Synthesis And Characteristic Of Sulfur-graphene Composite As The Cathode Material Of Lithium-sulfur Battery

Lithium secondary battery is one prominent future portable energy storage device,employing sulfur particle as the main cathode energy storage material is performingsound results. One major carbon-sulfur composite initiated by our lab is analysed. Anewly structured All-Solid-State lithium sulfur battery is introduced and studied.This article will carry out the composition of sulfur and two kinds of graphene indifferent forms, resulting a sequence of composite with good performance.Thesecomposites guarantee a high load of sulfur and relatively good electrochemicalperformance and also surmount several long harmed disadvantages of lithium sulfurbattery such as low conductivity, low cyclic performance etc. What’s more, it in certaindegree greatly avoid the harmful “Shuttle Effect”, and thus the relatively low sulfur loadof graphene is ameliorated.We use thermal exfoliated graphene (TGN) as the substrate to embed sulfur particles.TGN is a kind of very thin film with which the structure could perform as an excellentmembrane outside the sulfur particles, in this way it would not only greatly developed abetter conductivity but also barricade the tunnel by which most of the active materialescape from the cathode. Followed by, we performed further amelioration of this TGN-Scomposite: wrapping it with the reduced graphene oxide(rGO), a kind of material withboth high conductivity and good physical properties, forming the ultimate composite ofthis article-the rGO-TGN-S composite. According to electrochemical statics, thisultimate composite performs a far more better result than that of TGN-S. We at the sametime studied other factors that we think would affect the performance of this composite,including different sulfur load, different TGN synthesizing temperature as well asdifferent exfoliating atmosphere, different rGO covering ratio, different Al foil thicknessect. We could learn from the result that there exist a best rGO covering ratio and bestsulfur load along with the best Al foil thickness which will in greatest degree benefit theperformance. The properties of TGN producing at1050℃in the atmosphere of N2or Arusing a multiple step exfoliating method shows the best. The sickness of15μm coating ofactive material on the aluminum foil shows the best electrochemical performance.A newly structured All-Solid-State Li-S battery is brought about by us as an exploreand comparison. LATP ceramic solid electrolyte and CPE semi-solid electrolyte areutilized respectively as main electrolyte and separation membrane, CPE separation issupposed to reduce the contacting resistance between LATP and cathode.In order to test the property of this solid battery and the performance of rGO-TGN-Sin solid battery,we structured one control group: the composite produced by ball millingbp2000and sulfur, followed by some control factors such as the comparison ofelectrochemical performance between presence and absent of CPE. Consequently, rGO-TGN-S shows a better cyclic stability and the exist of CPE greatly improved totalbattery performance.