Conjugated Microporous Polymers with Tunable Electronic Structure for High Performance Potassium-Ion Batteries.

Conjugated microporous polymers (CMPs) with π-conjugated skeletons show great potential as energy storage materials due to their porous structure and tunable redox nature. However, CMPs and the structure-performance relationship have not been reported for potassium-ion batteries (KIBs). Here, we report structure-engineered CMP anodes with tunable electronic structures for high performance KIBs. The results demonstrate that electronic structure of the CMPs play an important role in enhancing potassium storage capability, including the lowest unoccupied molecular orbital (LUMO) distribution, LUMO energy level and band gap. These can be finely tuned by synthetic control. It was revealed that the poly(pyrene-co-benzothiadizole) (PyBT) with optimized structure can deliver a high reversible capacity of 428 mAh g1 and an excellent cycling stability over 500 cycles. Our findings provide a fundamental understanding for designing CMP anode materials for high performance potassium-organic energy storage devices.