Energy Storage Performance Of Manganese-based Materials In Environmentally Friendly Aqueous Zinc-ion Batteries

Rechargeable aqueous zinc ion batteries(ZIBs)not only show the advantages of low cost and high safety,but also have the characteristics of environmental protection and pollution-free,because they use nonflammable water solution as electrolyte.It is an environment-friendly energy storage equipment with great development potential.Among many materials,manganese-based materials are considered as the most promising cathode materials for aqueous zinc ion battery due to their low toxicity and abundant resources.In this paper,the ZnMn-BDC MOF precursor was firstly synthesized,and then the manganese based compounds were prepared by heat treatment under different atmospheres to explore the influence of different heat treatment atmospheres on their electrochemical properties.Then,MnO₂ nanowires prepared by different hydrothermal methods are used as the cathode materials of ZIBs to explore the influence of MnO₂ nanowires prepared by different methods on their electrochemical properties.The experimental results are as follows:ZnMn-BDC heat treated material in air ZnMn-BDC-500(ZnMn₂O₄)has better electrochemical performance,which is more suitable as cathode materials for ZIBs.At the current density of 200 m A/g,the reversible specific capacity is up to 373.8 m Ah/g after cycle activation.At the same time,the material has excellent multiplier performance,when the current density is 1 A/g,it can still maintain 53 and 52 m Ah/g of average charging and discharging specific capacity,and Coulomb Efficiency is as high as 98.1%,which indicates that the ZnMn-BDC heat treated material has better zinc storage capacity.The experimental results show that MnO₂-2(?-MnO₂)nanowires prepared by hydrothermal method have more excellent energy storage properties.At the current density of 200 m A/g,after 100 charges and discharges,the specific discharge capacity and specific charge capacity are 213.5 m Ah/g and 216.5 m Ah/g,and the Coulomb Efficiency is about 98.6%.After 100 charge and discharge cycles at the high current density of 1A/g,the discharge and charge specific capacity of MnO₂-2 are 64.1 and 64.1m Ah/g,the Coulomb Efficiency is about 100%,and the capacity retention rate is about83%,which demonstrate a good cycle and multiplier performance.