Enhanced Electrochemical Performance of a Tin-antimony Alloy/N-Doped Carbon Nanocomposite as a Sodium-Ion Battery Anode

A simple one-pot process for producing 3.5nm diameter uniformly dispersed SnSb nanoparticles on a nitrogen-doped carbon composite (NC) is reported. An ethanol slurry of SnCl4, SbCl3, and nitrilotriacetic acid (NTA) is heated in air to 300 degrees C to form the mixed metal oxide NTA complex; heating to 650 degrees C under argon yields the SnSb/NC nanocomposites, comprising 3.5nm diameter SnSb nanocrystals uniformly distributed in the conductive N-doped carbon. After 200 cycles at a specific current of 0.1Ag(-1), the SnSb/NC nanocomposite sodium-ion anode retains a reversible capacity of 244mAhg(-1). The similarly prepared Sn/NC and Sb/NC anodes retain lower capacities of 88 and 188mAhg(-1), respectively. The improved performance of the SnSb/NC electrode might be ascribed to the stepwise sodiation/desodiation process of Sn and Sb species in the SnSb/NC electrode, which could act as an inert buffer matrix for each other, according to the potentials, slowing the capacity fading.