A carbonyl-rich porous organic polymer cathode for high-performance air self-charging aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) with air self-charging capability can meet urgent power supply needs in severe environments without external power supply as a self-powered system. To realize satisfactory self-charging capability, the performance of cathode materials is crucial. Herein, we synthesized a new porous organic polymer (PDBQ-POP) with carbonyl groups (C=O) as the cathode material of AZIBs. Due to PDBQ-POP having abundant active centers and porous structure, the coin-type and flexible Zn//PDBQ-POP AZIBs exhibit high energy densities of 140.9 Wh kg −1 and 10.7 mWh cm −3 , respectively, accompanied by excellent rate performance and the co-uptake/removal process of Zn 2+ and H + ions. Encouragingly, the electrical energy depleted flexible Zn//PDBQ-POP AZIBs can be recharged via the redox reaction between the discharged PDBQ-POP cathode and O 2 in air. Following 23 h of air exposure, the flexible Zn//PDBQ-POP battery exhibits a high discharge capacity of 176 mAh g −1 at 0.5 A g −1 , along with excellent rate capability (61 mAh g −1 at 20 A g −1 ) and higher cyclic stability of over 11 cycles in the air-charge/galvanostatic discharge process. Furthermore, it operates well in hybrid modes of chemical and/or constant current charging. Our work offers an attracting way for the construction of high-performance AZIBs with air self-charging function.