Parallel Adsorption of Parts-per-Million Level Additives for Highly Efficient Aqueous Zinc-Ion Battery

• • 10 ppm (0.04 mM) PAN additive extends Zn||Zn symmetric cell lifespan to 1500 h at 2 mA cm−2 and 1 mAh cm−2, a 3-fold improvement over baseline, reducing battery replacement costs in grid storage. • • Zn||Cu half-cell with PAN achieves 99.91% Coulombic efficiency after 3500 cycles at 5 mA cm−2 and 1 mAh cm−2, minimizing capacity fade and enhancing round-trip energy efficiency. • • Zn||NH4V4O10 pouch cell retains 71.1% capacity after 250 cycles at 0.8 A g−1, demonstrating scalability for practical high-energy applications. • • PAN's parallel adsorption and chelation mechanism suppresses dendrite growth and parasitic reactions, enabling a 10-fold reduction in additive concentration compared to conventional 50–500 mM additives, lowering electrolyte cost and toxicity.