Phenazine-based organic cathode for aqueous zinc secondary batteries

Aqueous Zn-ion secondary batteries (AZSBs) with excellent electrochemical performance using small organic phenazine (PNZ) as cathode material are achieved. The PNZ-based battery can display a specific capacity of 232 mAh g−1 when cycled at 20 mA g−1. Good rate performance and long cycle life reveal that small organic molecules like the PNZ with less hydrophilic groups on its peripheral positions show excellent insolubility in water and can be a potential electrode material for AZSBs. The redox kinetics property research reveals that the Zn ion insertion/extraction reactions are predominantly controlled by the diffusion process. The investigation of the ex situ fourier transform infrared (FTIR), ultraviolet–visible (UV–Vis) spectra and X-ray photoelectron spectroscopy (XPS) prove that the CN bonds are zinc-binding centers/sites in the phenazine.