Research On The Novel Cathode Materials Of Lithium Sulfur Battery

Sulfur has the advantades of low cost,abundance in source and a high theoretical specific capacity which was widely studied as cathode of lithium sulfur battery.But the insulator of sulfur and lithium sulfide,the shuttle effect caused by polysulfides during charge-discharge process hinder the evolution of lithium-sulfur battery.In this thesis,conductive polyaniline was combined with sulfur to improve the conductivity and adsorb polysulfide confining the shuttle effect.Polyaniline-sulfur-carbon composite doped with sulfuric acid,acetic acid and nitric acid was prepared in water-ethanol system to study the performance of lithium-sulfur battery affected by dopant acid of polyaniline.Through the electrochemical test,it was found that composite doped with different acid exhibited different cycling performance.Polyaniline doped with different protonic acid has different adsorption with polsulfide via quantum chemistry calculation.Utilizing a dopant of protonic acid,acidic phosphate ester,which owns abundant binding sites and large binding energy,polyaniline-sulfur-carbon composite was synthesized,delivering an initial specific capacity of 1283 mAh/g and a retention of 86.4% after 100 cycles at 0.5 C.