Proton Self-Doped Polyaniline with High Electrochemical Activity for Aqueous Zinc-Ion Batteries

Abstract

Aqueous zinc-ion batteries are promising energy storage devices due to their low cost, good ionic conductivity, and high safety. Conductive polyaniline is a promising cathode because of its redox activity, but because the neutral electrolyte protonates only weakly, it displays limited electrochemical activity. A polyaniline cathode is developed with proton self-doping from manganese metal–organic frameworks (Mn–MOFs) that alleviates the deprotonation and electrochemical activity concerns arising during the charge/discharge process. The MOFs carboxyl group provides protons to prevent deprotonation and allows the polyaniline to reach a high zinc storage redox activity. The proton self-doped polyaniline cathode has a superior specific capacity (273 mAh g⁻¹ at 0.5 A g⁻¹), a high rate property (154 mAh g⁻¹ at 20 A g⁻¹), and excellent cyclability retention (87% over 4000 cycles at 15 A g⁻¹). This research provides fresh insight into the development of innovative polymers as cathode materials for high-performance AZIBs.