Ordered Macroporous Prussian Blue Analogues for Rechargeable Na‐Cl 2 Batteries

ABSTRACT Rechargeable Na‐Cl 2 batteries have emerged as a promising alternative and supplement for lithium‐ion batteries due to their ultra‐high energy density. Nevertheless, developing satisfactory cathode materials to facilitate the complex solid, liquid, and gas three‐phase conversion process during charge‐discharge cycling remains a significant challenge. Herein, we propose a three‐dimensional ordered macroporous Prussian blue analog (3DOM PBA) fabricated via a stepwise vacuum impregnation template strategy, which can serve as an ideal cathode material for rechargeable Na‐Cl 2 batteries. The hierarchically ordered porous structure arranging from micropores to macropores can provide appropriated channels for ions transfer, Cl 2 storage, and NaCl crystal deposition. Moreover, customizable metal site doping not only optimize the electronic and ionic conductivity but also provide efficient adsorption and in‐situ catalytic conversion sites for Cl 2 /Cl − , thereby effectively increasing the reversible reaction kinetics and long‐term cycling stability. As a result, the assembled Na‐Cl 2 battery delivers a reversible capacity of 2000 mAh g − 1 and stable cycling life of 2500 cycles at 15 000 mA g − 1 , which can still maintain reversible charge‐discharge behavior even at 30 000 mA g − 1 , much superior to the reported results. This study provides new insights for developing high‐performance electrode materials for rechargeable Na‐Cl 2 batteries.