Polyimide‐Linked Hexaazatriphenylene‐Based Porous Organic Polymer with Multiple Redox‐Active Sites as a High‐Capacity Organic Cathode for Lithium‐Ion Batteries
Arindam Mal, Jonathan Caroni, Asia Patriarchi, Olivera Lužanin, R. Ramos, Jan Bitenc, Manuel Melle‐Franco, Manuel Souto
Abstract
Abstract The development of high‐capacity, sustainable cathode materials remains a critical challenge in advancing lithium‐ion battery technologies for next‐generation energy storage. Organic electrode materials (OEMs) represent a promising alternative to conventional inorganic cathodes, owing to their composition from earth‐abundant elements and chemically tunable structures that enable high theoretical capacities. Herein, a polyimide‐linked porous organic polymer (HAT‐PTO) is reported to be synthesized via a straightforward hydrothermal reaction from redox‐active hexaazatriphenylene (HAT) and pyrene‐4,5,9,10‐tetraone (PTO) building blocks. The resulting HAT‐PTO framework incorporates multiple redox‐active C═O and C═N centers, delivering a high theoretical capacity of 484 mAh g −1 . To overcome limitations in electronic conductivity, hybrid materials are synthesized by in situ growth of HAT‐PTO on multiwalled pristine (CNT) and carboxyl‐functionalized carbon nanotubes (cCNT). Notably, the HAT‐PTO‐cCNT hybrid delivers a high capacity of 397 mAh g −1 at C/10, outstanding rate capability of 225 mAh g −1 at 20 C, and long‐term cycling stability, retaining 171 mAh g −1 after 6000 cycles at 2 C. Ex situ FT‐IR, supported by density functional theory (DFT) calculations, confirms the involvement of both HAT and PTO units in the charge storage mechanism. This work presents a molecular design strategy and scalable synthesis approach toward high‐performance organic cathodes, paving the way for durable, high‐rate lithium‐organic batteries.