Extending π-Conjugation and Integrating Multi-Redox Centers into One Molecule for High-Capacity Organic Cathodes

Structural diversity, designability, and eco-friendliness make organic electrode materials appealing for next-generation rechargeable batteries. However, most of them show low specific capacity and poor cycling stability, which limit their further application. To develop high-capacity imide-based cathode materials, three C₃ -symmetric triimides were designed. Systematic comparisons of these triimides as cathode materials revealed that extending π-conjugation and incorporating multiple redox centers improved the cell performance in terms of specific capacity and cycling stability. In particular, a nitrogen-rich heteroaromatic hexaazatrinaphthylene triimide (HATNTI-Pr) with multiple active sites (imide and pyrazine) exhibited high specific capacity. Hybridized with graphene sheets, a HATNTI-Pr-based binder-free cathode delivered a high practical capacity (317 mAh g^-1 at 0.1 C), excellent cycling stability (80 % retention after 100 cycles), and considerable rate performance (75 mAh g^-1 at 5 C). The energy storage mechanism of HATNTI-Pr with up to nine Li⁺ storage ability was investigated.