Electrolyte Additive l‑Lysine Stabilizes\nthe Zinc Electrode in Aqueous Zinc Batteries for Long Cycling Performance

Rechargeable aqueous Zn-ion batteries (AZIBs) have been\nrecognized\nas competitive devices for large-scale energy storage due to their\ncharacteristics of low cost, safe operation, and environmental friendliness.\nNevertheless, their practical applications are greatly limited by\n zinc dendrite growth and side reactions occurring at the anode/electrolyte\ninterface. Herein, we propose an effective and simple electrolyte\nengineering strategy, which is the introduction of l-lysine\nadditive containing two amino groups and one carboxyl group into a\nZnSO<sub>4</sub> electrolyte to achieve stable and reversible Zn depositions.\nTheoretical calculations and experimental results reveal that the l-lysine can adsorb on the Zn anode surface due to the strong\ncoordination effects between amino groups and Zn metal (Zn–N\nbinding) and induce the reduction of ZnSO<sub>4</sub> into inorganic\nZnS, which can not only prevent interfacial side reactions but also\nregulate interfacial electric field on the zinc electrode surface\nto guide uniform Zn<sup>2+</sup> electrodeposition to inhibit zinc\ndendrites. Consequently, the l-lysine additive in the electrolyte\nenables Zn||Zn symmetric cells to achieve an ultralong stable cycling\nup to 2400 h at 1 mA cm<sup>–2</sup> with a low polarization\nof only about 16 mV and Zn||Cu asymmetric cells to obtain a high average\nCoulombic efficiency of 99.80% after stably cycling for more than\n2000 h at 2 mA cm<sup>–2</sup> (1 mAh cm<sup>–2</sup>). In addition, the Zn||MnO<sub>2</sub>@CNT full cell in an l-lysine-containing electrolyte also exhibits good cycling performance.\nThis study offers a new perspective on multifunctional electrolyte\nadditive for achieving highly reversible Zn metal anodes in AZIBs.