Hierarchical Hollow Prussian Blue Rods Synthesized via Self‐Sacrifice Template as Cathode for High Performance Sodium Ion Battery

Abstract

In this work, a facile strategy is proposed to synthesize hierarchical hollow rod‐like Mn‐doped Prussian blue (R‐PB) using MnO ₂ nanosheets as a self‐sacrifice template. The as prepared R‐PB with low contents of vacancies and coordinated water, and high content of sodium, exhibits appealing electrochemical performance as a cathode for sodium ion batteries (SIBs) achieving a high discharge capacity of 117.3 mAh g ⁻¹ and a capacity retention of 98.5% after 200 cycles at 1 C. Moreover, the specific capacity reaches 111.5 mAh g ⁻¹ at 5 C with a Coulombic efficiency (CE) of 93.8%. The high capacity, superior cycling stability, and enhanced kinetics of Na ⁺ migration of R‐PB are attributed to the positive effect of doped Mn ions and the hierarchical hollow rod‐like structure. The doped Mn ions in R‐PB activate the redox of Fe ^LS(C) in the high voltage region to reach a high capacity. The unique hierarchical hollow rod‐like structure provides a buffer space for the volume change during the insertion/extraction of sodium ions, enlarges the contact area between the electrode materials and electrolyte, and enhances the apparent diffusion coefficient of sodium ions in electrode materials.