Manipulating Polymer Configuration to Accelerate Cation Intercalation Kinetics for High-Performance Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) with safety and cost superiority are becoming promising for energy storage; meanwhile, organic electrodes are attracting considerable interest. The development of organic ZIBs lies in the solution of challenging issues on impeded Zn2+ interfacial diffusion and the corresponding sluggish reaction kinetics. Herein, triquinoxalinylene (3Q) based homopolymer (P3Q) and triazine-linked 3Q polymer (P3Q-t) with enlarged conjugated planes are designed and prepared to reveal the impact of molecular configuration on Zn2+ transfer and coordination dynamics. Their ZIB performance and ion intercalation mechanism are systematically investigated by structural characterization, electrochemical measurement, and theoretical calculation. Specifically, P3Q shows interactions with both Zn2+ and H+, while P3Q-t is discovered to selectively coordinate only with Zn2+. Moreover, P3Q-t exhibits high conjugated planarity and electronegative fused-rings pathways due to both intermolecular and intramolecular effects, leading to faster reaction dynamics and low Zn2+ transfer resistance. P3Q-t affords a high capacity of 237 mAh g(-1) at 0.3 A g(-1). More importantly, such capacity can be retained for 45% at 15 A g(-1) and an average 81% of capacity retention is achieved over 1500 cycles.