Nanodot‐in‐Nanofiber Structured Carbon‐Confined Sb2Se3 Crystallites for Fast and Durable Sodium Storage

Antimony‐based materials possess high specific capacity and appropriate redox potential for sodium storage, but they suffer from huge volume expansion/contraction when sodium ions insert/extract, which leads to inferior cycle life. Herein, a hierarchical nanodot‐in‐nanofiber structure is proposed to address this challenge, in which antimony selenide (Sb2Se3) nanocrystallites are confined by both 0D and 1D carbon layers. The multi‐pronged nanostructure reduces the size of active particles, alleviates the intrinsic volume change of Sb2Se3, and forms a stable transport network for charge carriers. Finally, the nanodot‐in‐nanofiber structured Sb2Se3 anode exhibits outstanding performance for sodium storage, such as high capacity and exceptional cycle lifespan for over 10 000 cycles at 2.0 A g−1. Therefore, this work can be valuable for the rational design of ultra‐stable alloy and conversion‐type materials in the application of next‐generation batteries. Carbon‐confined Sb2Se3 crystallites with nanodot‐in‐nanofiber structures are successfully fabricated through stepwise electrospinning, in situ substitution, and selenylation strategies. Benefiting from the synergistic effects of dual‐carbon confinement and uniformly distributed nanosize Sb2Se3, the composite presents a highly efficient sodium storage performance and an excellent lifespan over 10 000 cycles.