Regulating Steric Hindrance in Redox‐Active Porous Organic Frameworks Achieves Enhanced Sodium Storage Performance

Abstract The development of novel redox‐active polymers for sustainable sodium ion batteries (SIBs) has captured growing attention, but battery performance has been significantly limited by poor reversible specific capacities, where the majority of aromatic C6‐benzene linkages are redox inactive. Here, a simple, yet efficient approach to improve sodium (Na) storage on these C6‐benzene rings within a porous polymeric framework by rationally regulating their steric hindrance is reported. Decreasing intrinsic hindrance affords a significant improvement in redox reaction kinetics within the porous architecture, thereby facilitating the acceptance of Na ions on these functionalized benzene rings and boosting the SIB performance. As a result, the modulate porous framework exhibits an exceptional battery capacity of 376 mAh g⁻¹ after 1000 cycles at 1.0 A g⁻¹, which is ≈1.5 times larger than that of the pristine framework. Furthermore, the performance can reach as high as 510 mAh g⁻¹ at 0.1 A g⁻¹, comparable to that of the best‐performing polymeric electrodes. The simple modulation approach not only enables Na storage modulation on functionalized C6‐benzene rings, but also simultaneously provides a means to extend the understanding of the structure‐property relationship and facilitate new possibilities for organic SIBs.