Perinone with fast proton insertion chemistry for durable aqueous zinc battery

Abstract

Organic materials are highly promising for application in aqueous zinc-ion batteries (ZIBs) due to environmental friendliness and structural flexibility. However, high solubility and poor conductivity of organic materials are two key challenges that lead to unsatisfactory battery performance. Herein, polycyclic perinone molecule is proposed as a robust cathode material for ZIBs because of its abundant redox-active groups and high-coplanar, extensive π-conjugation based on the aromatic skeleton. The unique molecule structure and low band gap endow perinone with high redox activity and excellent cycling stability. The perinone electrode delivers a specific capacity of 118 mAh/g under a two-electron redox process. Moreover, high capacity retention of 100 % is achieved after long-term cycling as well as high rate capability. The majority of capacity at 0.1 A/g is well preserved even at 10 A/g, which is superior to conventional organic materials. Advanced characterizations reveal that rather than Zn²⁺, hydrated proton (H⁺·(H₂O)_n) and pure H⁺ are inserted into perinone molecules in a staging manner. Our work provides new insights into molecular structure design for durable and high-rate energy storage.