Synthesis And Modification Of Two-dimensional MnO_x As Cathode Material For Aqueous Zinc Ion Battery

Aqueous zinc-ion batteries(AZIB)are one of the promising options for large-scale grid energy storage in the future.Compared to lithium-ion batteries or lead-acid batteries,AZIB uses a neutral,inexpensive aqueous electrolyte instead of easy Combustion,expensive organic electrolyte or strong acid,alkaline aqueous electrolyte,makes it have some unique advantages in terms of price,safety,and environmental protection.Secondly,compared to other alkaline metal batteries,the electrolyte and electrode materials used by AZIB are rich in storage and inexpensive,can be stable in the air,and do not cause redox reactions with water and oxygen,and in terms of battery assembly It is more convenient and quick,and can also greatly reduce the manufacturing cost of the battery.At present,the research on water-based zinc ion batteries is still mainly in the cathode material,of which MnOx has the advantages of low cost and high safety.Among them,a-mno,b-mno2,r-mno2 has also been a research hotspot,However,in general,the capacity transfer and cycle stability of manganese oxide materials are limited by the incomplete zincation and structural pulverization induced by the bulk,so that its overall performance cannot meet expectations.Here,we first prepared two-dimensional(2D)MnOx nanosheets by liquid phase synthesis,and explored their electrochemical performance.They have a capacity of 278 mAh g-1 at a 1C rate performance and a 5C rate.After 2800 cycles,the capacity retention rate is relatively poor.Compared with the conventional a-mno,b-mno2,r-mno2,it does not meet our expectations for the two-dimensional structure in the zinc ion battery system.In order to improve the conductivity of the two-dimensional(2D)MnOx nanosheet material,we constructed a liquid-phase epitaxial polymerization strategy to fabricate twodimensional(2D)MnOx / polypyrrole nanosheets to improve the structural stability through the effective use of active substances and through the polymerization framework To enhance zinc ion storage.With a super high capacity of 408 mAh g-1 at 1C rate performance,AZIB achieved an excellent capacity retention rate of 78% after 2800 cycles at 5C rate.Electrochemical and morphological characterization indicate that the unique 2D structure contributes to electronic / ionic conductivity and structural stability.The epitaxial polymerization of conductive polymers in the liquid phase provides a new perspective for the synthesis of high-performance electrode materials and two-dimensional conductive polymers.