Dual‑carbon confined Sb2Se3 nanorods for potassium ion batteries anode with improved capacity and cycling stability

Abstract

Sb2Se3 is regarded as a promising conversion-alloying type anode material for potassium ion batteries (PIBs) owing to its high theoretical specific capacity. However, the low electric conductivity and large volume change during the charge/discharge process hinder its practical applications. Herein, we proposed a novel ‘dual carbon coating’ strategy to construct carbon confined Sb2Se3 nanorods for high performance PIBs anode. Owing to the enhanced electric conductivity resulted from the inner carbon and the strengthened mechanical stability from the outer graphene layer, the confined Sb2Se3 exhibit outstanding electrochemical potassium ion storage performances with a specific capacity of 482.1 mAh g−1 after 50 cycles at a current density of 0.1 A g−1. Even at a high current density of 1 A g−1 after 500 cycles, it still maintains a specific capacity of 283.7 mAh g−1. These results outperform the pure Sb2Se3 and those traditional ‘single carbon’ coated Sb2Se3 from both specific capacity and cycling stability. This ‘dual carbon coating’ method could also be applied to other conversion or alloying type anode materials of PIBs with high theoretical capacities and large volume variation during the repeated charge/discharge process.