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.