F, O co-doped porous hard carbon from conjugated microporous polymer for efficient lithium storage

Hard carbon is a promising alternative to conventional graphite due to its adjustable chemical composition and amorphous structure. Herein, F, O co-doped hard carbon (FOPHC) is constructed from F-containing conjugated microporous polymers, which is synthesized from 1,3,5-triethynylbenzene and 1,4-dibromotetrafluorobenzene. BET, XPS, and EDS analyses demonstrate that FOPHC is a nanoparticle with a hierarchical pore structure and F, O co-doping. When evaluated as an anode for LIBs, the FOPHC delivers an impressive 781 mA h g−1 at 0.1 A/g and 420 mA h g−1 at 0.6 A/g after 300 cycles. Kinetic calculation reveals that the dominated pseudocapacitance contribution of Li-storage in FOPHC (67.5 %, at 1.0 mV/s), attributed to the well-developed hierarchical pore structure and abundant defect sites. This work provides original insights for the microstructure regulation and design of hard carbon.