Janus Dione-Based Conjugated Covalent Organic Frameworks with High Conductivity as Superior Cathode Materials.

The development of conductive covalent organic frameworks (COFs) with high stability is desirable for the practical applications in optoelectronics and energy storage. Herein, we developed a new kind of Janus dione-based COF, which is fully sp carbon-conjugated through the connection by olefin units. The electrical conductivity and carrier mobility reached up to 10 S cm and 7.8 cm V s, respectively. In addition, these COFs are strongly robust against various harsh conditions. The well-ordered two-dimensional crystalline structures, excellent porosity, high conductivity, and abundant redox-active carbonyl units render these COFs serviceable as high-performance cathode materials in lithium-ion batteries. It is worth noting that TFPPy-ICTO-COF exhibits a capacity of up to 338 mAh g at a discharge rate of 0.1 C, which sets a new capacity record among COF-based lithium-ion batteries. Its capacity retention was as high as 100% even after 1000 cycles, demonstrating the remarkable stability of these Janus dione-based COF materials. This work not only expands the diversity of olefin-linked COFs but also makes a new breakthrough in energy storage.