Regulating uniform nucleation of ZnS enables low-polarized and high stable aqueous Zn–S batteries

Sulfur-based cathode materials can greatly improve the overall energy density of the aqueous zinc ion batteries. However, it suffers from uneven accumulated discharge products of ZnS, which retard the conversion to S during charge process. Herein, we report a regulation strategy for uniform ZnS nucleation by introducing PEG-400 additive into 1 M Zn(CH3COO)2 electrolyte to form a modified solvation structure. Uniform and small ZnS with the average diameter of 180 nm can be formed, which is favorable for the conversion from ZnS to S. The S@CNTs cathode using such an aqueous electrolyte exhibits a lower voltage hysteresis of 0.47 V, high capacity of 1116 mAh/g at the current density of 0.1 A/g, and a good rate capacity of 774 mAh/g at 1 A/g. Furthermore, the addition of PEG can also improve the stability of Zn anode; as a result, we achieve a Zn–S full cell with a low overpotential performance and stable reversibility.