Design of an ultra-stable Sb2Se3 anode with excellent Na storage performance.

Owing to the high theoretical capacity, Sb 2 Se 3 has been regarded as one of the best choices for Sodium-ion batteries (SIBs) anode materials. However, Sb 2 Se 3 anode suffers from huge volume change with poor electrode structure stability, resulting in limited cycling and rate performance. Herein, inspired by the formation of inclusion complex an effective strategy for improving unstable molecules in biological fields, we encapsulate Sb 2 Se 3 in capsular carbon shell via a hydrothermal and calcinations process. Furthermore, by adjusting the thickness of the capsule carbon shell, an ultra-stable Sb 2 Se 3 electrode structure is realized. Equipped with this ultra-stable electrode structure, Sb 2 Se 3 anode exhibits high capacity of 475 mA h g−1 at 2 A g−1 even after 600 cycles, showing compelling advantage on Na storage performance compared to other reported Sb-based anode materials. The analysis results indicate that the intact capsular carbon shell can effectively remit huge volume change of Sb 2 Se 3 , and act like a reaction vessel in which the sodiation/desodiation reaction of Sb 2 Se 3 is carried out regularly. Therefore, this ultra-stable electrode provides stable redox reactions, easy charge transfer and fast sodium ion diffusion, resulting in excellent Na storage performance of Sb 2 Se 3 anode. Encapsulating Sb 2 Se 3 in capsular carbon shell to from inclusion complex can achieve ultra-stable electrode structure with excellent Na storage performance. Image 1 • An ultra-stable Sb 2 Se 3 anode is realized by encapsulating Sb 2 Se 3 in a capsular carbon shell. • The as-prepared ultra-stable Sb 2 Se 3 anode exhibits high capacity of 475 mA h g−1 at 2 A g−1 after 600 cycles. • Forming inclusion complex is an effective strategy to achieve ultra-stable structure with good Na storage performance. [ABSTRACT FROM AUTHOR]