A High-Voltage Aqueous Rechargeable Zinc-Polyaniline Hybrid Battery Achieved by Decoupling Alkali–Acid Electrolyte

Aqueous Zinc–polyaniline (Zn-PANI) batteries have attracted attention due to their high safety and low cost but they suffer from the limited water electrochemical window (1.23 V), fast capacitance decay derived from the structural instability of PANI, and poor electroactivity of PANI in low acidic electrolytes due to its de-protonation. Here, we firstly report a decoupling design of acid-alkaline electrolyte to maximize the electrochemical window of the electrolyte and optimize the redox chemistry of both PANI cathode and Zn anode. The PANI electrode delivers higher stability in H 2 SO 4 electrolytes than the conventional Zn 2+ neutral or weakly acidic electrolytes. The optimized electrolyte-decoupling Zn-PANI (EDZPB) battery exhibits an expanded electrochemical stability window over 2 V, a high capacity of 213.3 mAh g −1 at 0.1 A g −1 , and high cycling life stability (only 6.8% loss after 3000 cycles), showing great potential of the design for applications in large-scale energy storage.