Zinc Ferrite Nanorod‐Assembled Mesoporous Microspheres as Advanced Anode Materials for Sodium‐Ion Batteries

Mesoporous zinc ferrite (ZnFe 2 O 4 ) microspheres assembled by nanorods are fabricated through a facile hydrothermal approach, followed by a calcination strategy. The fabricated mesoporous ZnFe 2 O 4 has a diameter of approximately 500–800 nm with a high surface area of 91.6 m 2 g −1 . The utilization of the microspheres that serve as anode materials for sodium‐ion batteries is studied for the first time. The electrochemical results demonstrate that the ZnFe 2 O 4 anode experiences a series of conversion and alloying reactions for reversible sodium storage and exhibits high sodium storage capacity and excellent stability. It exhibits a reversible capacity as high as 350 mAh g −1 after 300 cycles at 100 mA g −1 , which is superior to other reported ZnO and ZnM x O y (M = Co, Sn, Ge) electrodes. The existence of the mesoporous structure is responsible for the excellent electrochemical properties of the microspheres, which not only enhances the electrochemical kinetics but also offers additional space to alleviate the strain associated with sodiation/desodiation.