A Sodium-Ion Full-Cell Battery with Two Individual Covalent Organic Frameworks (COFs) as the Cathode and Anode

We present an organic sodium-ion full-cell battery with two redox-active covalent organic frameworks (COFs, CityU-36 and CityU-44) serving as the anode and cathode, respectively. The cathode COF (CityU-44) incorporates a nitro group, delivering a high output voltage, and the anode COF (CityU-36) is functionalized with imidazole units and carbonyl units to maximize the energy density. The integration of the two COF electrodes in a battery cell delivers a reversible capacity of 187 mAh g –1 with 83% retention of the initial capacity after 800 cycles. This work demonstrates that an all-COF-based sodium-ion battery (SIB) with a rational design strategy is a promising candidate for sustainable energy storage.