Sb-AlxCy-C Nanocomposite Alloy Anodes for Lithium-Ion Batteries

Abstract

We present a facile approach to making Al-Sb, carbon-modified (Al-Sb-C) nanocomposites for use as new anode materials in lithium-ion batteries (LIB). Alloying is achieved by one step synthesis using high energy mechanical milling (HEMM), producing nanometer-sized alloy particles of Sb-AlxCy-C. Based on electrochemical analyses, we determined that Sb acts as an active material, and both Al and carbon create a hybrid buffering matrix that mitigates the volume expansion of the active material during lithiation/delithiation to a greater degree than that by a pure metallic matrix (AlSb). In addition, we optimized the stoichiometric ratio of Al and Sb with regard to specific capacity and cycling performance. Of the ratios tested, a 1:1 molar ratio of Al and Sb exhibited the best cycling performance (302.5mAhg−1 after 200 charge/discharge cycles). Although our Al-Sb-C composite had low initial coulombic efficiency (∼59%), recovery to∼97% occurred within three cycles, indicating that initial side reactions are quickly reduced over the course of cycling. AlSb-C anodes also showed good rate capability and volumetric capacity. Overall, the new AlSb-C composite is a promising candidate for use as negative electrodes in lithium-ion batteries, providing an alternative to commercially available graphite electrodes.