Interface Modulation And Properties Of High-performance Zinc Metal Anode

Battery systems play a crucial role in the storage and conversion of clean energy.Lithium-ion batteries are the energy storage system with the highest energy density and longest cycle life.However,lithium-ion batteries are faced with a shortage of lithium resources and safety problems caused by flammable and toxic organic electrolytes.Rechargeable zinc ion batteries（ZIBs）have the benefits of being environmentally friendly,abundant reserves,high safety and low cost,which are ideal for large-scale energy storage.However,ZIBs still face several crucial challenges.The uncontrolled zinc dendrite growth,hydrogen evolution,and corrosion,which hamper the practical application of ZIBs.The zinc anode from the battery was modified in this research to address the issues of zinc dendrite growth,hydrogen generation,and corrosion.Constructing organic and inorganic zinc anode protective layers and electrolyte additives effectively improved the electrochemical performance of zinc ion batteries.The main research content is as follows:（1）We investigated a polymer coating layer for a dendrite-free zinc anode,which is prepared by dropping a polycaprolactone solution containing zinc trifluoromethanesulfonate（Zn（CF₃SO₃）₂）onto zinc foil（Zn@PCLZ）,which was combined with an ammonium metavanadate（NVO）cathode to assemble a full cell.The PCLZ protective layer has a unique hydrogen bond network,which can promote the migration and uniform nucleation of Zn2+,effectively alleviating zinc dendrites and side reactions.A symmetrical cell with the Zn anode modified by a polymer coating layer exhibits a long cycle lifespan,which can cycle 2000 h at a current density of 0.5 m A cm^-2.In addition,the Zn@PCLZ||NVO full battery has a specific capacity of 99.19 m Ah g-1 after 2000 cycles at a high current density of 5 A g-1,exhibited good cycle stability.（2）The inorganic protective layers of zinc anode were prepared by eletrodeposition.Using pure zinc foil as the working electrode,two kinds of rare earth oxides,erbium oxide（Er₂O₃）and dysprosium oxide（Dy₂O₃）,were introduced into the ZnSO₄ electrolyte used for electrodeposition,and the deposition parameters were adjusted.Zn@Er₂O₃ and Zn@Dy₂O₃anodes were prepared by composite electrodeposition.It was found that the two substances could promote zinc deposition.In addition,compared with the rare earth oxide composite electrodeposition electrolyte which is insoluble in water,the deposition of Zn@Ce O2 anode material is more uniform by using Ce（NO3）3 salt solution as the deposition electrolyte.The assembled symmetrical battery can be stably cycled for 260 h at a current density of 0.5 m A cm^-2.（3）The effects of saccharin concentration on zinc deposition/stripping and electrochemical performance of zinc ion batteries were studied.Saccharin-derived anions preferentially adsorbed on the surface of Zn metal to regulate zinc deposition behavior and inhibit the generation of by-products and the growth of zinc dendrites.The Zn||Zn symmetric battery assembled with saccharin as electrolyte additive shows a great cycling performance more than 1000 h at 0.5 m A cm^-2.（4）Ammonium dihydrogen phosphate（NH₄H₂PO₄）was added to the traditional Zn（CF3SO3）2 electrolyte as an additive.NH₄⁺ had great adsorption on the surface of Zn,forming a “shielding effect” and blocking the direct contact between water and Zn.In addition,NH₄⁺and H₂PO₄^-can synergistically maintain the p H stability of the electrode-electrolyte interface.The Zn||Zn symmetric battery assembled with NH₄H₂PO₄ as electrolyte additive had excellent electrochemical performance after cycling for more than 1400 h at 0.5 m A cm^-2.