Modification For Anode Protection Layer Of Aqueous Zinc Ion Battery And Electrochemical Performance

Aqueous Zn ion battery has been widely investigated in recently due to the high theoretical specific capacity,low redox potential and environmental friendliness of zinc metal anode.However,the problems of dendrite growth,passivation,corrosion and hydrogen evolution reaction in the cycle of zinc ion batteries lead to the reduction of their cycle life and coulombic efficiency,which seriously hinder the large-scale application of zinc ion batteries.Therefore,this paper induces the uniform stripping/plating of zinc ions during the charge/discharge process by constructing an artificial protective layer on the surface of zinc foil to effectively improve the cycle life and coulombic efficiency of aqueous zinc ion batteries.Finally,full cells were assembled with manganese-based oxide cathode materials to evaluate their electrochemical performance.The specific research work is as follows:First,a liquid-phase reaction method was used to grow in situ a protective layer with a three-dimensional structure of ZIF-8（Zn@ZIF-8 anode）using zinc foil as a substrate.Thanks to the large specific surface area and good wettability of ZIF-8,the Zn²⁺flux is effectively regulated to induce uniform zinc deposition on the Zn foil surface.It has a long cycle life of over 1100 h in symmetric cell tests at a current density of 1 m A cm^-2 and a capacity density of 1 m Ah cm^-2.The full cell assembled with Zn@ZIF-8 and Al intercalatedδ-Mn O₂@r GO（δ-GAMO）has a discharge specific capacity of 138 m Ah g^-1 after 500 cycles at a current density of 1000 m A g^-1 higher than that of the Zn foil battery,which has excellent cycling stability.Secondly,in order to further modulate the plating/stripping behavior of Zn on the Zn foil surface,a simple anodic etching method was used to modify the Zn foil surface to prepare a porous Zn P protective layer（Zn@Zn P anode）with a uniform and dense texture.The Zn P protective layer grows uniformly on the surface of the zinc foil,effectively avoiding contact between the zinc foil and the electrolyte and weakening the occurrence of side reactions,thus inducing uniform zinc deposition and inhibiting the growth of dendrites.Electrochemical tests showed that the porous structure of the Zn@Zn P cathode had stable cycling performance(cycle life improved from 180 h to 2100 h at 5 m A cm^-2).In the full batteries test assembled withδ-GAMO,the discharge specific capacity of the cathode material was 138 m Ah g^-1 after 500 cycles at a current density of 1000 m A g^-1.The analysis of the Zn P deposition behavior showed that the Zn P protective layer strongly enhanced the wettability of the Zn@Zn P cathode with the Zn SO₄ electrolyte,which The abundant Zn²⁺nucleation sites provided successfully induced the uniform deposition of Zn and effectively inhibited the growth of Zn dendrites.