Regulating (010) Exposed Facets of a Sb₂O₃ Anode to Achieve High-Performance Sodium-Ion Batteries

Antimony oxide (Sb₂O₃) exhibits a high theoretical capacity for sodium storage but suffers from poor reaction kinetics and significant volume expansion. Exposing specific crystal facets of an electrode material is considered to be an effective strategy to reduce the expansion ratio and ion diffusion barrier. Here, in situ TEM investigations and theoretical calculations indicate that the exposure of (010) facets in Sb₂O₃ ameliorates the expansion ratio and reduces the Na⁺ diffusion barrier to enhance reversible Na⁺ storage. Theoretical calculations also reveal that polyvinylpyrrolidone facilitates the exposure of (010) facets. A facet-engineered Sb₂O₃ nanobelt with exposed (010) facets (Sb₂O₃-(010)) demonstrates superior performance, including higher capacity, excellent rate performance, and enhanced cycling stability compared to conventional Sb₂O₃. Notably, at 60 °C, Sb₂O₃-(010) shows excellent sodium storage properties and even maintains an 80.6% capacity retention ratio after 200 cycles at 5.00 A g^-1. This work underscores the potential of crystalline facet engineering to improve sodium-ion battery performance.