Dihydrophenazine‐Based Copolymers as Promising Cathode Materials for Dual‐Ion Batteries

Herein, two novel copolymers of dihydrophenazine with diphenylamine (PDPAPZ) and phenothiazine (PPTZPZ) are synthesized and investigated as cathode materials for dual‐ion batteries. Both polymers demonstrate high average discharge potentials (3.5–3.6 V) in lithium cells. The PDPAPZ//Li cells demonstrate impressive rate capability: specific capacities of 101 and 82 mAh g−1 are reached under galvanostatic charging and discharging at the high current densities of 5 and 20 A g−1, respectively. The capacity retention of 86% and 34% after 100 and 25 000 cycles, respectively, features decent operational stability of the batteries. Furthermore, an encouraging energy density of 398 Wh kg−1 is achieved in potassium PDPAPZ//K cells. The obtained values place PDPAPZ on par with the best organic cathode materials for fast lithium and potassium batteries. Two novel dihydrophenazine‐based copolymers are synthesized and explored as cathode materials in dual‐ion batteries. The best‐performing PDPAPZ cathodes deliver decent specific capacities, high discharge potentials, good capacity retention, and outstanding rate capability, thus paving a way to designing ultrafast organic batteries.