Carbon Hollow Tube-Confined Sb/Sb2S3 Nanorod Fragments as Highly Stable Anodes for Potassium-Ion Batteries.

Potassium-ion batteries (PIBs) have attracted widespread attention in recent years due to their potential advantages such as low cost and high energy density. However, the large radius of K+ and the low potassium storage capacity of some electrode materials limit their development. Antimony (Sb)-based materials are considered to be promising anode materials for PIBs in view of their high K storage capacity and low potassiation potential. Nonetheless, the huge volume variation caused by potassiation/depotassiation often leads to their failure. Previous works have proved that carbon coating and nanostructure design are important means to alleviate the volume effect. Herein, the carbon-coating technology and nanostructure design were combined to prepare a Sb-based nanomaterial with Sb/Sb2S3 hybrid nanorod fragments confined in a carbon hollow tube (Sb/Sb2S3@CHT). Such a nanostructure is beneficial to alleviate the volume change of the Sb/Sb2S3 hybrids while facilitating the kinetics of the electrochemical reaction. As a consequence, the Sb/Sb2S3@CHT anode electrode exhibits high rate performance and outstanding cycle stability characterized by retaining a high specific capacity of 400.9 mA h g-1 after cycling for 200 cycles at 200 mA g-1.