A common polar dye additive as corrosion inhibitor and leveling agent for stable aqueous zinc-ion batteries

The industrial application of zinc-ion batteries is restricted by irrepressible dendrite growth and side reactions that resulted from the surface heterogeneity of the commercial zinc electrode and the thermodynamic spontaneous corrosion in a weakly acidic aqueous electrolyte. Herein, a common polar dye, Procion Red MX-5b, with high polarity and asymmetric charge distribution is introduced into the zinc sulfate electrolyte, which can not only reconstruct the solvation configuration of Zn²⁺ and strengthen hydrogen bonding to reduce the reactivity of free H₂O but also homogenize interfacial electric field by its preferentially absorption on the zinc surface. The symmetric cell can cycle with a lower voltage hysteresis (78.4 mV) for 1120 times at 5 mA cm⁻² and Zn//NaV₃O₈·1.5H₂O full cell can be cycled over 1000 times with high capacity (average 170 mAh g⁻¹) at 4 A g⁻¹ in the compound electrolyte. This study provides a new perspective for additive engineering strategies of aqueous zinc-ion batteries.