Dual‐Bipolar Conjugated Organic Polymer Cathode Enabling Ultra‐Stable 10 000‐Cycle Organic Lithium and Sodium Batteries

Abstract

Organic molecules are potential electrode materials for various rechargeable batteries owing to their designable molecular structures and renewable resources; however, their poor electronic conductivity and high solubility in electrolytes limit their electrochemical performance. These challenges can be addressed by constructing conjugated organic polymers (COPs). Herein, a dual‐bipolar centers COP is reported via polymerization of 5,15‐bis(4‐cyanophenyl) porphyrin (H2BCPP) using triazine linker (H2BCPP‐COP) and evaluate its performance as a cathode for both lithium and sodium batteries. The electrochemical performance of H2BCPP‐COP is significantly improved compared with H2BCPP in both systems, exhibiting high capacity, outstanding rate capability, and excellent cycling stability. Notably, in organic lithium batteries (OLBs), H2BCPP‐COP achieves a capacity of 121 mAh g−1 over 10 000 cycles with 89% capacity retention of maximum capacity at 2.0 A g−1 at room temperature, while maintaining stable operation across a wide temperature range (−20–50 °C). Even higher capacities are observed in organic sodium batteries (OSBs), highlighting their versatility. In/ex situ spectroscopic analyses and theoretical simulations reveal that the exceptional performance arises from the highly stable COP backbone and the alternating interaction of cations and anions with the dual‐bipolar active sites (C─N/C═N) in the porphyrin and triazine units.