Lithium-sulfur batteries have attracted attention because of their high energy density.However,the "shuttle effect" caused by the dissolving of polysulfide in the electrolyte has greatly hindered the widespr...Lithium-sulfur batteries have attracted attention because of their high energy density.However,the "shuttle effect" caused by the dissolving of polysulfide in the electrolyte has greatly hindered the widespread commercial use of lithiumsulfur batteries.In this paper,a novel two-dimensional TiS2/graphene heterostructure is theoretically designed as the anchoring material for lithium-sulfur batteries to suppress the shuttle effect.This heterostructure formed by the stacking of graphene and TiS2 monolayer is the van der Waals type,which retains the intrinsic metallic electronic structure of graphene and TiS2 monolayer.Graphene improves the electronic conductivity of the sulfur cathode,and the transferred electrons from graphene enhance the polarity of the TiS2 monolayer.Simulations of the polysulfide adsorption show that the TiS2/graphene hetero structure can maintain good metallic properties and the appropriate adsorption energies of 0.98-3.72 eV,which can effectively anchor polysulfides.Charge transfer analysis suggests that further enhancement of polarity is beneficial to reduce the high proportion of van der Waals(vdW) force in the adsorption energy,thereby further enhancing the anchoring ability.Low Li2 S decomposition barrier and Li-ion migration barrier imply that the heterostructure has the ability to catalyze fast electrochemical kinetic processes.Therefore,TiS2/graphene heterostructure could be an important candidate for ideal anchoring materials of lithium-sulfur batteries.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62104168,11604235,andU1510132)the Beijing Institute of Technology Research Fund Program for Young Scholars+2 种基金the Natural Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi,China(Grant No.2019L0309)the Natural Science Foundation of Shanxi Province,China(Grant Nos.201901D111125 and 20210302123201)the Shanxi Scholarship Council of China。
文摘Lithium-sulfur batteries have attracted attention because of their high energy density.However,the "shuttle effect" caused by the dissolving of polysulfide in the electrolyte has greatly hindered the widespread commercial use of lithiumsulfur batteries.In this paper,a novel two-dimensional TiS2/graphene heterostructure is theoretically designed as the anchoring material for lithium-sulfur batteries to suppress the shuttle effect.This heterostructure formed by the stacking of graphene and TiS2 monolayer is the van der Waals type,which retains the intrinsic metallic electronic structure of graphene and TiS2 monolayer.Graphene improves the electronic conductivity of the sulfur cathode,and the transferred electrons from graphene enhance the polarity of the TiS2 monolayer.Simulations of the polysulfide adsorption show that the TiS2/graphene hetero structure can maintain good metallic properties and the appropriate adsorption energies of 0.98-3.72 eV,which can effectively anchor polysulfides.Charge transfer analysis suggests that further enhancement of polarity is beneficial to reduce the high proportion of van der Waals(vdW) force in the adsorption energy,thereby further enhancing the anchoring ability.Low Li2 S decomposition barrier and Li-ion migration barrier imply that the heterostructure has the ability to catalyze fast electrochemical kinetic processes.Therefore,TiS2/graphene heterostructure could be an important candidate for ideal anchoring materials of lithium-sulfur batteries.
