cycles at 1 A·g −1 . Moreover, their specific capacities can still reach 710 mAh·g −1 even at 8 A·g −1 . The excellent electrochemical performances of Si@TiN/C composites should be attributed to the synergistic effect of TiN and C in composites, which makes the buffering matrix around Si particles have high conductivity and mechanical stability.