In‐situ Electropolymerized Bipolar Organic Cathode Material for High‐Voltage Sodium Dual‐Ion Batteries with Long‐Cycle Performances

Comprehensive Summary Organic electrode materials offer advantages such as structural tunability and high redox reversibility. However, they still face challenges in pursuing long‐term cycling stability and high operating voltage. To address these challenges, a donor‐acceptor monomer (TPA‐PQ) integrating phenanthrenequinone (n‐type) and triphenylamine (p‐type) units is synthesized, which then undergoes in‐situ electropolymerization to form a bipolar cathode material pTPA‐PQ for SIBs. The in‐situ electropolymerization significantly enhances structural stability and cycle performances. As a result, the pTPA‐PQ electrode exhibits a high average voltage of 3.15 V, as well as a remarkable energy density of 441 Wh·kg –1 . Notably, the average voltage achieved represents one of the highest values reported in bipolar organic electrode materials. More importantly, the pTPA‐PQ electrode demonstrates excellent stability even after 10,000 cycles in a half‐cell, with an average capacity decay rate of only 0.0032% per cycle. Furthermore, symmetric all‐organic full cells based on pTPA‐PQ achieve a high energy density of 173.8 Wh·kg –1 and maintain stable cycling over 2,000 cycles even at a high C‐rate of 6 C. This work provides a feasible pathway for developing high‐performance organic electrode materials for sodium‐ion batteries.