Construction Of Electrode Materials For Zinc Ion Battery And Study On Zinc Storage Mechanism

As a newly developed energy storage system,aqueous zinc ion battery have attracted much attention of researchers.It has the characteristics of high theoretical capacity,low redox potential,and high safety.Metal zinc is a widely used anode for zinc ion battery.However,the problems of dendrites,corrosion,and hydrogen evolution that metal zinc anode face limit the cycle stability and life.To alleviate these problems,a strategy of constructing surface protective layer is designed to optimize zinc anode.Constructing surface protective layer is an effective strategy to suppress dendrites,which can provide reference for the development of zinc anode and other metal anode.The hydrophilic silica aerogel was first used for protective layer of zinc anode.The porous coating improves wettability of zinc anode to electrolyte,and makes the flux of zinc ions more uniform.The restriction effect of coating helps to obtain a uniform and stable deposition layer on the surface of zinc foil.The full cell assembled with aerogel coated anode has a discharge capacity of 108.3 m Ah g^-1 after 500 cycles of 600 m A g^-1,88.0 m Ah g^-1 higher than that of bare zinc.After cycling,the coating still maintains original porous structure and is tightly combined with zinc foil without obvious dendrites.Theγ-aluminum oxide was applied to protective layer of zinc anode,and the influence of different thicknesses is explored.Thick coating may reduce migration speed of zinc ions,thin coating may not be effective in preventing dendrites and corrosion.Zinc foil with a coating thickness of 15μm exhibits the best electrochemical performance.The symmetrical cell can stably cycled for 500 h at 0.4 m A·cm^-2.At rate current of 1000 m A g^-1,full cell(118.5 m Ah g^-1)deliver higher capacity than bare zinc cell(46.2 m Ah g^-1).Hafnium dioxide was used for protective layer of zinc anode.Porous coating guides uniform deposition of zinc ions,restricts growth of zinc deposition layer in a limited area,and suppress formation of dendrites.This helps to obtain a stable zinc anode.The voltage hysteresis of symmetrical cell with hafnium dioxide coated zinc（68 m V）is lower than that of bare zinc（82 m V）.The nucleation and growth of zinc are more uniform.Figure 47;Table 2;Reference 85...