Polyhydroxylated Organic Molecular Additives for Durable Aqueous Zinc Battery

Abstract

AbstractThe large‐scale deployment of aqueous Zn‐ion batteries is hindered by Zn anode instability including surface corrosion, hydrogen gas evolution, and irregular Zn deposition. To tackle these challenges, a polyhydroxylated organic molecular additive, trehalose, is incorporated to refine the solvation structure and promote planar Zn deposition. Within solvation structure regions involving trehalose, the hydroxy groups participate in the reconstruction of hydrogen bond networks, which increases the overpotential for water decomposition reaction. Moreover, at the Zn metal–molecule interface, the chemisorption of trehalose onto the surface of the zinc anode enhances corrosion resistance and facilitates the deposition of zinc in a planar manner. The optimized electrolyte significantly improves Zn striping/plating reversibility and maintains stable potentials over 1600 h at 5 mA cm−2 with a cutoff capacity of 1 mA h cm−2 in symmetric cells. When combined with the MnO2 cathode, the assembled coin cell retains ≈89% of its capacity after 1000 cycles. This organic molecule additive, emphasizing the role of polyhydroxylated organic molecules in fine‐tuning solvation structures and anode/electrolyte interfaces, holds promise for enhancing various aqueous metal batteries.