Preparation Of Carbon Sulfur Electrode Modified By Organic Compound With Transition Metal And Electrochemical Performance For Lithium Sulfur Batteries

As next-generation energy storage device,Li-S battery is gaining particular attention owing to environment-friendly,low cost and abundant reserves of sulfur.Meanwhile,Li-S battery presents excellent theoretical specific capacity and specific energy density,which higher than conventional lithium-ion battery.Thus,for solving the shuttle effect of the battery during electrochemical cycle,many works have been devoted to reducing the loss of sulfur and improving the cycle stability of the battery.This work reports that the porous nanostrucrure and nitrogen,silver-doping carbon aerogels were successfully prepared by in situ and sol-gel strategy.According to the modification of tetra-nuclear silver metal organic knots and polyethylene glycol for carbon aerogel,the special modifiers provide more nanochannels for carbon aerogel to significantly restrict the loss of sulfur,suppress shuttle effect and display remarkable electrochemical performance.The prominent performance mainly benefits from the synergistic effect of interconnected nanochannel network structure,the transition metal sulfide（Ag₂S）and nitrogen doping.Especially,the PEG-Ag-CA material delivers discharge capacity of 1313.6 m Ah g^-1 at a rate of 0.2 C in first cycle,and retains1143.8 m Ah g^-1 after 100 cycles.Meanwhile,we design a new approach.The as-prepared metal organic frameworks ZIF-8 as a self-template,used to adjust the size of carbon aerogel and modify its structure.The metal oxide can significantly suppress shuttle effect,and show good electrochemical performance.Notably,the as-prepared material exhibits smaller carbon spherical size,6ZIF-8@CA/S material provides an more excellent sulfur storage space for sulfur,and sulfur was evenly distributed in carbon material to positively participate in the reaction during cycling.Moreover,the strong bonding interaction between zinc oxide（Zn O）and lithium polysulfide can promote the active sulfur utilization and further enhance the reversible capacity and cycling.In addition,the theoretical calculations by density functional theory（DFT）further confirm the excellent absorption effect between prepared material and lithium polysulfide,and fully prove the reason that prepared materials present excellent electrochemical performance.