Preparation and Electrochemical Performance of SnSb-Ag Composite Alloy Anode Materials

Abstract

SnSb-Ag composite alloy anode materials were synthesized using chemical reduction method. Their microstructures, morphologies and electrochemical properties were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), constant current charge/discharge tests, cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The results indicated that the addition of Ag resulted in the formation of irregular layered structures and different void sizes after several charge/discharge cycles, which greatly reduced the distance of lithium ion diffusion and the occurrence of lithium trapping in the active electrode materials and increased the space available for volume expansion. Thus, the composite anode materials were protected from powdering and shredding, resulting in a greatly improved cycling stability. For example, the SnSbAg0.2 composite anode exhibited excellent cycle life by controlling the lithiation of the Ag, the reversible capacity for the 50th cycle was measured to be 518 mAh/g and the reversible capacity retention reached 82.04% between 0.1 V and 1.5 V.