Electrolyte Design And Interfacial Electrochemical Behavior For Aqueous Zinc Ion Battery

Aqueous zinc ion batteries are promising to be employed in the large-scale energy storage system due to their exceptional safety,high theoretical specific energy capacity,low cost,etc.Unfortunately,zinc dendrites will gradually emerge during cycling as well as the hydrogen evolution and corrosion that inevitably reduce the utilization rate of zinc anode and are likely to boost the uncontrolled growth of zinc dendrites.This will cause membrane puncture and battery failure ultimately,which seriously hinders the commercialization process of aqueous zinc ion batteries.In this dissertation,a series of optimized electrolytes have been developed that are able to effectively suppress zinc dendrites and side effects.Additionally,their working mechanisms have been precisely clarified via focusing on the interface between a zinc anode and an electrolyte.The main research works are shown as follows:（1）Introducing the high-valence cation into an electrolyte can alter the way of zinc nucleation,thereby enabling stable zinc stripping/deposition behaviour.In detail,the instantaneous nucleation in bare electrolyte shifts to progressive nucleation after involving optimal concentration of Ce₂（SO₄）₃ or La₂（SO₄）₃ as a result of the preferential adsorption of Ce3+or La3+.Meanwhile,these cations can suppress 2D diffusion to assist uniform zinc deposition.Zn//Zn battery with this electrolyte is able to cycle for more than 400h at 1m A cm-2-1m Ah cm-2 while it only runs for about 38h in the bare electrolyte.The capacity retention of Zn//Na V₃O₈·1.5H₂O battery has been significantly enhanced to 87.0%from 68.1%at 5A g-1 as well.（2）An electrolyte with sulfolane involved in Zn SO₄ to reshape the interfacial double layer has been designed.In specific,this electrolyte can predominately occupy the inner Helmholtz layer and interact with Zn2+to regulate the interfacial behaviour of Zn2+.In addition,the corrosion byproducts can be eliminated as well,critically improving the batteries performance.With an optimal amount of sulfolane,Zn//Zn battery can operate more than 1000h under 1m A cm-2-1m Ah cm-2,and the capacity of Zn//Na V₃O₈·1.5H₂O battery is higher than that of battery without sulfolane（168.10m Ah g-1 vs 130.90m Ah g-1）.