Study On The Performance Of Lithium/Sodium Ion Battery Anodes And Lithium Metal Anodes Based On Transition Metal Oxygenates And Chalcogenides

With the continuous development of human society and technology,traditional fossil energy can no longer meet people’s needs,especially after the emergence of electric vehicles,this problem is particularly obvious,the development of stable and reliable energy storage system is imminent.Lithium-ion battery has been a research hotspot in the field of energy storage system in recent years due to its advantages in high energy density and high stability.The electrode material of battery is the main factor to determine the performance of battery.At present,the graphite anode material with the highest commercial degree has a low specific capacity,which is difficult to meet the needs of people.Transition metal oxide compounds are excellent potential anode materials for lithium/sodium batteries due to their advantages of high theoretical capacity,abundant storage and environmental friendliness.However,they also have some problems such as low cycle efficiency and short life span.The transmetallic selenides have excellent mechanical and thermal stability,narrow or zero band gap characteristics and high theoretical specific capacity,but they are still limited by low electrical conductivity and poor cyclic stability.Lithium metal anode has a high theoretical specific capacity（3860 m Ah g-1）and the lowest standard potential（-3.04 V vs.SHE）,but it also has the shortcomings of the growth of lithium dendrites,electrode interface instability and so on.In view of the above problems,this paper puts forward some solutions.The flower-like cobalt selenide（CoSe@NC）was prepared by in situ selenization and carbon coating.The specific capacity of lithium and sodium battery anode at 1 A g-1 current density can reach 575 m Ah g-1 and 358 m Ah g-1,200 cycles capacity retention rates can reach78.41%and 79.43%,respectively.The carbon coating improves the electrical conductivity of the material,and the flower-like structure improves the adverse effect caused by the volume change.The two work together to improve the magnification properties of CoSe@NC materials.The performance of Ni-CoSe@NC materials prepared by in situ synthesis has been further improved due to the removal of the conductive agent,and also has good performance as the lithium metal anode collector.Cu-TNT lithium metal anode collector was prepared by growing TiO₂ nanotubes on copper mesh by external coating and internal etching.The collector has a large three-dimensional space due to the copper mesh skeleton,the titanium dioxide nanotubes provide a large surface area,and the titanium dioxide is rich in oxygen defects.Due to the presence of copper mesh skeleton,the collector has a large three-dimensional space,TiO₂ nanotubes provide a large surface area,and the TiO₂ is rich in oxygen defects.As collector of lithium metal anode,Cu-TNT can effectively reduce the nucleation overpotential of lithium（-0.042 V at 1 m A cm-2 current density）,regulate the uniform deposition of lithium,increase the mechanical strength of SEI layer,inhibit the growth of lithium dendrites,and improve the interface stability of the electrode surface.At 1 m A cm^-2,1 m Ah cm^-2,uesing ester-based electrolyte and ether-based electrode,Cu-TNT-Li||Cu-TNT-Li symmetrical battery have stable cycled 500 h and 800 h respectively.Match Li Fe PO4 as the cathode material,LFP||Cu-TNT-Li cell showed excellent capacity retention rate and multiplier performance in both ester-based electrolyte and ether-based electrode.