Fast and Reversible Na Intercalation in Nsutite‐Type VO₂ Hierarchitectures

Abstract Sodium‐ion batteries (SIBs), owing to the natural abundance and low cost of sodium resources, are the promising alternative to lithium‐ion batteries (LIBs) in the field of large‐scale energy storage. Nevertheless, the development of appropriate anodes for SIBs is still a challenge. Vanadium oxides with diverse crystallographic structures and high theoretical capacities hold large opportunities to construct high‐performance SIBs. Among them, new‐state nsutite‐type VO₂ (VO₂(N)) produced by the random intergrowth of rutile VO₂(R) (superior structural stability but sluggish kinetics) and paramontroseite VO₂(P) (high electronic/ionic conductivity but weak structural stability) have ample opportunity to obtain desirable sodium storage performance with high capacity, long lifespan, and rapid reaction dynamics. Herein, the spindle‐like VO₂(N) is developed through a simple hydrothermal approach. It demonstrates a Na⁺ (de)intercalation mechanism and exhibits a high capacity of 411 mAh g⁻¹ at 50 mA g⁻¹ as well as outstanding high‐rate cyclic stability (103 mAh g⁻¹ at 10 A g⁻¹ over 6000 cycles). Furthermore, a high‐performance VO₂(N)||Na₃V₂(PO₄)₂O₂F full cell is developed, which shows that the VO₂(N) anode has the potential for practical use.