Robust Fully Aromatic-Conjugated Covalent Organic Frameworks for High- Performance and Wide-Temperature-Range...

Synthesizing covalent organic frameworks (COFs) with robustness and temperature adaptability for advanced potassium-ion battery (PIB) cathodes remains challenging. Here, robust, fully aromatic-conjugated COFs with abundant redox-active sites are reported, synthesized through condensation of 2,3,7,8-tetraaminophenazine-1,4,6,9-tetraone and hexaketocyclohexane octahydrate (HATN-TAPT COF). The porous and flexible architecture accommodates volumetric changes during potassiation/depotassiation processes. Additionally, optimized flame-retardant electrolytes enhance PIB safety. As a cathode, it demonstrates an unprecedented capacity of 455 mAh g^-1 at 0.1 A g^-1, with a median voltage of 1.89 V, yielding an energy density of 860 Wh kg^-1 _cathode. The material also exhibits excellent rate capacity (209 mAh g^-1 at 10.0 A g^-1), delivering an exceptional power density of 18 900 W kg^-1 _cathode. The aromatic-conjugated structure provides superb structural stability, with remarkable cycling performance of 235 mAh g^-1 at 1.0 A g^-1 after 5000 cycles and a low decay rate of 0.0045% per cycle, superior to the best-reported organic PIB cathodes. More importantly, the K//HATN-TAPT COF cell exhibits all-weather working potential, demonstrating wide-temperature adaptability from -30 °C (355 mAh g^-1 at 0.02 A g^-1) to 60 °C (387 mAh g^-1 at 0.5 A g^-1), making it highly promising for extreme environments such as space, high-altitude regions, and tropical zones.