Porous Organic Polymers with Multiple p‐Type Redox‐Active Sites as Organic Cathode Materials for Lithium‐Ion Batteries with >3.5 V Output Voltage ^†

Comprehensive Summary Porous organic polymers (POPs) have shown great potential as organic cathode materials (OCMs) for advanced lithium‐ion batteries (LIBs). However, OCMs still face challenges such as insufficient output voltages. In this work, we report the design and synthesis of two dihydrophenazine‐based POPs (denoted as TPBPA‐DHP and PPT‐DHP) with multiple p‐type redox‐active sites. When employed as OCMs for LIBs, both TPBPA‐DHP and PPT‐DHP cathodes exhibit high voltage platform characteristics, achieving ultrahigh output voltages of 3.59 and 3.61 V, respectively, along with remarkable energy densities of 536.8 and 502.1 Wh·kg –1 . Benefiting from their highly crosslinked structures and robust skeletons, both POP cathodes exhibit long cycle stability, retaining 72.7% and 70.8% of their capacities after 1000 cycles at 0.5 A·g –1 . Ex situ FT‐IR spectra and EPR measurements were conducted to elucidate the redox mechanism involving anion interactions with p‐type redox‐active centers. Moreover, the PPT‐DHP//graphite full cell delivers a high average discharge capacity of 129.2 mAh·g –1 at 0.1 A·g –1 , retaining 76.9% of its initial capacity after 1000 cycles at 0.5 A·g –1 . This study provides valuable insights into the molecular design and synthesis of p‐type POPs for the next generation high‐voltage LIBs.