Nitrogen-Centered Redox Active Polymers with Extended π-Conjugated Structures for High-Performance Potassium Dual-Ion Batteries

Nitrogen-containing p-type organic electrodes have demonstrated significant promise for constructing high-voltage dual-ion batteries. However, few examples of high-performance p-type organic electrodes have been successfully applied in potassium dual-ion batteries. In this work, we develop a novel p-type polymer cathode, poly[5-(9-(4-tert-butylphenyl)-9H-carbazol-3-yl)-5,10-dihydrophenazine] (p-TPCDP), designed as a high-potential cathode material for potassium dual-ion batteries. The redox-active nitrogen centers in p-TPCDP enable anion-storage mechanisms and provide a maximum theoretical specific capacity of 112 mAh g–1 based on two-electron transfer processes. By coupling 9-(4-(tert-butyl)phenyl)-9H-carbazole (TPC) and 5,10-dihydrophenazine (DPZ) moieties to construct the polymer framework, p-TPCDP exhibits an extended π-conjugated structure that facilitates efficient electron delocalization and rapid ion transport kinetics. Characterizations further confirm that p-TPCDP can stably and reversibly store PF6– anions for charge compensation at high potentials (>3 V vs K-metal anodes). In half-cell tests, p-TPCDP delivers a highly stable specific capacity of 114 mAh g–1 with an average discharge potential of 3.53 V at 100 mA g–1 (corresponding to an energy density of 402 Wh kg–1), which also maintains 94% capacity retention after 1300 cycles at 1 A g–1. Notably, the p-TPCDP exhibits superior rate capability, retaining 92 mAh g–1 even at an ultrahigh rate of 50C. Furthermore, when assembled into K-based dual-ion full batteries (PDIBs) with a graphite anode and p-TPCDP cathode, the battery demonstrates a high average voltage of 2.82 V, a peak discharge capacity of 102 mAh g–1, and an energy density of 288 Wh kg–1 while maintaining stable cycling performance over 300 cycles.