Binary Additive in Millimolar Concentration for Long Cycling Life of Zinc‐Ion Batteries

Abstract The reversibility of stripping and plating of the Zinc anode is one of the major bottlenecks of Zinc‐Ion batteries. In this publication, we propose a millimolar concentration additive blend that shall promote homogeneous Zinc plating with suppressed dendrite formation and reduce the influence of water‐splitting reactions. We use 5.5 mM sodium dodecyl benzene sulfonate (SDBS). SDBS adsorbs at the Zinc electrode and forms a protection layer that promotes homogenous crystallization. 4.5 mM Ethylenediamine‐tetraacetate (EDTA) is meant to hinder water splitting. It reduces the activity of water at the Zinc surface. Both additives together exhibit a synergistic effect, resulting in higher performance compared to cells with either additive alone. We propose a handover of the Zinc ions between the EDTA in solution and the SDBS layer as a reason for this effect. Our Zn//Zn symmetric cell tests ran for 3850 hours and 1925 cycles at 1 mA/cm 2 and 1 mAh/cm 2 . In the end, Zinc‐MnO 2 full cells were tested, showing a capacity retention of 52 % over 400 cycles.