Synergistic enhancement of zinc ion storage performance by N atoms and ion additives

Abstract

The insertion of ion additives into electrolyte can effectively improve the electrochemical properties of energy storage devices by redox reaction. Besides, the doping of heteroatoms increase the defect sites at the edge of carbon materials (CMs), induce the reaction of Zn²⁺ with functional groups, thereby enhancing the capacity of carbon materials. Herein, the N doped carbon nanosheets with excellent surface area of 1318.2 m² g⁻¹ are prepared using glycine as nitrogen sources. The synergistic effect of the introduction of nitrogen into CMs and the addition of redox ion additives into electrolyte enhances the storage performance of zinc ions, resulting in intriguing specific capacity of 211.8 mAh g⁻¹, superior energy output of 177.5 Wh kg⁻¹ and outstanding cycle life with capacity decay of 0.000075 % per cycle in 1 M Zn(CF₃SO₃)₂/0.1 M ZnI₂ electrolyte. This work supplies a feasible method to enhance the zinc ion storage properties by doping of heteroatoms into CMs and introducing of ion additives into electrolyte.