Molecular Engineering of Polytriphenylamine: A Fluorinated Cathode for High‐Voltage, Ultrafast, and Stable Sodium‐Ion Batteries

Organic electrodes are promising candidates for sustainable battery materials owing to their tunable molecular structures, cost‐effectiveness, and use of earth‐abundant elements. However, the operating voltage of organic cathodes generally remains lower than that of their inorganic counterparts. Herein, we propose a molecular design strategy to increase the redox potential of nitrogen‐based conjugated polymers by fluorinating poly(triphenylamine) (PTPA). Using this approach, a new conjugated polymer, poly(pentafluorophenyl)diphenylamine (PFTPA), is developed as a high‐voltage p‐type cathode material for sodium‐ion batteries (SIBs). The introduction of pentafluorophenyl (PFP) groups modulates the electronic structure and minimizes structural reorganization during redox reactions, enabling fast and reversible anion storage. As a result, the PFTPA cathode delivers a specific capacity of 77 mAh g −1 at 1C with a high average discharge voltage of 3.75 V vs. Na/Na + as well as excellent rate capability, retaining 60.5% of its capacity even at an ultrahigh rate of 200 C. Moreover, the polymer exhibits outstanding cycling stability, maintaining stable operation over 10 000 cycles at 10 C. Owing to the combination of high‐voltage, fast kinetics, and long cycle life, PFTPA represents a promising redox‐active polymer for high‐performance and sustainable SIBs.