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

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.