Effect of TiC addition on SnSb-C composite anodes for sodium-ion batteries

Abstract

Tin-antimony alloy (SnSb) particles dispersed in a conductive matrix comprised of TiC and carbon have been synthesized by high energy mechanical milling (HEMM) and explored as anodes for sodium-ion batteries. The SnSb TiC C samples have been prepared with different TiC and carbon contents in the composite, characterized by X-ray diffraction before and after sodiation and by high-resolution transmission electron microscopy, and compared to SnSb C as a baseline. The SnSb TiC C anodes demonstrate better cyclic performance as well as better rate-capability compared to SnSb C. In addition, the increase in TiC content in the composite leads to better electrochemical performance. SnSb-TiC(40%)-C(20%) and SnSb-TiC(40%)-C(30%) electrodes exhibit the best electrochemical performance, which could result from both the well-developed SnSb as an electrochemically active nanocrystalline material and the conductive matrix composed of a combination of TiC and carbon. Additionally, the use of FEC electrolyte additive results in much better electrochemical performance even at high-rate current density when combined with this material due to the formation of a stable and thin SEI layer. (C) 2014 Elsevier B.V. All rights reserved.