Study On The Properties Of Lithium/Sulfur Secondary Batteries

The lithium-sulfur battery has many attractive properties, it has a high theoreticalenergy density, sulfur also has the advantage of abundance in nature and low cost. Solithium sulfur battery is the most promising candidate in the future secondary batteries.But the low discharge capability and cycle life limit its further application anddevelopment. In this paper, we researched the sulfur composite materials of thesecondary lithium sulfur battery, also include its electrolyte and binder.In this study, a series of sulfur composite materials were synthesized throughheating the mixture of element sulfur and carbon materials. Through the specificsurface area, volume surface morphology of carrier carbon materials and theelectrochemical performance of the battery, we indicated that the best matrix materialis Bp2000super conductive carbon. Its initial discharge specific capacity is1385.1mAh/g. The specific capacity still keeps as high as1080.2mAh/g, after30cycles at room temperature just22%fade.Add appropriate amount of γ-aluminium oxide in the sulfur carbon compositeswill help promote redox reaction, reduce the loss of sulfide together. Sulfide loss isnot only make the reduce of positive active materials, but also reaction with thenegative metal lithium, rise the viscosity of electrolytic liquid, affect the cycleproperties of the battery. The results indicated that the best addition amount was1.5wt%.In this paper, a novel sulfur composite material was synthesized throughelectrolyzing sodium sulfide solution. In this way, improved the sulfur activematerials electrode electrochemical utilization and the cycle performance of thebattery, also this method is simple and easy to preparation.In this paper, we comprised the LiPF₆-EC/DMC, and LiTFSI-DOL/DMEelectrolyte, PTFE and gelatin binder and simple analysis of its influence on theperformance of the battery. The results show that the performance of LiPF₆-EC/DMCelectrolyte is stable, and LiTFSI-DOL/DME electrolyte can better dissolve the sulfide,so it can effectively improved the previous cycle capability, but when sulfidedissolved in the electrolyte to a certain degree the capability would decreased. Gelatinbinder improve the bonding and dispersion of the electrode, also could reduce the resistance, improve the cycle performance of the battery.