Synergistic Polypyrrole Coating and Electrolyte Engineering toward High-Performance Zn-Based Batteries

Abstract

Aqueous zinc-ion batteries (ZIBs) are hindered by anode issues including dendrite growth, hydrogen evolution, and passivation. Herein, we propose a polypyrrole (PPy) combined with citric acid (CA) and sodium sulfate (Na2SO4) additives to regulate Zn2+ reduction kinetic. The modified anode enables a symmetric cell to achieve stable cycling over 400 h (1 mA cm⁻², 1 mAh cm⁻²) with low polarization voltage (45 mV). Furthermore, the assembled full cell with α-MnO₂ cathodes retains a capacity of 140 mAh g⁻¹ after 2000 cycles, demonstrating practical viability.