A redox-active conjugated microporous polymer cathode for high-performance lithium/potassium-organic batteries

Organic redox-active materials have emerged as a class of electrode materials for rechargeable batteries due to their high redox activity, low cost, structure diversity and flexibility. However, the high solubility of organic small molecules in organic electrolytes commonly leads to the fast capacity decay with cycling. Herein, we report a redox-active conjugated microporous polymer of poly(pyrene-co-anthraquinone) (PyAq) cathode material consisting of pyrene and anthraquinone units. Benefiting from the highly cross-linked polymer structure with insoluble nature in organic electrolytes, the high surface area and the plentiful redox-active carbonyl groups, the PyAq cathode demonstrates outstanding electrochemical performances for both lithium-ion batteries (LIBs) and potassium-ion batteries (KIBs). Specifically, the PyAq cathode for LIBs delivers a high reversible capacity of 169 mAh g−1 at the current density of 20 mA g−1, a high rate capability (142 mAh g−1 at 1000 mA g−1) and an excellent cycling stability for 4000 cycles. Additionally, the PyAq cathode for KIBs also exhibits a high reversible capacity of 143 mAh g−1 with a long cycling life over 800 cycles. The excellent electrochemical performance demonstrates that the newly developed PyAq could be an attractive cathode material for the advanced energy storage technologies.