Bipolar porous organic polymers with densely distributed redox-active centers as organic cathodes for fast-charging and long-life lithium-ion batteries
摘要
Organic cathode materials (OCMs) with high capacity, fast-charging ability, and long-term cycling stability are crucial for advancing sustainable and high-performance lithium-ion batteries (LIBs). Herein, we report two bipolar porous organic polymers (POPs) featuring densely distributed redox-active centers and arylamine linkage as high-performance OCMs (denoted as HATN-3AQ and HATN-3AB). The deliberate incorporation of multiple redox-active sites and arylamine moieties enhances electronic delocalization and enables efficient bipolar redox activity. Meanwhile, the porous framework promotes efficient electrolyte penetration, accelerates rapid Li+ transport, and exposes a large number of redox-active sites. Benefiting from these synergistic structural and electronic advantages, the HATN-3AQ cathode delivers a high reversible capacity of 219.5 mAh g−1 at 0.1 A g−1, together with an exceptional rate capability of 136.9 mAh g−1 at a high current density of 20 A g−1 (≈68 C), enabling the fast-charging of an energy output of 249.5 Wh kg−1 within 1 min. Moreover, it exhibits outstanding cycling durability, retaining 82.1 mAh g−1 after 4000 cycles at 10 A g−1. DFT calculations in combination with comprehensive ex situ characterizations were performed to further elucidate the dual-ion storage mechanism for both bipolar POPs during the charge-discharge process. This study establishes a general molecular-engineering approach for constructing OCMs with high capacity, ultrafast charging capability, and long cycle life, and highlights bipolar POPs as a promising and versatile platform for sustainable LIBs.