Synergistic polypyrrole coating and electrolyte engineering toward high-performance Zn-based batteries†

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