Design And Preparation Of The Interlayer That Inhibits The Shuttling Effect Of Lithium Sulfur Battery And The Cathode Structure

Because of high energy density,low cost and environmental friendliness,lithium sulfur battery has been widely concerned by researchers.But at the same time,the shuttling effect of polysulfide in lithium sulfur battery has hindered the development and practical application of lithium sulfur battery seriously.Although the introduction of solid electrolyte is considered as the ultimate solution to solve the shuttling effect of lithium sulfur battery,solid-state lithium sulfur battery also faces many problems.In this paper,several different methods to inhibit the shuttling effect of polysulfide were studied,including the design of sandwich-type structure interlayer,the synergetic use of titanium carbonitride cathode additive and graphene interlayer.At last,the design of composite cathode structure of solid-state lithium sulfur battery has been studied in this paper.Firstly,a multi-component sandwich-type interlayer was designed and prepared in this paper to inhibit the shuttling effect and self-discharge of lithium sulfur battery.The sandwich-type interlayer was composed of a carbon nanofibers base,an intermediate adsorption layer constituted by vanadium disulfide and carbon nanotubes,and a graphene coating layer.Among them,carbon nanofibers substrate,carbon nanotubes and graphene form a three-dimensional conductive network.Vanadium disulfide had strong chemical adsorption to polysulfide,which could inhibit the shuttling effect of polysulfide effectively.After 1150 cycles of the lithium sulfur battery with this sandwich-type interlayer,the specific capacity was still maintained at 605 m A h g^-1 at the current density of 1C,and the average attenuation rate per cycle was only 0.041%.Moreover,the suitable high voltage of vanadium disulfide could inhibit the self-discharge of lithium sulfur battery significantly.Subsequently,a more convenient and feasible method was adopted in this paper to inhibit the shuttling effect of polysulfide in lithium sulfur battery.Titanium carbonitride was used as cathode additive to anchore sulfur at the source of formation of polysulfide,and a graphene interlayer was coated on the side of the separator near the cathode as a physical interlayer.Synergy effect between this two materials were used to inhibit the shuttling effect of polysulfide.As a result,the average attenuation rate per cycle was only 0.049%.Finally,the design of composite cathode structure of solid-state lithium sulfur battery was investigated.The flocculent three-dimensional porous structure of cotton was used as the framework of this composite structure.The cotton was immerse into the precursor solution of lithium lanthanum zirconium oxygen and graphene oxide aqueous solution.Then one-step sintering method was adopted to fabricate the composite structure of reduced graphene oxide coated lithium lanthanide zirconium oxygen nanoparticles supported by cotton carbon skeleton.At last,the active material sulfur was infiltrated into the porous structure of cotton carbon skeleton by hot melt method,then the composite cathode was obtained,and it showed low impedance and high initial discharge capacity of 1028m A h g^-1 when this composite cathode was applied in the solid-state lithium sulfur battery.In conclusion,this paper proposed several methods to inhibit the shuttling effect of lithium sulfur battery effectively,and made a reasonable design for the cathode structure of solid-state lithium sulfur battery.The research in this paper has played an active role in promoting the development and practical application of lithium sulfur battery.