A polyaniline surface-modified Prussian blue analogue cathode for flexible aqueous Zn-ion batteries.

Aqueous Zn-ion batteries have gained popularity due to their low cost and high safety, but their low energy density limits their application scenarios. Although the Prussian blue analogue (PBA) has the characteristics of high redox potential, the poor capacity and cycling performance restrict its further development. Here, we propose a modification strategy of a polyaniline (PANI) coating on zinc ferricyanide (ZnHCF). The PANI coating inhibits the dissolution of ZnHCF and enables the Zn-ion battery to present two long-flat discharge voltage platforms as well as a high capacity of 150 mA h g -1 , which provides a new idea for the development of high-performance PBA battery materials. Meanwhile, owing to the spring-like structure, the battery has a high stretchability of 600% and maintains stable electrochemical properties during stretching.