Sandwich-like heterostructured SnSb/MXene composite anode for enhanced sodium-ion storage performance

Abstract

Alloy-type SnSb is regarded as a potential candidate of Na-ion host material because of its high theoretical capacity achieved through reversible redox reactions. However, the drawbacks associated with massive volume variations limit its practical application. In this study, sandwich-like heterostructured composites composed of multilayered MXene and SnSb nanocrystals were prepared via a simple wet-chemical precipitation method. The multilayered MXene with mechanical robustness and high electrical conductivity helped to accommodate the severe volume changes of SnSb nanocrystals, and provide a sufficient conductive network that facilitated electron and Na-ion transportation, and participate in electrochemical reactions through its capacitive behavior. The uniformly embedded SnSb nanocrystals in the interlayer of MXene prevented the re-stacking of the MXene multilayer upon cycling. The SnSb/MXene composite anode exhibited remarkable reversible capacity (398 mAh g−1 at 100 mA g−1) with dramatically improved Na-ion storage performance regarding cyclability and rate capability compared to pure SnSb anodes.