Polarized Metal Organic Framework Nanoreactors for Rechargeable Sodium–Chlorine Batteries

Rechargeable sodium–chlorine (Na–Cl2) batteries have attracted attention for next-generation energy storage. However, their application is hindered by poor cycling stability, primarily caused by sluggish reaction kinetics and uneven NaCl nucleation. Herein, we prepared a series of polarized metal organic frameworks (MOFs) and verified that polar groups anchored on the penetrated porous skeletons can act as confined nanoreactors, enhancing the Cl–/Na+ adsorption capability and simultaneously repulsing the formed Cl2, finally boosting the uniform deposition/exfoliation of NaCl nanocrystals and reversible reaction between NaCl and Cl2. The Na–Cl2@UiO-66-SO3H battery demonstrates a polarization of 0.27 V, along with cycling for 600 cycles at 10,000 mA g–1, and even operates at a current density of 20,000 mA g–1. Moreover, this sodium–chlorine battery shows performance at low temperature, increased areal capacity, and capacity scaling in large-format pouch cells.