Preparation Of Mn-based Prussian Blue Analogues And Their Research In Li~+/K~+ Batteries

Prussian blue,as a kind of material with a long history,has been widely concerned in recent years due to its special metal-organic framework structure.Due to its high adjustability,its iron ions can be converted into other transition metal ions to form various Prussian blue analogues.Among them,manganese Prussian blue analogues have been widely used in many fields because of the particularity of manganese.In the field of electrochemical energy storage,manganese Prussian blue has been found to show excellent electrochemical performance in the anode of the lithium-ion battery,sodium-ion battery and potassium ion battery,which has high research value.At the same time,the working voltage of manganese Prussian blue analogues in potassium ion batteries is as high as 4.2 V,which puts forward higher requirements for the corresponding electrolyte of potassium ion batteries.It is also of great significance to study the compatibility of potassium ion organic electrolyte and manganese Prussian blue analogues.In this paper,we mainly studied the controlled preparation of manganese Prussian blue analogues,controlled the morphology and structure of Prussian blue analogues by different synthesis methods,applied them to the anode of lithium-ion battery and the anode of potassium ion battery respectively studied the relationship between the lithium storage and potassium supply capacity of Prussian blue analogues and their structure and morphology;at the same time,we studied the manganese Prussian blue analogues The potassium ion organic electrolyte as cathode was studied.The specific research contents are as follows(1)By introducing a small amount of methanol into the reaction system,the cubic manganese Prussian blue analogues were prepared by the classical hydrothermal synthesis method.They were applied to the anode of lithium-ion batteries to study the relationship between the lithium storage capacity and morphology and structure.At the same time,when methanol was replaced by other soluble organic solvents,it was found that the addition of alcohol organic solvents could effectively reduce the microparticle size of manganese Prussian blue analogues.Finally,the electrochemical lithium storage mechanism of Prussian blue analogues as anode materials for lithium-ion batteries was analyzed by in-situ XRD,HRTEM and electrochemical kinetics tests.(2)By adjusting the chelating agent and reaction temperature,a self-assembly method for the preparation of monoclinic manganese Prussian blue analogues was explored.It was applied to the positive electrode of potassium ion battery to study the relationship between its potassium supply ability and binding and morphology.At the same time,the morphology,chelation and nucleation of this kind of manganese Prussian blue analogues were analyzed,and the self-assembly phenomenon of Prussian blue analogues was discussed.(3)Using manganese Prussian blue as cathode,the compatibility of potassium ion organic electrolyte with manganese Prussian blue analogues was studied.By adjusting the type of solute,cyclic and chain carbonates,ether solvents,fluorinated additives and nitrile additives,the electrolyte was evaluated from the perspectives of capacity,overpotential,coulomb efficiency and working voltage.There are 37 figures,3 tables and 110 references in this dissertation.