Preparation Of Sulfur Cathode Material Of Carbon Aerogel Modified With Cage-type Calixarene Compound And Electrochemical Performance For Lithium Sulfur Batteries

Lithium-sulfur?Li-S?battery is considered as candidate for next-generation energy sources for the extremely high theoretical specific capacity(1675 m Ah g^-1)of the sulfur cathode.Furthermore,the obvious advantages of element sulfur including non-toxic,abundance,inexpensive and environmental friendly,make it attractive for the potential applications.However,the further researches of Li-S batteries have been hampered by several critical issues,such as the low conductivity of sulfur and the low utilization of active materials.What's more,the polysulfides?Li₂S_n with n=4,6,8?dissolve in organic electrolytes and produce shuttle effect.The cage-type compound presents cage structure,and as a surface modifier it may provide some selective capturing ability for polysulfides.Considering the fact that p-sulfonatocalix[4]arene?SC4A?with the diameter can adequately accommodate polysulfides,we choose SC4A to modify carbon materials.The specific cage-type calixarene is implanted in carbon materials may provide an opportunity to suppress shuttle effect and improve electrochemical performance.In addition,the ACA provides promising host material with large specific surface area and affluent interconnected mesoporous channels.Therefore,we propose to implant cage-type p-sulfonatocalix[4]arene in ACA for capturing polysulfides.Benefiting from the cage-type calixarene capturing polysulfides,the cathode delivers an outstanding electrochemical performance with initial capacity of1304.7 m Ah g^-1 at 0.2 C.Furthermore,it displays excellent long-term cyclic stability with maintaining 884.7 m Ah g^-1 after 300 cycles at 0.5 C.Density functional theory?DFT?adsorption calculations support the strong interaction between the calixarenes and polysulfides and reveal the capture mechanism.This paper also prepared calix[4]arene sulfonamide derivative?C4SAD?which provide a switch function for anchoring polysulfides.We successfully prepared CDCA composite via C4SAD bonding on ACA.Li-S batteries with CDCA/S as the cathode display excellent specific capacity and cycle stability.The initial discharge capacity shows 1240.1 m Ah g^-1 at 0.2 C.Furthermore,it displays excellent long-term cyclic stability with maintaining 896.2 m Ah g^-1 after 300cycles at 0.5 C.